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Sports Supplements – Creatine For Endurance Athletes

Admin — Sat, 02 Oct 2010 10:44:28 +0000

Creatine supplements can boost your endurance training without encouraging weight gain

The correct dose of creatine will improve endurance athletes performance without making them gain weight!

Creatine (methylguanidine-acetic acid) was discovered in 1832, but athletes have been taking it – in hopes of improving their performances - for only the last 10 years. Over that time period, a scientific consensus has emerged that creatine supplementation can indeed increase muscular strength and power and improve performances in relatively short-duration, high-intensity activities. The potential benefits of creatine supplementation for longer-duration, lower-intensity exertion (i. e., for endurance-type athletes) have, however, been hotly debated.

[MAM]

To get a better insight into this debate, you should understand that muscle cells use creatine to form creatine phosphate, a high-energy compound which can be used to rapidly synthesize ATP, the ‘energy currency’ utilized by all cells in the human body. Whenever a nerve cell fires, a muscle fibre contracts, or a kidney cell actively filters some urine, ATP ‘pays the bills’ (i. e., furnishes the energy needed to carry out the activity).

Creatine phosphate is also a ‘buffer’ which tempers the increase in intramuscular acidity associated with intense exercise; in this role, creatine might help allay the fatigue which can be caused by a drop in muscular pH. Because of these two key actions of creatine (ATP creator and buffer), athletes have become extremely interested in supplementing their diets with this unique compound.

There is no question that creatine supplementation increases the amount of creatine phosphate within muscle cells, sometimes by up to 50 per cent. Research support for creatine has been strong, and PP readers will be aware of a lot of it. Studies going as far back as 1986 have shown that when creatine phosphate concentrations drop within muscle cells, those fibres are unable to exhibit normal force production. In addition, a variety of different scientific investigations have linked creatine supplementation with greater muscular force production and power, as well as higher sprinting speeds, faster cycling velocities, and quicker swimming movements during very high-intensity efforts. As a result, there are few elite power athletes in the world who have not given creatine supplementation a try.

But what about endurance athletes?
In contrast, there’s no question that creatine is less popular with the endurance crowd, compared to the power people (one of creatine’s side effects – weight gain – has helped to minimize its popularity among endurance competitors). Somewhat surprisingly, little creatine research has been carried out with endurance athletes, and the few investigations which have been completed have yielded inconsistent results.

Thus, more work has been needed, and in a relatively new study, researchers at Kingston University in Surrey and the University of Tasmania in Australia looked at the effects of creatine on 16 endurance kayakers who possessed a high level of fitness (VO2max = 67.1 ml/kg.min). All 16 subjects took part in an initial workout which consisted of three work intervals which were completed on a kayak ergometer and which lasted for a duration of 90, 150, and 300 seconds. The athletes completed each interval at the highest-possible intensity and recovered completely (heart rate back to resting level) between intervals (‘The Effects of Creatine Supplementation on High-Intensity Exercise Performance in Elite Performers,’ European Journal of Applied Physiology, vol. 78, pp. 236-240, 1998).

The subjects were then randomly assigned to either a ‘creatine group’ or a placebo group. Creatine-group members took four five-gram doses of creatine monohydrate per day for a total of five days, while placebo-group athletes ingested four five-gram supplements of glucose daily. After five days, both the creatine and glucose athletes repeated the three-interval, max-intensity workout.

There followed a four-week ‘washout period’, during which the subjects took neither the creatine nor the glucose supplements. Research has shown that four weeks is long enough to bring an elevated muscle creatine-phosphate concentration back to ‘normal’. Following the four-week washout, all subjects participated in the three-interval workout yet again. Following this re-test, the previous placebo subjects ingested creatine for five days (4 x 5 grams per day) while the former creatine athletes took the glucose placebo (this is what’s called a ‘crossover’ design). After five days, the athletes tried the three-interval session one last time.

Fatter – but stronger
In just five-days time, the creatine supplements made the athletes gain weight. Creatine supplementers gained on average two kilograms (4.4 pounds), or almost one pound per day during creatine supplementation. Meanwhile, the placebo-subjects’ weights held steady.

Creatine also increased the quality of the athletes’ efforts during the three-interval workouts. During the 90-second interval, the kayakers completed about 16 per cent more work when they had supplemented with creatine, compared to taking the placebo or being in the control condition (at the beginning of the study and after the washout period). During the 150-second interval, the athletes completed 14 per cent more work with creatine, and for the five-minute (300-second) interval the creatine subjects hit 7 per cent more work. Blood-lactate levels were also higher for creatine athletes after the 150- and 300-second intervals, compared to control and placebo subjects. However, this was not a bad thing; it merely reflects the fact that the creatine-supplemented athletes were able to work at a higher intensity (and thus ‘cough up’ a bit more lactate).

[MAM]

Note that the advantage associated with creatine supplementation became smaller as the duration of the work interval increased. This is not terribly surprising. As work-interval duration increases, the relative amount of the energy which is needed to complete the interval which is actually coming from creatine phosphate decreases, as the creation of ATP from the breakdown of carbohydrate (rather than from the transfer of a phosphate group from creatine phosphate) becomes much more important. As work-interval duration increases, exercise intensity also declines, which means that creatine phosphate’s role as a buffer becomes less important.

That doesn’t mean that the value of creatine supplements becomes negligible for the endurance athlete carrying out relatively long work intervals, however, because creatine supplementation did produce significant improvements in work output during the longest (five-minute) intervals utilized in this study. Thus, it is tempting to say that creatine supplementation would be very beneficial to endurance athletes during their training (150-second to five-minute intervals are commonly employed by endurance competitors).

Will it also be true for runners?
However, remember that the gains in this study associated with creatine supplementation were obtained by endurance kayakers, not runners. Endurance kayakers, of course, are seated during exercise, and therefore the gains in weight associated with taking creatine are not so troubling to them (the kayak and water – not the athletes’ working muscles – support most of the extra weight, and the only real drawback linked with weight gain is a slight uptick in drag, i. e., friction between the kayak and the water). The same is true for cyclists, but even one-pound gains can hurt the efficiency of runners; four-pound upswings will almost certainly slow them down.

What causes the gain in weight? Research indicates that most of the short-term weight gain associated with creatine supplementation is probably due to water retention. Eric Hultman and his outstanding team of researchers were able to show recently that as creatine storage by muscles increases, urinary volume tends to decline (‘Muscle Creatine Loading in Men,’ Journal of Applied Physiology, vol. 81, pp. 232-237, 1996). Over the long term, much of the weight gain associated with creatine could be produced by an actual increase in muscular mass, as the higher-quality workouts linked to creatine supplementation could lead to advances in muscle size, at least among athletes who are strength training with rather heavy resistances.

The answer is yes – but
Should endurance runners take creatine supplements? There is little doubt that creatine supplementation can improve the quality of endurance-runners’ workouts. Several years ago, scientists from England and Estonia asked five endurance runners at Tartu University in Estonia to supplement their diets with 30 grams (six five-gram doses per day) of creatine monohydrate per day for six consecutive days. During this six-day period, five other Estonian runners of comparable ability consumed a glucose placebo instead of creatine. All runners were unaware of the true compositions of their supplements (‘Creatine Propels British Athletes to Olympic Gold Medals: Is Creatine the One True Ergogenic Aid?’ Running Research News, vol. 9(1), pp. 1-5, 1993).

Prior to and following the six days of supplementation, the athletes ran four 300-metre and (on a separate day) four 1000-metre intervals, with three minutes of rest between the 300-metre work intervals and four minutes of recovery after the 1000-metre reps. Creatine dramatically improved the runners’ efforts. Compared to the placebo group, improvement in the final 300-metre interval (from pre- to post-supplementation) was more than twice as great for creatine users, and improvement was more than three times as great for creatine supplementers in the final 1000-metre interval. Total time required to run all four 1000-metre intervals improved from 770 to 757 seconds after creatine supplementation, a statistically significant change. Meanwhile, placebo-group members’ performances remained the same (about 775 seconds for the four intervals). Creatine supplementation improved the average quality of the 1000-metre intervals by a little over three seconds.

Of course, improvements in workout quality generally lead to improvements in competitive performances. Amazingly enough, workout-quality upgrades can occur after just five to six days of creatine supplementation. This all makes creatine sound wonderful, but there’s still that nagging problem of weight gain.

Will you always gain weight?
However, bear in mind that the water-retention-related gain in weight is primarily a function of the high creatine-loading doses (20 to 30 grams per day) used both in many research studies and by many athletes. In a very recent study, a lower loading dose (6g of creatine per day) produced only a one-pound gain in weight (‘Why Your Creatine Consumption Is Costing You Too Much,’ Running Research News, vol. 14(7), pp. 1-4, 1998).

And in fact researchers are finding that lower loading doses can be as effective as the big, 20-gram per day intakes at building up muscle creatine-phosphate concentrations, provided that the lower doses are taken over a little bit more time. Basically, the new research is revealing that six one-half gram doses of creatine per day (for a total of three grams daily) over the course of about 30 days will build muscle-creatine concentrations to a level comparable to that achieved with the whopping 20-gram ingestions. Very importantly, these three-gram per day intakes appear to be associated with very little water retention and weight gain.

Thus, it appears that creatine monohydrate can be a performance-boosting (and legal) supplement for endurance runners. The best way to take it is to simply sprinkle about a half-gram of the stuff on some food (and then of course eat the creatine and comestible) six times per day. Little creatine will be lost in the urine and faeces, creating a very economical intake pattern, little weight will be gained, and the resulting heightened intramuscular creatine-phosphate concentration should have a direct, positive impact on the quality of your high-intensity training sessions. Since intensity is the most potent producer of running fitness, your creatine-boosted sessions should eventually lead to some very nice PBs.

Bear in mind that there’s no need for you to buy ‘special’ creatine. ‘Micronized’ creatine and any commercial creatine product which supposedly can be absorbed more readily offers no special advantages; in fact, as the rate of creatine absorption increases, the urinary losses of creatine become greater.

Jim Bledsoe

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Tags: duathlon, triathlons

Original Cal-Mag Formula – Natural sleeping draught and pain suppressant

Admin — Tue, 16 Mar 2010 07:29:27 +0000

Calcium Magnesium Ratio

The proven ratio used in the Cal-Mag Formula is one part elemental magnesium to two parts elemental calcium.

As the Cal-Mag Formula calls for precise amounts of these elemental substances, some further explanation of these quantities should be given here.

The Cal-Mag Formula is made using the compounds calcium gluconate and magnesium carbonate. Both of these come in white, powdery form. Each is a compound of different substances. In other words, calcium gluconate contains other substances beside calcium; it is not all pure calcium but contains only a percentage of pure elemental calcium. Similarly, magnesium carbonate contains other substances besides magnesium, and includes only a percentage of pure elemental magnesium.

But it is the amount of elemental magnesium in correct ratio to the amount of elemental calcium that is important in the preparation of the Cal-Mag Formula. This does not mean that you use pure magnesium or pure calcium when you make Cal-Mag. Use only calcium gluconate and magnesium carbonate.

Magnesium Carbonate. The desired compound for Cal-Mag, called magnesium carbonate basic, contains 29 % magnesium. (This compound is also sometimes called magnesium alba.)

There are different magnesium compounds with different percentages of elemental magnesium, but using any kind other than that recommended here will give varying amounts of magnesium which will violate the needed ratio of one part magnesium to two parts calcium.

It is magnesium carbonate basic, containing 29 % elemental magnesium which is used in making Cal-Mag and it is essential to ensure that the magnesium carbonate basic which is used is fresh, not old.

Calcium Gluconate: There is only one kind of calcium gluconate compound and 9 % of that compound is calcium, so there is no problem in selecting the correct calcium gluconate compound for the Cal-Mag preparation.

The Cal-Mag Formula

Note, again, that the ratio is one part elemental magnesium to two parts elemental calcium. If one wants to work this out precisely, one can work out the elemental amounts.

The Cal-Mag Formula below has been given the compound amounts:

Put 1 level tablespoon of calcium gluconate in a normal-sized drinking glass.
Add one half level teaspoon of magnesium carbonate.
Add 1 tablespoon of cider vinegar (at least 5 % acidity).
Stir it well.
Add one half glass of boiling water and stir until all the powder is dissolved and the liquid clear. (If this doesn’t occur it could be from poor grade or old magnesium carbonate, or insufficient cider vinegar.)
Fill the remainder of the glass with lukewarm water or cold water and cover.
The solution will stay good for two days.

Make a Palatable Cal-Mag

There is warning regarding Cal-Mag. Variations from the above can produce an unsuccessful mess that can taste pretty horrible. It can be made incorrectly so that it doesn’t dissolve and become the most unpalatable, ghastly stuff anybody
ever fed anybody. Possibly when made incorrectly it is even unworkable.

There is also the factor that one should mix the solution in exactly the correct proportions and approach the dosage on the cautious side, as an overdose of magnesium can cause diarrhea. I doubt, however, that as much as three glasses of
properly mixed Cal-Mag would bring about that condition.

Made correctly, Cal-Mag is very clear liquid, pleasant to take and palatable. Thus the directions should be followed very explicitly, to produce a proper Cal-Mag that is both pleasant to take and beneficial.

Cal-Mag has been found to have added benefit of balancing out the vitamin B1 used on the program, as vitamin B1 taken without calcium can cause serious teeth problems by setting up an imbalance of vitamins and minerals.

Handling Withdrawal

The use of Cal-Mag has been used very effectively during withdrawal to help ease and counteract the convulsions, muscular spasms and severe nervous reactions experienced by an addict when coming off drugs (including smoking).
The success of its application for withdrawal cases by drug rehabilitation centers such as Narconon has now been established. Cal-Mag has been reported as effective in withdrawal from any drug, its effectiveness most dramatically
observable with methadone and heroin cases.

Methadone attacks bone marrow and bones so one usually encounters a severe depletion of calcium in methadone users, characterized by severe pain in joints and bones, teeth problems, hair problems. Getting calcium into the system (in the acidic solution in which it can operate), along with magnesium for its effect on the nerves, helps to relieve these conditions.

It has been reported that with use of Cal-Mag, a person can be withdrawn from methadone anywhere from two weeks to three months faster than without its use. This may apply in withdrawal from other drugs as well.

Since drugs (including nicotine) or alcohol burn up the vitamin B1 in the system rapidly, taking a lot of B1 daily when coming off drugs helps to avoid the convulsions which often attend this deficiency. The B1 must, of course, be flanked with other vitamin dosages to maintain a proper balance of needed nutrients. And, accordingly, sufficient quantities of Cal-Mag are needed, both to prevent created mineral deficiencies and to work its wonders in easing and relieving the agonies accompanying withdrawal.

From 1 to 3 glasses of Cal-Mag a day, with or after meals, replaces any tranquilizer and sleeping draught. It does not produce the drugged effects of these (which are quite deadly).

An Easy Mix Method – Herbal Drink

Order and mix together 77.5 grams magnesium carbonate and 500 grams calcium gluconate.
Put 3 level medicine measures of powder mix and 3 medicine measures of cider vinegar in cup or mug and stir.
Fill cup slowly with boiling water while stirring.
If mixture is not clear, add a little more cider vinegar as it may not have had the required acidity.
Add Rooibos tea bag (or any herbal tea of choice) and sweeten to taste with Stevia powder or liquid.
Drink hot or cold 3 times daily, especially last thing at night to sleep well.
It is a natural sleeping draught and pain suppressant.
Also helps alleviate female PMS, period pains and osteoporosis.
Note: On first taking this, some persons may experience mild flatulence and diarrhea which usually clears after a few days as the body adjusts.

Tags: sport triathlon, triathlons

Sports nutrition – A training strategy for protein consumption

Admin — Sun, 07 Feb 2010 07:19:10 +0000

A comprehensive and well researched article for those who want to optimise their nutrition to maximise performance which could give them the edge over their competition. Mike.

There is more to protein intake than simply eating the right amount

There’s more to protein nutrition than just eating the optimum amount; the timing of consumption and the type of protein selected can both impact on nitrogen balance; and there are a number of nutritional ‘co-factors’ that are either essential or useful in promoting optimum protein metabolism within the body.

This is especially true where carbohydrate is concerned, because building or even maintaining lean tissue mass is an ‘energy-intensive’ process. Increasing protein intake at the expense of carbohydrate can be a bad strategy for athletes engaged in heavy training, because without sufficient carbohydrate the body simply switches to other fuels for energy, and amino acids from protein (particularly the branched chain amino acids, leucine, isoleucine and valine) provide a ready source of energy!

Muscle tissue is a relatively rich source of branched chain amino acids (BCAAs), and tends to undergo breakdown during periods of highenergy demand, when carbohydrate and/or the amino acid pool becomes depleted. Furthermore, carbohydrates stimulate the release of insulin, a highly anabolic hormone, which helps to drive both glucose and amino acids into muscle cells. Any athlete seeking to optimise his or her protein metabolism should therefore ensure a carbohydrate intake commensurate with training volume.

Protein-carbohydrate mixes

The role of carbohydrate in enhancing endurance during long events and accelerating post- exercise recovery is undisputed, and new research (highlighted in PP 194, March 2004) indicates that carbohydrate feeding before and during high intensity exercise can limit the amount of stress hormone release, thereby reducing the risk of post-exercise immune suppression. However, research suggests that protein has a role to play, too. A study on resistance training examined hormonal responses to water, carbohydrate, protein or a carbohydrate/protein mix, given immediately and then two hours after a training session. As expected, those fed the carbohydrate and carbohydrate-plus-protein mix drinks showed an increased insulin response.

However, those fed the carbohydrate-protein mix also showed a modest but significant increase in growth hormone levels, suggesting that protein combined with carbohydrate following resistance training may create a more favourable hormonal environment for muscle growth.

Post-exercise protein feeding seems to be beneficial for endurance athletes also. In a study on 40 swimmers given either water or water-plusglucose during training sessions and then either water, sucrose or a sucrose-plus-milk protein mix after training, the subjects receiving the posttraining sucrose-protein mix exhibited lower levels of creatine phosphokinase (a marker of muscle damage) than the others. Moreover, creatine phosphokinase levels returned to baseline levels more rapidly in this group, indicating that the ingestion of protein with carbohydrate accelerates recovery.

A study on ultra-endurance athletes, published just a few months ago, showed that a carbohydrate-protein mix maintained a positive nitrogen balance during and after a six-hour training session (five hours of cycling and one hour of running), while a straight carbohydrate drink did not.

The consensus of scientific opinion now is that, following intense exercise, athletes should ingest a carbohydrate and protein mix (around 1 gram per kg of body mass of carbohydrate and 0.5g per kg of protein) within 30 min of completing exercise, as well as consuming a high-carbohydrate meal within two hours. This nutritional strategy has been found to accelerate glycogen resynthesis as well as promoting a more anabolic hormonal profile that may hasten recovery.

Research carried out over a decade ago indicated that ingesting a light carbohydrate/ protein snack 30-60 minutes before exercise is also beneficial. In these studies it was shown that 50g of carbohydrate and 5-10g of protein, taken before a training session, could increase carbohydrate availability towards the end of an intense exercise bout and also enhance the availability of amino acids to muscles, thereby decreasing exercise-induced catabolism (breakdown) of protein.

This research appears to be backed up by a very recent study carried out on 15 trained cyclists, who cycled to exhaustion on two rides 12-15 hours apart, the first at 75% and the second at 85% of VO₂max. During the test, riders were split into two groups and given either a 7.3% carbohydrate drink (1.8ml per kg every 15 minutes), or the same drink with protein added at 1.8%. After 7-14 days, the test was repeated and the drink protocol reversed.

The results showed that riders taking the carbohydrate-plus-protein rode for 29% longer than the carbohydrate-only group during the first (75% VO₂max) ride and 40% longer during the second (85% VO₂max) ride! Furthermore, peak levels of creatine phosphokinase were 83% lower when carbohydrate plus protein was taken. Since the carbohydrate plus protein drink contained 25% more calories overall, further studies are needed to see how much of this effect is due to higher energy intake. However, it seems reasonable to assume that a carbohydrate-protein drink taken during training provides for increased protein concentration outside the cell, which can potentially enhance protein synthesis and repair.

The concept of different glycaemic indexes (the rate at which digested carbohydrate is released into the bloodstream as glucose) for different carbohydrates is now well accepted. However, different proteins display different rates of breakdown into their amino acid building block constituents, and hence uptake into the body.

A study into whey protein and casein (two types of protein supplements that are popular with athletes and bodybuilders) examined the speed at which one of the amino acids (leucine) appeared in the bloodstream after ingestion of a meal of each kind of protein (containing identical amounts of leucine). The researchers found that whey led to a dramatic but short-term increase in plasma amino acids, while casein induced a prolonged plateau of moderately increased levels.

They concluded that the differences were probably explained by the slower gastric emptying of casein. Whey protein is a soluble protein whereas casein clots into the stomach, so delaying its gastric emptying. Likewise, soy protein appears to be digested more rapidly than milk protein, resulting in a higher but more transient peak of plasma amino acids.

The implications are obvious: an athlete seeking to supply a post-training or mid-training boost to the amino acid blood pool would be best advised to consume a fast-release protein, such as whey or soy. However, when a prolonged period of recovery is in store (eg at bedtime) a slowerreleasing casein protein drink, such as milk, would be better. Another implication of this study is that, providing a meal or drink supplies the same quantity of the essential amino acids, one type of protein is not necessarily ‘better’ than another. Of more importance is that its release rate is matched to the timing of ingestion.

The situation also appears to be complicated by age. A recent study, which looked at the effects of protein retention in young men (mean age 25 years) fed protein meals containing either slow-releasing casein proteins or rapid-releasing whey proteins, found a greater retention (ie uptake into muscles) after casein. However, when the same researchers studied protein retention in elderly subjects (mean age 72 years), their findings were reversed, with whey protein producing a significantly higher uptake of amino acids than casein.

The researchers surmised that amino acid availability may limit muscle synthesis in older subjects, and that the higher amino acid peaks produced by whey prevented this from happening. The implication seems to be that ingesting fast-releasing proteins mid- or postexercise may be more important for older athletes than their more youthful counterparts.

‘Free form’ amino acids

The process of digestion releases the amino acid building blocks from ingested protein. However, as we’ve seen, this release rate is variable and the process of digestion itself actually consumes energy. This has prompted some investigators to ask whether the use of ‘free form’ amino acids before, during or after training could be a rapid method of providing athletes with optimum amounts of amino acids exactly when they’re needed.

Particular interest has been shown in the branched chain amino acids (BCAAs), which are readily oxidised for energy and therefore in greater demand when energy output is high. In theory, BCAA supplementation might help to minimise protein degradation, thereby leading to greater gains in fat-free mass, or at least minimise lean tissue loss when training volumes are high.

BCAAs and body composition

There is some evidence to support this hypothesis; for example, a study conducted on trekkers at altitude found that taking 10g of BCAAs per day during a 21-day trek increased fat-free mass by approximately 1.5%, while controls on placebo experienced no such change. Meanwhile, another study found that 30 days of BCAA supplementation (14g per day) promoted a significant increase in muscle mass (+1.3%) and grip strength (+8.1%) in untrained subjects.

These findings suggest that BCAA supplementation may have some impact on body composition. Moreover, some recent evidence suggests that BCAA supplementation can decrease exercise-induced protein degradation and/or muscle enzyme release (an indicator of muscle damage), possibly by promoting an anticatabolic hormonal profile⁽. However, despite the persuasive rationale, the effects of BCAA supplementation on short- and long-term exercise performance are somewhat mixed, with some studies suggesting an improvement and others showing no effect. More research is needed, therefore, before firm conclusions can be drawn.

Having said that, there is good evidence that BCAAs administered during training can reduce the perception of fatigue, while improving mood and cognitive performance. A study on seven male endurance-trained cyclists with depleted glycogen stores examined the effects of BCAA supplementation (versus placebo) on mental fatigue and perceived exertion. The subjects exercised at a work rate corresponding to approximately 70% VO₂max for 60 minutes, followed by another 20 minutes of maximal exercise.

During the 60-minute section, the subjects’ ratings of perceived exertion were 7% lower and mental fatigue 15% lower when they were given BCAAs. In addition, cognitive performance in the ‘Stroops Colour Word Test’ performed after exercise was improved when BCAAs had been ingested during exercise. Interestingly, however, there was no difference in physical performance in the final 20-minute segment of the ride between the placebo and BCAA groups; the amount of work performed during this section was the same regardless of which supplement was taken.

These findings on BCAA supplementation, mental fatigue and perceived exertion were replicated in a study on runners given carbohydrate-plus-BCAA drinks or carbohydrateonly drinks (placebo) during a 30k cross-country run. Subjects on BCAAs improved their postexercise performance in the above-mentioned Stroops test by an average of 3-7% compared with those on placebo. The BCAA group also maintained their performance in two more complex mental tasks (shape rotation and figure identification) after exercise, while the placebo group showed a 25% and 15% reduction respectively in these tasks.

Researchers believe that this cognitive effect may be due to the ability of BCAAs to compete with and therefore reduce the uptake of another amino acid, tryptophan, across the blood-brain barrier and into the brain. Tryptophan is the precursor to a brain neurotransmitter called 5- hydroxytryptamine (5-HT – more commonly known as serotonin), which is involved in fatigue and sleep and is believed to contribute to the development of central/mental fatigue during and after sustained exercise. During exercise, the concentration of tryptophan in the blood relative to other neutral amino acids seems to rise. But supplementing with BCAAs seems to help block this effect, which would, in turn, reduce levels of 5- HT in the brain.

Is leucine a ‘special-case’ BCAA?

Leucine is the most studied of the BCAAs, partly because leucine and its metabolites have been reported to inhibit protein degradation ⁽²²⁾. In the body, leucine accounts for about 4.6% of all amino acids and is involved in many important roles in the body, such as regulating protein metabolism by inhibiting degradation and stimulating synthesis .

Of particular interest is the fact that leucine can be oxidised to a compound known as acetylCoA in muscles at a higher rate than the other BCAAs (valine and isoleucine). This is important because acetylCoA is an ‘entry point’ into the citric acid cycle, one of the main energy-producing pathways in the body, and itself the gateway to aerobic metabolism, which explains why the demands for leucine rise substantially during periods of high energy expenditure. Studies have also shown that leucine oxidation is increased under catabolic conditions, such as depleted muscle glycogen.

Some researchers believe that the current leucine requirement, set at 14mg per kg of body weight per day, should be increased to 30mg in people who regularly participate in endurance activities. This argument is supported by research that suggests endurance athletes can actually burn more leucine than they take in through the RDA of protein.

One of the best-known leucine metabolites is a compound called ß-hydroxy ß-methylbutyrate, Is leucine a ‘special-case’ BCAA? more commonly known as HMB, which is popular with bodybuilders and athletes as a muscle/strength building supplement. But what is the evidence that it actually works? Recent research indicates that 1.5-3g per day of HMB supplementation can increase muscle mass and strength, particularly in untrained subjects beginning training and in the elderly. The muscle mass gains in these studies are typically 0.5-1kg greater than for controls during 3-6 weeks of training.

There is also recent evidence that, in athletes, HMB may reduce the catabolic effects of prolonged exercise. In one study, 13 runners were split into two groups, one taking 3g of HMB per day and the other a placebo. Both groups continued with their normal training for six weeks, after which they completed a 20k run. Before and after the run, creatine phosphokinase and lactate dehydrogenase levels (both measures of muscle damage) were measured, with the HMB group showing much smaller increases in both than the placebo group, indicating significantly reduced muscle damage.

However, the long-term effects of HMB supplementation in athletes are less clear. Most studies conducted on trained subjects have reported non-significant gains in muscle mass(34-36), but further research is needed to clarify whether HMB really does enhance training adaptations in athletes.

Essential amino acids

The BCAAs comprise just three of the nine essential amino acids (EAAs), the other six being histidine, lysine, methionine, phenylalanine, threonine and tryptophan. As mentioned, essential amino acids have to be obtained from the diet because they can’t be synthesised in the body from other amino acids. Although the six ‘straight chain’ EAAs are not so readily utilised as fuel, some researchers believe that giving all nine EAAs in a free form (ie as a mix of separate amino acids, not as protein), and in ratios that reflect the amino acid composition of muscle protein, is more beneficial for muscle protein synthesis than giving BCAAs alone.

In recent studies, scientists in Texas have found that ingesting 3-6g of EAAs before and/or after exercise stimulates protein synthesis. Moreover, this stimulation appeared to increase in a dose-dependent manner until plasma EAA concentrations are doubled, and was maximised when EAAs were administered to maintain this doubled concentration over a three-hour period. Adding carbohydrate seemed to enhance this protein synthesis, probably through the anabolic effect of insulin.

Although there has been very little research on EAA ingestion by athletes, studies on resistance training in healthy adults seem to confirm the potential benefits of EAAs; for example, muscle protein synthesis was increased 3.5-fold when 6g of a mixture of EAAs was given along with 35g of carbohydrate after resistance exercise.

In another study, three men and three women resistance trained on three separate occasions and then consumed, in random order, one of the following:

a 1 litre solution of mixed amino acids containing both essential and nonessential amino acids (40g);
a solution containing only essential amino acids (40g);
placebo.

Net muscle protein balance was negative after ingesting placebo but positive to a similar magnitude for both the mixed and essential amino acid drinks. The researchers concluded that: ‘it does not appear necessary to include nonessential amino acids in a formulation designed to elicit an anabolic response from muscle after exercise’.

A comprehensive protein strategy

Given the above findings, what reasonable steps can an athlete take to optimise his or her protein nutrition? Below is a ‘protein checklist’, which crystallises these findings into dietary recommendations:

Ensure an adequate intake of dietary protein – ie a minimum of 1.5g of high-quality protein per kg of body weight per day. Power/strength athletes, or those engaged in intense training, should consider increasing this to 2g per kg per day;
Ingest protein-carbohydrate drinks after exercise rather than protein alone. Ideally, consume a drink made up of about 1g per kg of carbohydrate and 0.5g per kg of protein within 30 minutes of training, and eat a high-carbohydrate meal within two hours;
Consume a light pre-exercise snack: 50g of carbohydrate and 5-10g of protein taken before a training session can increase carbohydrate availability towards the end of an intense exercise bout and also increase the availability of amino acids to muscles. However, make sure your snacks are low in fat to allow for rapid gastric emptying!
Use protein/carbohydrate drinks during very long events: a solution containing 73g carbohydrate and 18g protein per litre, consumed at a rate of 1ml per kg of body weight per minute, may delay the onset of fatigue and reduce muscle damage;
Consume quick-digesting proteins such as soy and whey immediately after training: this may be especially important for older athletes;
At other meals, consume a mix of proteins in order to promote a more sustained release of amino acids into the body;
Adding BCAAs to your normal protein intake may be useful for athletes undergoing prolonged or heavy training, and this may be particularly true for events/sports requiring large amounts of mental agility and motor coordination;
HMB supplementation, at 3g per day, may be a useful additional strategy for novice athletes, or those returning to training after a layoff;
Essential amino acid blends taken 1-3 hours after training may promote additional muscle protein synthesis, although this hypothesis is not proven in athletes;
Don’t forget to ensure that your overall diet is of high quality and as whole and unprocessed as possible: this will ensure adequate intakes of other nutrients essential for protein metabolism, such as zinc and the B vitamins.

Andrew Hamilton

References

J Appl Physiol, 2003; 548P, 98
J Appl Physiol, 2003; 94:1917-25
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This article was taken from the Peak Performance newsletter, the number one source of sports science, training and research. Click here to access these articles as soon as they are released to maximise your performance

Tags: triathlon, sprint triathlon

Sports Nutrition – Does sodium bicarbonate supplementation improve performance?

Admin — Tue, 26 Jan 2010 07:36:43 +0000

Joe Friel in his book “Going Long” talks about the use of potassium bicarbonate to reduce blood acidity as well. His motivation for this revolves around the fact that our blood increases in acidity with age, and the use of this supplement would reduce aging symptoms. From the evidence in this article using sodium bicarbonate to reduce blood acidity for improved sports performance, we have in fact a double benefit. Mike.

New research suggests taking sodium bicarbonate before you train boosts endurance levels

It’s been used in baking for years and briefly found favour with athletes, but as Keith Baar and Andy Philp explain, new research suggests that taking sodium bicarbonate before you train really could lead to better endurance performance…

During intense training, our muscles produce a substance called lactate and hydrogen ions (acid) faster than we can use or get rid of them. The result is a build up of these by-products in the exercising muscle. People have long believed that this increase in acid and lactate is a direct cause of fatigue. However, scientists still argue over this point despite over a century of investigation.

Our bodies have a number of protective mechanisms that try to prevent the build up of acid. One of the most important of these is bicarbonate, which is alkaline – ie it helps neutralise acid. Bicarbonate is not only used as a raising agent in baking, but is also made throughout our bodies. One of the biggest bicarbonate producers is the stomach, where bicarbonate is made as a by-product in the process of making our digestive juices. After we eat, the rush to make stomach acid results in an increase in bicarbonate released into the bloodstream. This ‘alkaline tide’ is what makes us feel sleepy after a meal – not what will help us improve performance.

Bicarbonate in the body

During exercise, bicarbonate is initially made as a way to get rid of the carbon dioxide (CO2) produced by our muscles. The increased requirement for ATP to power our muscles results in an increase in CO2 production as a by-product of the breakdown of fats and carbohydrates. In the blood that feeds the muscle, CO2 and water (H2O) are converted to HCO3- (bicarbonate) and H+ (acid) by red blood cells using the enzyme carbonic anhydrase. At the lung, the reaction is reversed and the CO2 and water are released in the breath. This allows us to exhale the waste and maintain the correct acid/alkaline balance in our muscles.

For years, this was believed to be the reason that the lactate threshold and the ventilatory threshold coincided. The idea was that, at our lactate threshold, oxygen delivery to the muscles was insufficient and this resulted in a shift towards energy production without oxygen and the production of lactate and hydrogen ions. Since acid production was turned on, the increase in acid would mean the process above was accelerated, resulting in a sharp rise in ventilation.

While the theory of the relationship between the lactate and ventilatory thresholds makes sense, it doesn’t appear to be right. Newer studies show that oxygen delivery to the muscle is not limited during sub-maximal exercise, so that a lack of oxygen in our muscle cells isn’t what causes lactate production(1). What we really think causes both the lactate and ventilatory thresholds is a rise in the ‘fight or flight’ hormone called adrenaline, and a change in which muscle fibres we use. As the exercise intensity rises, we start to use more type II glycolytic muscle fibres. These fibres produce more lactate than type I or type II oxidative fibres, resulting in increased lactate accumulation in the blood.

At the same time, there is a sharp rise in adrenaline. This is because as the intensity of exercise increases it becomes a greater stress on our body and this activates the flight or flight response: releasing adrenaline. The rise in adrenaline causes our muscles to break down stored carbohydrate (glycogen) faster and decreases blood flow to the liver and kidneys (where lactate is normally removed from the blood), contributing to the accumulation of lactate. Adrenaline also directly increases our respiratory rate, contributing to the ventilatory threshold.

Bicarbonate and performance

No matter their cause, lactate and ventilatory threshold play a significant role in performance. The higher that we can get our speed/power at lactate threshold, the better our performance will be. Therefore, if we can focus our training on increasing speed/power at lactate threshold, we can maximise our performance adaptation.

One way might be to boost the amount of bicarbonate that we have in our blood on the day of the big event. The extra bicarbonate should buffer the acid our muscles produce and therefore increase the intensity we can maintain before lactate begins to build up in our blood.

People have tested the effects of bicarbonate on performance for over 75 years, on the premise that acid accumulation limits our endurance performance.
In 1931, scientists showed that drinking a solution that contained baking soda (sodium bicarbonate or bicarb) prior to exercise could improve running performance (2). These experiments were confirmed 2 years later, but a huge amount of conflicting research in the following 75 years has made people question whether bicarb can really be used as an ergogenic aid.

Beyond the scientific uncertainty, one of the biggest concerns with using bicarb on the day of performance is that drinking large amounts of baking soda can cause severe intestinal distress (read bloating, nausea and diarrhoea). Since these types of complications are the last thing anyone wants to have to deal with on the day of competition, a lot of athletes have quite understandably shunned the use of bicarb (but see box 1 for tips on decreasing intestinal problems when taking bicarb).

Bicarb training research

While the effects of bicarb on the day of the competition are uncertain and the potential negative effects on the gut might make an athlete unlikely to use bicarb for an important event, there might be good reasons to use bicarb during training. In the last three years, two studies have come out showing that taking bicarbonate during training improves performance.

In the first study, 16 moderately trained women exercised three times a week for eight weeks(3). One group drank a bicarb solution at 90 and 30 minutes prior to performing each high-intensity interval training session (containing 0.2g of bicarb per kilo of bodyweight) while group two drank a similar tasting salt solution.

In weeks one and two, each subject performed six to nine 2-minute intervals on a bike at 140% of their initial power at lactate threshold. The number of intervals and the relative intensity increased every second week until they were performing twelve 2-minute intervals at 160% of the power at lactate threshold in week seven. For week eight, the number of intervals was decreased to six to nine again, but the power was increased to 170%. Before and after training the subjects performed both a graded exercise test for peak VO2 and a time to fatigue test to measure endurance.

In the group that took the bicarb, the alkalinity, the concentration of bicarb, and the amount of lactate in the blood was higher during each training session. This tells us that the drink was absorbed and had the effect of making the blood less acidic. After the 8-week training programme, both groups improved their peak oxygen uptake (VO2) by approximately 18%. However, the group that took bicarb before each training session improved their power at lactate threshold 9.6% more than the group that took the saline solution.

As discussed above, power at lactate threshold is one of the most important parameters for determining endurance performance. Therefore, it was not surprising to see that the bicarb group showed a 41% greater improvement in time to fatigue (see figure 1). While this isn’t a direct measure of performance, the increased endurance and improved power at lactate threshold are strongly associated with better performance.

After discovering that drinking bicarb during training improved performance in humans, some of the same scientists went on to try to determine how bicarb might be exerting its positive effects (4). To do this, they switched from people to rats, allowing a more controlled experiment and detailed analysis of muscle adaptation to training. They split the rats into three groups:

A control that didn’t exercise or take bicarb;
An exercise group that drank water;
An exercise group that drank a bicarb solution 30 minutes before exercise.

Like the human subjects in the first study, the rats increased their training from six to twelve 2-minute intervals, but with a running speed increase of 37 to 52 metres/min over the five weeks of the study.

At the end of training, the bicarb-drinking group had increased the number of mitochondria in one of their running muscles 7.5% more then the water group even though the animals did exactly the same amount of work. The authors of the study also found that the bicarb group increased the production of the transporter protein called MCT4, which helps remove lactate from the muscles (see figure 2). The fact that there was a greater rise in mitochondria tells us that adding baking soda to your training schedule would result in better performance even if you were to do no more work.

When we saw this data, we were excited by the fact that simply adding bicarb increased the number of mitochondria in muscle. The fact that they only measured this in a ‘slow’ muscle was interesting because we think that the greatest effect would be in fast twitch muscle where the ability to increase mitochondria is the strongest. Since the number of mitochondria in our fast muscles is one of the best determinants of speed/power at lactate threshold, we wondered whether the improved performance was due to a direct effect of bicarb on our mitochondria.

To study this question, Andy Philp performed a series of experiments on isolated muscle cells. The logic is that if bicarb is exerting its benefits on muscle cells and not the whole body, by just feeding the cells bicarb, we should see the same effects that the researchers above saw in people and rats.
So, Andy set up a (as yet unpublished) cells study in which one cell culture got a salt solution and the other got a solution containing about the same amount of bicarb as would have been circulating in the human study (3). After three days of treating the cells in this way, we saw an increase in the amount of mitochondrial protein in the cells of approximately 50% (see figure 3).

The reason for this increase in mitochondrial protein appears to be that bicarb is able to directly turn on a regulator of the number of mitochondria in our cells. The amount of this protein, PGC1alpha, is one of the most important factors in making new mitochondria. Simply adding bicarb to the cells resulted in a 5-fold increase in PGC1alpha. This increase in PGC1alpha is almost identical to what is seen after endurance exercise. These data tell us that simply taking bicarb may provide some of the same effects as exercise!

The other interesting findings from this study are that the cells that got the bicarb treatment consumed more energy at rest, they were better able to transport glucose, and they contained more of the glucose and lactate transporters. This tells us that after three days treatment with bicarb, the cells looked more like those in the muscles of an endurance athlete, because endurance athletes have a higher resting metabolism and are better able to take up lactate and sugar from the blood.

The last question that remained was whether the adaptation is a direct effect of the bicarb or whether it is an effect of increasing the alkalinity around the cells. To study this question, Andy employed another popular agent used to control acid/alkaline balance, called sodium citrate. When Andy did the same experiments using citrate, he saw a small increase in PGC1alpha, but not as much as during the bicarb experiments. So, this means that it’s the bicarb that acts directly on our muscle cells to increase mitochondria rather than any change in acid/alkaline balance.

Conclusions

Drinking baking soda solution before exercise means that there is high bicarb concentration in the blood during exercise. Doing high intensity intervals directs that blood to the ‘fast twitch’ muscle fibres (that do a lot of the work at high intensity). The bicarb is taken up in these fast fibres and acts to increase the mitochondrial controller (PGC1alpha). The increase in PGC1alpha signals these fast fibres to make more mitochondria. As discussed above, power at lactate threshold reflects the amount of mitochondria we have in our fast twitch muscle fibres. Therefore, by targeting these fibres with training and nutrition, we can improve their adaptation and, by extension, our performance.
So using sodium bicarbonate during training could be an inexpensive but powerful tool to add to your training regime. It would have a positive effect at any point in training, but the biggest effect on performance will be when you are trying to improve speed/power at lactate threshold using high intensity workouts.

Keith Baar runs the functional molecular biology laboratory at the University of California.

Andrew Philp is a postdoctoral fellow at the University of California and has performed all of the experiments on the effects of bicarb on muscle mitochondria. Both authors are scientific consultants with the English Institute of Sport and British Cycling

References

1. J. Appl. Physiol. 1998 85: 627-634
2. J Clin Invest. 1931 9: 601-13
3. J Appl Physiol. 2006 101: 918-25
4. Am J Physiol Endocrinol Metab. 2007 293: E916-22

Tags: sprint triathlon, wetsuit

Nutrition – The role of protein in sports performance

Admin — Thu, 29 Oct 2009 14:11:27 +0000

This is an absolute MUST read! The best article I have ever read on the subject. It is based on proven scientific research (references included) without any commercial hype, and dispels all the common myths. – Mike

How much protein do athletes need and how safe are high-protein diets?

Protein is not just an essential nutrient, but the largest component in the body after water, typically representing about 15% of body weight. Most of this protein mass is found in skeletal muscle, which explains the importance of protein to athletes. However, proteins also play an important role in the following:

Transport and storage of other nutrients;
Catalysing biochemical reactions;
Control of growth and differentiation;
Immune protection;
Providing our bodies with structural integrity.

Although the basic biochemistry and functional roles of protein in the body have long been understood, there’s still a huge amount of mythology and confusion surrounding protein nutrition, especially where athletes are concerned. This is partly because of general misconceptions about basic protein metabolism and partly because new research continues to throw up surprises about exactly what constitutes optimum protein nutrition!

Figure 1, below, provides a brief overview of protein metabolism. The protein we eat is made up of around 20 amino acid ‘building blocks’. The process of digestion breaks down dietary protein into its constituent amino acid building blocks, which can then be absorbed into the body and reassembled to make various kinds of human protein, such as muscle, connective tissue, immune proteins, and so on.

Figure 1: overview of protein metabolism

However, it is important to understand that protein metabolism is in a constant state of flux; although muscle and other tissues contain a large amount of stored protein, this protein is not ‘locked away’. When dietary amino acids are insufficient, tissue protein can rapidly be broken down back to amino acid building blocks, which are then used to replenish the ‘amino acid pool’, a reservoir of amino acids that can be drawn upon to support such vital functions as energy production or immune function. This explains why muscle mass is often lost during times of stress, disease and heavy training loads, or poor nutrition.

Conversely, when dietary amino acids are in plentiful supply and other demands for protein are low, tissue protein synthesis can become the dominant process. The overall control of protein turnover – ie whether the body is in a state of anabolism (building up) or catabolism (breaking down), also known as positive or negative nitrogen balance – is governed by hormonal factors, caloric intake and availability of amino acids, particularly of the nine ‘essential’ amino acids that cannot be synthesised in the body and therefore have to be obtained from the diet.

Maintaining optimum protein status

An athlete has to move his or her body to perform, and this requires the muscles to generate force to accelerate body mass. As a rule of thumb, the greater an athlete’s power-to-weight ratio, the faster he or she can move, and (to a lesser extent) the longer he or she will be able to maintain any given speed of movement. Since all force and movement is generated by muscles, most power athletes benefit from maximising muscle mass and strength, while minimising the amount of superfluous body mass – ie fat.

And while out-and-out muscle strength is less important for endurance athletes, maintaining sufficient muscle mass is critically important, not least because high training volumes are known to increase the rate of protein oxidation from the amino acid pool, potentially leading to delayed recovery, a loss of muscle mass and consequent loss of power, and increased injury risk.

Given that athletic training is known to increase the demands on the amino acid pool, many athletes, particularly bodybuilders and strength athletes, adopt high-protein diets to maintain a positive nitrogen balance, or at least prevent catabolism and loss of muscle tissue. However, even today there remains much debate about how much protein athletes really need to optimise and maintain performance.

Protein v carbohydrate

There are other questions too. For example, should any extra protein be ingested at the expense of carbohydrate, the body’s preferred fuel for high-intensity training? And what about the possible health implications of high-protein diets, about which health professionals often express concerns?

Until recently the protein requirements of athletes were thought to be similar to those of sedentary people, and athletes were advised that they need only consume the recommended daily amount (RDA) of protein (currently set at 0.8- 1.0g of protein per kg of body weight per day) to maintain proper nitrogen balance. For a 70kg athlete, this would equate to 56-70g per day.

However, research over the past decade has indicated that athletes engaged in intense training actually need to ingest about 1.5-2 times the RDA in order to maintain a positive protein balance^(1-5). This equates to 105-140g of protein per day for a 70kg athlete, which is equivalent to three to four medium-sized chicken breasts or 13-20oz of canned tuna per day! There is also evidence that training at altitude imposes an even higher demand for protein – perhaps as much as 2.2g per kg per day⁽⁶⁾.

Unfortunately, these more recent findings on protein needs have not yet become widely accepted by some of the powers that be. For example, the UK’s Food Standards Agency website (in its section on sports nutrition) simply states that protein is important in the diet, especially ‘if you’re trying to build muscle’. It goes on to advise: ‘Try not to eat more protein than you need because your body won’t use it to build muscle. Instead it converts excess protein to fat, which is then stored, so try to make sure your protein intake is just right for your needs.’ However, it never actually states what those needs are.

Meanwhile, the EU’s Scientific Committee on Food recently acknowledged that the increased training loads and energy expenditure of athletes can increase protein requirements, and now recommends that their protein intake should comprise around 10-11% of total energy intake⁽⁷⁾. For our mythical 70kg athlete, burning 3,000, 4,000 or even 5,000kcal per day (quite easily achieved with two-plus hours of vigorous training at or above 75% VO₂max per day), this equates to just over 75, 100 or 125g of protein per day respectively.

Although foods like breads, cereals and legumes contain significant amounts of protein, which can add to that contributed by high-protein foods, such as meat, fish, milk and eggs, larger athletes, or those engaged in high volumes of training, may struggle to include the increased amounts of protein now recommended in a ‘normal’ diet; indeed, a number of nutritional surveys have indicated that protein insufficiency may be a problem for certain groups of athletes, including runners, cyclists, swimmers, triathletes, gymnasts, skaters and wrestlers⁽⁸⁾.

Forty years ago, it was protein that dominated the thoughts of power athletes and bodybuilders. Employing the simple logic that muscles are made of protein, and that to build muscle you need lots of protein, steak-and-egg diets were the order of the day! But as the importance of carbohydrates in supplying energy and driving the insulin system (the most anabolic hormone in the body) became clearer, the emphasis gradually shifted.

This shift in emphasis was encouraged by an appreciation of the health benefits of dietary fibre present in unrefined carbohydrates, and also by research suggesting that very high protein intakes simply resulted in increased protein oxidation, imposing an additional load on the liver and kidneys. A scientific consensus began to form around the notion that diets containing substantially more than 1.0g of protein per kg per day were not only wasteful but potentially harmful, increasing the risk of kidney and liver problems, cardiac disease and even loss of bone density.

However, the recent meteoric rise in popularity of high-protein diets, such as Zone and Atkins, for slimmers has ignited a fierce debate about the safety and efficacy of high-protein diets, which is also relevant for athletes who routinely consume high-protein diets. In 2001, the American Heart Association’s nutrition committee published a statement on dietary protein intakes, claiming that: ‘Individuals who follow these [high-protein] diets are at risk for potential cardiac, renal, bone and liver abnormalities overall’⁽⁹⁾.

If you examine the scientific literature, it is hard to see how this consensus, linking high protein intakes to increased health risks, has become so widespread. In a recent meta-review of the literature, Finnish scientists searched for any evidence supporting the hypothesis that high protein diets, containing two to three times the current RDA for protein, increase the risk of a number of health conditions – and drew a big fat blank⁽¹⁰⁾. They concluded that:

There is no evidence to suggest that (in the absence of overt disease) renal function is impaired by high protein diets;
Far from reducing bone mineral density, high-protein diets may actually increase it;
Such diets are associated with lower not higher blood pressures.

These conclusions have also been confirmed by other researchers; healthy athletes should not, therefore, be dissuaded from increasing their protein intake to up to three times the RDA level if they so wish.

High-protein diets and hydration

There’s a fairly linear relationship between protein intake and urea production, which means that high protein diets increase the amount of urea the kidneys have to excrete. With this elevated production of urea comes an increase in the obligatory water requirement of the kidneys to do their job, and that in turn has raised the question of whether athletes (whose fluids needs are already increased) on high-protein diets are at increased risk of dehydration.

To answer this question, scientists at the University of Connecticut compared the hydration levels of athletes consuming low (0.8g per kg per day), medium (1.8g) and high (3.6g) protein diets, each containing the same number of calories⁽¹¹⁾. Analysis of the results showed that, while there were significant increases in urine and plasma urea on the high-protein diet, the effects of increasing dietary protein on fluid status was minimal.

Moreover, to date there have been no studies conclusively demonstrating that increased protein intake leads to a loss in total body water. However, the researchers pointed out that the subjects in their study probably consumed enough water to meet any increased requirement, which explains – at least in part – why their hydration status was not compromised. They also concluded that more research is needed. In the meantime, however, it seems prudent to recommend that all athletes on high-protein diets should drink plenty of extra fluid, especially in warm conditions.

For many athletes, power-to-weight ratio is more important than outright power for optimum performance, and this explains why reducing excess body fat is often beneficial. New evidence is now emerging that high-protein diets might actually help in this process. Although research indicates that, providing the same number of calories are eaten, the relative proportions of protein and carbohydrate in the diet do not affect the amount or composition of weight loss in a reduced calorie regime^(12-14), these ratios do affect appetite, with subjects tending to be more hungry on higher carbohydrate intakes and less hungry on higher protein intakes.

More generally, scientists now believe that diet composition strongly affects ad lib energy intake, with both laboratory and free-living studies highlighting protein as a more satiating macronutrient than carbohydrate or fat⁽¹⁵⁾. This theory is supported by studies indicating that subjects consuming high-protein (more than 20% protein by energy) diets consume less overall than those on low-protein diets^(16,17). The exact mechanisms are as yet unclear, but probably involve hormonal and chemical changes in regions of the brain known to be associated in hunger and appetite control.

Protein and weight loss

In one of the studies mentioned above⁽¹⁷⁾, 13 obese men were split into two groups and fed lowcalorie diets. One group received a high-protein diet (45% protein, 25% carbohydrate and 30% fat) and the other a high-carbohydrate diet (12% protein, 58% carbs and 30% fat). Not only was weight loss greater in the high-protein group but basal metabolism decreased less than in the highcarb group, suggesting that the high-protein diet was able to offset the loss in lean body mass (basal metabolism being a function of lean body mass) that normally occurs while dieting.

No studies of this type have been carried out on athletes, but it seems likely that high-protein diets have something to offer athletes seeking a reduction in body fat while conserving muscle tissue. While high-protein/low-carbohydrate diets of the type described above would not contain sufficient carbohydrate to permit normal training, our mythical 70kg athlete, consuming a 25% protein diet on a mildly calorie-restricted diet of 2,500kcals per day, would be consuming around 600kcal of protein, or 150g, a day. This is well within the ‘safety zone’ of two to three times the RDA (0.8-1.0g per kg per day) yet with a sufficiently high protein content to exert an increased satiation effect.

Moreover, the athlete would still be able to consume up to 50% carbohydrates (1,250kcal per day, sufficient for moderate training volumes), while consuming enough calories (25%) from fat to meet essential fat requirements. However, athletes need to remember, given the importance of carbohydrate for energy requirements, that even this regime would contain insufficient carbohydrate for higher-volume training and competition phases!

In summary, there is good evidence that athletes need a plentiful supply of protein in their diets and that, contrary to previous recommendations, they do need substantially more protein than their sedentary counterparts – at least 50% and possibly up to 120% more. For a 70kg athlete, this can mean up to 150g of pure protein per day.

However, the role of carbohydrates in supplying energy for fuel and recovery remain as important as ever, which means the diet must contain high-quality, low-fat sources of protein in order to enable adequate carbohydrate intake without an overall excess of calories. Simply assuming that because you eat more food than the average person you’ll be consuming adequate protein is not good enough!

There is no evidence that routinely exceeding the recommended protein intake has any additional benefits on nitrogen balance, unless this extra protein is consumed as a protein/ carbohydrate drink before, during or after training – something we’ll tackle in the next article (see below). However, there is evidence that even higher protein intakes may help suppress appetite, control hunger and reduce lean tissue loss during restricted calorie routines, which may be useful for athletes needing to reduce or maintain body weight, although such diets are not really compatible with high-volume training routines.

Finally, despite what you may have read elsewhere, healthy athletes can rest assured that high protein diets containing up to three times the current RDA for protein are perfectly safe, although it is important to remain well hydrated on such diets.

Andrew Hamilton

References

J Appl Physiol 1992;73(2):767-75
J Appl Physiol 1988;64(1):187-93
J Appl Physiol 1992;73(5):1986-95
Curr Opin Clin Nutr Metab Care 1999;2(6):533-7
Sportscience 1999. Available: www.sportsci.org/jour/ 9901/rbk.html;3(1)
Butterfield G (1991). Amino acids and high protein diets. In Lamb D, Williams M (editors), Perspectives in exercise science and sports medicine, vol 4; Ergogenics, enhancement of performance in exercise and sport (pages 87-122). Indianapolis, Indiana: Brown & Benchmark
EU Scientific Committee on Food, 2004, Working Document – 20 April. Available: www.food.gov.uk/mult imedia/pdfs/foodsport workdoc.pdf
Sports Nutrition Review Journal 2004; 1(1):1-44
Circulation 2001; 104:1869-74
Sports Nutrition Review Journal 2004; 1(1):45-51
Presentation by WF Martin at Experimental Biology meeting, April 2002 New Orleans, USA
Am J Clin Nutr 1996; 63, 174-178
Diabet. Care 2002; 25, 652-657
N Engl. J. Med 2003; 348, 2074- 2081
Eur J Clin Nutr 1996; 50, 418-430
Int J Obes Relat Metab Disord. 1999; 23, 528-536
Int J Obes Relat Metab Disord. 1999; 23(11), 1202-6

Sports Drinks – Recovering with hypotonic, isotonic and hypertonic drinks

Admin — Fri, 23 Oct 2009 18:52:46 +0000

Never fully understood this stuff until I read this article, which also explains why it may not be a good idea to only drink plain water after exercise in an effort to cut carbohydrates for weight loss – Mike

The importance of post-exercise rehydration

Athletes at all levels often train more than once a day, which means they need to be able to make a rapid recovery between sessions. Most people who take their training seriously are now aware that ingestion of fluids is crucial to maintaining performance and aiding recovery. But the choice of drink can be critical. So which is best, plain water or a specially-formulated sports drink?

To answer that question we need to understand how water is absorbed and used by the body.

The rate at which your body absorbs water depends on a number of factors, one the the most important being the composition of the fluid ingested. It is the concentration of particles such as carbohydrate, sodium and, to a lesser extent, potassium that dictates the rate of absorption in the small intestine. As a rule, the higher the carbohydrate content of a drink the slower the rate of fluid uptake.

* Hypotonic drinks are dilute carbohydrate electrolyte solutions which are less concentrated than body fluids and are therefore rapidly absorbed by the body. They begin the rehydration process while simultaneously helping to replenish carbohydrate energy reserves. No proprietary versions of such drinks are currently available on the UK market since an Umbro product was withdrawn;

* Isotonic drinks have a similar carbohydrate electrolyte concentration to the body’s own fluids. They are best used later in the recovery process to boost energy intake while still encouraging fluid uptake during the final stages of rehydration. Proprietary brands include Liquid Power, Isostar and Lucozade Sport;

* Hypertonic drinks are solutions with a higher carbohydrate electrolyte concentration than body fluids. In general these types of drinks contain large amounts of carbohydrate and are therefore best used as energy supplements during periods of heavy training, when energy expenditure is likely to be high. Again, no proprietary versions are available in the UK, although you can make an isotonic drink hypertonic by making it up in a more concentrated form.

If you prefer to drink water alone after exercise, it is possible to achieve adequate rehydration if solid food which replaces lost electrolytes is consumed at the same time. If this is not possible, some form of electrolyte solution is essential.

This does not mean you should never drink water after exercise – just that you need to take account of your levels of fluid and electrolyte losses. Where losses are high and large volumes of fluid need to be consumed in a short period, it is important to consume sodium in combination with fluids if fluid balance is to be achieved and maintained.

Ian Carlton

Sports Supplements Guide

Admin — Wed, 07 Oct 2009 06:07:21 +0000

There is an awful amount of erroneous or exaggerated data on sports supplementation, much of which is promoted by commercial interests simply touting their latest products. This is a no BS article based on independent scientific research and which offers excellent advice you can trust – Mike.

How many of these fancily packaged and extravagantly advertised products actually work?

In recent years, there’s been an explosion in the quantity and types of sport supplements available and the sports supplement industry is now estimated to be worth a staggering 15 billion US dollars a year. But how many of these fancily packaged and extravagantly advertised
products actually do what they say on the tub or sachet?

More importantly, are they worth parting with your hard-earned cash for, or are they nothing more than modern witchcraft? In this article, we’re going to look at the main product types out there, explain how they’re supposed to work and how effective they’re likely to be.

First things first

Although it’s true that some sports supplements can help you maximise the gains from your workout, the fact is that no amount of supplementation can substitute for a poor diet – all you’ll achieve is very expensive urine and a severely depleted bank balance. Therefore, before you even begin to think about using sports supplements, you need to ensure you’ve sorted out your dietary basics.

Supplement basics

Before you even consider using sports supplements, you need to ensure that your dietary basics are right. Don’t fall into the ‘performance in a bottle syndrome’, and delude yourself that a junk diet is OK so long as you’re taking fancy and expensive supplements. Many of the naturally-occurring, performance-giving substances in food have yet to be properly identified and aren’t found in even the most advanced supplements, no matter how exotic. Then there’s cost. Sports supplements aren’t cheap; could that money be better spent on increasing the quality of your diet in the first place?The bulk of your diet should be comprised of whole, natural unprocessed foods, rich in unrefined carbohydrates (to fuel exercise), and high-quality fruits and vegetables, with minimal intakes of refined, processed, sugary or fatty foods. Proper hydration is crucial too, and you should be drinking plenty of fresh water.Any supplementation should be carefully targeted to your individual needs. For example, if moderate-intensity aerobic exercise is your main fitness pastime, there’s little benefit in shovelling down bucketloads of creatine, which only helps boost short-term, high-intensity energy pathways. Beware of exotic and fancy claims: evidence for the efficacy of many so-called wonder supplements is sparse. If the claims sound too good to be true, they probably are.

Finally, don’t think that even with the perfect diet and the best sports supplements, you’ll notice the benefits if your training programme is not right and you don’t allow yourself adequate recovery.

But let’s assume you’ve got your diet sorted, are training hard, have it all planned out and you want to make the most of your efforts. Which sports supplements should you consider using and what benefits could they offer? The answer depends very much on your training, your sport and your exercise goals. Endurance activities such as running and cycling will require more emphasis on energy and fluid replacement, whereas strength and power sports – such as bodybuilding, sprinting and wrestling – will require more emphasis on muscle gain and maintenance.

However, some products – such as recovery drinks – can be useful across the board. For the sake of convenience, we’ll divide these products into the following categories:

• Energy replacement (eg, carbohydrate drinks)

• Fluid replacement (eg, electrolyte drinks)

• Recovery (eg, combined protein/carbohydrate drinks)

• Protein and strength/muscle gain (eg, creatine and protein drinks)

• Fat burners

• Health and protection (eg, vitamin/mineral supplements, antioxidants)

It’s important to understand that many products span more than one of these categories. For example, many fluid-replacement drinks contain useful amounts of energy-replacing carbohydrate; while recovery drinks proper often combine protein and carbohydrate with electrolyte minerals and vitamins and minerals.

Energy replacement drinks

Energy replacement drinks aim to supply carbohydrate in a rapidly absorbable form, to help provide fuel for hard-working muscles during vigorous exercise. Most energy drinks contain a combination of quick-releasing simple sugars and slower-releasing longer-chain sugars, to provide a quick-acting, yet sustained increase in blood sugar, which in turn helps keep muscles fuelled. There’s a mountain of evidence to show that muscles can store only enough carbohydrate (or more specifically glycogen – a form of carbohydrate) to fuel around 1½ to 2 hours of high-intensity exercise; when muscle glycogen stores start to become depleted, there’s a sudden and often dramatic drop in performance.

Trying to replenish carbohydrate using conventional high-carbohydrate foods (eg, bread, pasta, potatoes, etc.) while on the move is almost impossible; not only does digestion slow down the rate at which the released carbohydrate comes ‘on tap’, most people also find it impossible to consume solid food during vigorous exercise without suffering from stomach cramps, abdominal bloating and so on. In contrast, energy drinks can be drunk on the move without causing abdominal distress, and can therefore help to prevent glycogen depletion during endurance training/events.

Recommended for: anybody who performs large volumes of training, particularly where workouts last 90 minutes or more – such as runners, cyclists, swimmers, triathletes, rowers, etc – and those who need to train for shorter periods, but more than once a day. However, if you train less than this, a decent high-carbohydrate diet will almost certainly provide all the energy you need.

Fluid replacement drinks

Fluid replacement drinks supply fluid to hard-working bodies. In addition to water, electrolyte minerals such as calcium, magnesium, sodium, potassium and chloride are provided. Not only do these help to maintain normal physiological processes overall, but have particular side benefits – for example, sodium also stimulates thirst and increases the physiological drive to drink; and studies have shown that small amounts of glucose increase the rate of fluid absorption from the small intestine into the body, especially where the rapid intake of fluid into the body is important, eg during exercise in hot conditions.

Recommended for: anybody who exercises vigorously for more than an hour in hot or humid conditions. Conversely, those who exercise at more moderate intensities in cooler conditions have little to gain, as do those whose exercise sessions last less than one hour. In these circumstances, fluid from plain water and minerals from foods in the diet will normally be more than sufficient.

Recovery drinks

Recovery drinks are taken immediately after training and supply carbohydrate for the synthesis of muscle glycogen, and amino acids (protein) to replace and rebuild muscle fibres broken down during training. Studies have shown that the two hours after training are a window of opportunity, during which your muscles behave like sponge, soaking up what they need to power you through your next workout and build new muscle. Recovery drinks aim to supply precisely the right combination and ratio of carbohydrates and proteins, at the right time and in a form that’s convenient to prepare, easy to drink and rapidly assimilated.

Recommended for: anybody who trains seriously – including aerobic power and strength athletes; those doing high volumes of training, where the need to continually replenish muscle glycogen and avoid excessive muscle tissue breakdown is crucial; and even recreational trainers, who may find it hard to get a really well-balanced meal down their neck immediately after training.

Strength- and muscle-building products

Strength and muscle-building products tend to fall into two sub-categories: protein-based drinks with added ‘anabolic’ (stimulatory) ingredients; and stand-alone products such as creatine, and the amino acid metabolite HMB.

Protein drinks supply large amounts of easily assimilated protein to help muscle tissue rebuild after and between training sessions. The theory is that normal balanced diets struggle to meet protein needs for those who train hard; however, a number of comprehensive scientific studies into protein nutrition have produced rather inconclusive results for the benefits of protein drinks, especially where the basic diet (and protein content) is already good.

Creatine is a different matter. Taking supplemental creatine has been shown unequivocally to increase the size of the creatine phosphate reservoir in the muscles. Creatine phosphate is a body compound that provides energy for short-duration exercise, such as weight training, so the potential of creatine supplements is obvious. Creatine phosphate also boosts the regeneration of ATP (the body’s universal energy-producing compound, ie, under both aerobic and anaerobic conditions), helping you to sustain high-energy bursts for longer and recover more rapidly between bursts. This in turn translates into better performance during intense exercise; and, because it enables greater training intensities, it also helps to produce an increased training response; eg, increased muscle growth after resistance training.

There are also a number of other ‘strength’ products out there that purport to help build muscle (eg, HMB, glutamine, AAKG and so on). However, the scientific evidence for the efficacy of many of these products is much less solid and (especially if you’re on a budget) you may be better to save your money.

Recommended for:

Protein – strength and power trainers who may struggle to maintain an adequate dietary protein intake (around 1.5-2g of protein per kilo of body weight per day). However, for many trainers, a recovery formulation (which also supplies carbohydrate) could be a beneficial option;
Creatine – anybody who trains seriously and incorporates intense stop/start activity in their training, eg sprinting, interval training, weight training/lifting and endurance athletes seeking a bit of extra ‘kick’ for the line. It can also benefit vegetarians, whose dietary creatine intake tends to be quite low.(Note: older athletes and people with kidney problems should consult their doctors before supplementing with creatine.)

Fat burners

Fat burners are tablets or capsules that aim to help your body utilise more fat for fuel, thereby assisting the process of fat loss as part of a weight management plan. However, the ingredients in these formulations can vary wildly: from nutrients with good supporting evidence for their efficacy, to those without, and even to substances that are banned from sport. Taking a fat-burning product without first having in place a properly structured exercise programme that includes plenty of aerobic exercise and resistance training, and a well-balanced eating plan, is therefore a complete waste of time! As an added hazard, some of these formulations contain high levels of stimulants such as caffeine, which can cause unwanted side effects with prolonged and continual use. Note: exercise can in itself regularly boost metabolic rate by up to 20%

Recommended for: occasional, judicious use to help lower body fat for a specific target – for example, in preparation for competition, or to help shed weight after a layoff. However, in most cases, manipulation of your diet and exercise regime will be a far safer and more effective strategy to lower body fat.

Health and protection products

Health and protection products include vitamin/mineral formulations and antioxidants. The purpose of these products is to keep the body healthy to withstand the rigours of training in both the short and longer-term. Vitamin and mineral supplements aim to top up nutrients that may be short in the diet. Research shows that even with ‘well balanced’ diets, many people in the West have borderline intakes of nutrients, such as zinc (involved in protein turnover and growth and immunity), iron (oxygen transport), magnesium (energy production via ATP synthesis) and omega-3 fatty acids (immunity, energy regulation and brain function) to name but a few. Recent research on dietary antioxidants has shown that not only do they help maintain health in the longer-term, but they may also help reduce exercise-induced muscle damage and post-exercise soreness, boost recovery and even enhance training performance.

Recommended for: anybody interested in maximising their overall health and enhancing potential performance gains in the longer term.

So there we have it. Hopefully, this information will help you find your way through the ‘sports nutrition maze’! Remember though, the core of good sports nutrition begins in your kitchen with the foods you eat, not at the pharmacy or sports shop!

Andrew Hamilton BSc Hons, MRSC ACSM is editor of Peak Performance newsletter, a member of the Royal Society of Chemistry and the American College of Sports Medicine, and a writer/consultant to the fitness industry, specialising in sport and performance nutrition