Sports Supplements – Creatine For Endurance Athletes

Creatine supplements can boost your endurance training without encouraging weight gain

Swimming Endurance Athlete

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.

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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.

Bike Endurance AthleteCreatine 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).

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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).

Running Endurance AthletePrior 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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Sports Nutrition – Does sodium bicarbonate supplementation improve performance?

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

At a glance

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.

Drinking Sodium Bicarbonate

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.

Increasing Endurance

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.

Protein and lactate

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).

Protein and mitochondria

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.

Dietary sodium intake

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

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