Supplement Use for Endurance Sports

The argument in favor of supplement use

By Matt Sheeks

So you’re looking into supplements to see if they can give you an edge in your next competition, but you want to make a wise decision. Certainly you have heard a lot of anecdotal evidence about sports supplements but you wonder about its validity. Coming from a running background, I understand these concerns. Runners simply don’t believe that anything can help them improve but harder training, and lots of it. They are a fairly simple breed. They make an exception that altitude training can help them, because this will have a direct effect on the oxygen carrying capability of their blood, and this is something they can understand. However, it is hard to understand how having more of something in your body like a mineral could immediately make you faster, but I contest that this in fact the case.

If you subscribe to Central Governor theory (see my “Training Pages” at, then this will be a lot more congruent with your philosophy of training than if you rely solely on the Aerobic/Anaerobic model. If one can accept central governor theory, then it makes sense that even if you have not improved your aerobic fitness via training, you can still see improvements through supplement use, because, simply put, your brain will allow the body to do more work. One of the basic tenants of central governor theory is that your brain controls at what intensity the body can perform at. It is generally believed that there is a cardiostat (which measures heart rate), thermostat (measuring body temperature), and glycostat (measuring blood glucose concentration) that the brain uses to determine what intensity it will allow a person to perform at. In addition to this there is of course the nervous system itself which contracts the muscles (and most likely can measure muscular fatigue and soreness) and I believe a host of other functions performed by the brain.

What I am getting at is this: Your brain knows how hard the body can go before it will do irreversible damage to itself. If you have less of minerals or other building blocks of energy at the cellular level, your brain will shut you down sooner; not meaning that it will bring you to a standstill, but it will limit the intensity of work you can do. Therefore, one would want to have an abundance of certain vitamins, minerals, and potentially other compounds in the body that are essential for cellular performance. This will have an effect both in training and racing applications.

My recommendations: Below is a list of supplements I have found useful in multisport training and racing. These are the first and most basic changes I would make to your supplement routine.

(1) Iron Supplementation

Iron deficiencies will probably have the largest effect on your endurance performance. For reasons that are unclear to most researchers (though multiple theories have been espoused), it is very easy for distance runners to be deficient in iron. Iron is necessary for hemoglobin to carry oxygen to the muscles, so if you don’t have enough, you’re screwed. A good ferrous-sulfate supplement should really help to keep your iron count high. I would also search out a multivitamin that contains iron, which most don’t. A normal blood concentration is measured as 10-200 ng/dl, but to be honest, if your score is anywhere under 30, it is a reason for concern. I recommend taking an iron supplement with vitamin C to enhance absorption, and you will want to avoid taking it with any calcium supplement because the two inhibit each other’s absorption.

(2) Cal-Mag-Zinc Supplement

Calcium-Magnesium-Zinc supplements are cheap and readily available. Usually promoted as a bone health supplement, it can also have a profound impact on endurance performance. Both Magnesium and Zinc Supplementation have been shown to have significant performance improvements, while calcium is a primary substance in muscular contraction, as well as a trace electrolyte. It has been found to have positive effects on body composition. Based on the effectiveness of Magnesium and Calcium as performance enhancers, you might as well look for magnesium and calcium in your sports drink (they are often included because both are trace electrolytes), but these only come in the higher-end sports drinks.

(3) Multi-Vitamin

Before looking at more obscure supplements, I would recommend staying up on your vitamin and mineral intake with a Multi-Vitamin for several reasons. First off, what do you think will have the greatest performance benefit, a non-essential supplement, or a vitamin or mineral that has been proven to be essential for life? Of course avoiding a vitamin or mineral deficiency will be of primary concern. Even if it’s not as sexy as taking a supplement with the name Phosphopseudocreatineisadol, it sure is effective. Also, with so many minerals having studies that prove a performance benefit, its hard to remember to ingest all of them within a day, so you might as well take one pill to cover all your bases.

(4) Beta-Alanine

Unfortunately for early adopters such as myself, the word is out on Beta-Alanine, and it is now receiving the attention it deserves. Beta-Alanine is an amino acid produced naturally by the body. Studies have showed serious benefits (over placebo) including 13.9% increase in workload required to reach ventilatory threshold, 12.6% power increase at neuromuscular fatigue threshold, and 2.5% increase in time to exhaustion. The best results have been with supplementation over a good length of time, say one month, at a dosage of 1000mg/day.

(5) Caffeine

The old standby, caffeine is believed to improve performance by sparing glycogen (increasing fat as a fuel source) and by improving the release of several central nervous system neurotransmitters such as dopamine, norandrelone, and adrenaline. Everyone knows it works; the studies on caffeine’s efficacy (especially over longer distances) is practically undisputed. The recommended optimum dose is 3mg to 6mg per gram of body weight, though I have been happier at the lower end of that spectrum. Caffeine is really only believed to improve performance in the short-term, such as in a race-day application only, although I would like to see more research on constant caffeine use, since that is what most of us practice anyways. Advice on timing your use of caffeine is also varied; ingestion in the region 1-2 hrs before beginning a workout will be optimum. Experiment with what works for you, but be careful! Caffeine is easy to over-do or mis-time.

So, there you have it! You might have noticed that I did not mention either Cordyceps or Rhodiola Rosea, which are found in the highly popular Optygen HP supplement. This article was written, knowing it would be reproduced by First Endurance (the makers of Optygen), and I feel that they have already provided better research on these two supplements than I ever could! Thanks FE!

For the readers in the house, a synthesis of my research is below. Most of the data is taken from or The Lore of Running by Tim Noakes.



Definition: Mineral and trace electrolyte

Function: “Magnesium is required for more than 300 biological reactions in the body, including those involved in the synthesis of fat, protein, and nucleic acids, neurological activity, muscular contraction and relaxation, cardiac activity and bone metabolism. Even more important for athletes is magnesium’s pivotal role in both anaerobic and aerobic energy production, particularly in the metabolism of adenosine triphosphate (ATP), the ‘energy currency’ of the body. The synthesis of ATP requires magnesium-dependent enzymes called ‘ATPases’. These enzymes have to work extremely hard; the average human can store no more than about 3oz of ATP, yet during strenuous exercise the rate of turnover of ATP is phenomenal, with as much as 15kgs of ATP per hour being continually broken down and reformed.” If someone is deficient in magnesium, muscular contraction and relaxation abilities will be impaired.

Research: Research indicates that even a small reduction in magnesium levels can drastically impair endurance athletic performance. Studies show that endurance athletes increased maximal oxygen uptake, work output, and lowered lactic acid levels when supplementing with magnesium.


Dosage: The U.S. RDA has recently been raised to 400mg/day for men and 300mg/day for women. Many believe 450-500mg/day would be more appropriate even for sedentary adults. Most pills contain 250mg. Pumpkin seeds, almonds, and sesame seeds are great natural sources.



Definition: Zinc is a mineral/trace metal.

Function: Zinc affects carbonic anyhydrase levels, “which plays a key role in facilitating the removal of carbon dioxide from energy producing cells. Any reduction in this enzyme could theoretically cause a ‘bottleneck’ in aerobic energy production in cells by allowing carbon dioxide to back up.”

Research: Athletes on a high-zinc diet were found to have higher peak oxygen uptake, carbon dioxide output, and respiratory exchange ratios than athletes on a low-zinc diet.


These findings provide an explanation for previous findings of decreased muscle strength and endurance in adolescents and adults with low-zinc status. And the researchers conclude that low-zinc diets cause a drop in carbonic anhydrase levels, leading to impaired peak aerobic power, aerobic efficiency and ventilatory efficiency.

Dosage: RDA of 15mg/day or higher.



Definition: Calcium is a mineral and trace electrolyte

Function: “Calcium is needed to switch muscles on and off – without it no muscular contraction would be possible – and is also vital to the release of neurotransmitter chemicals, such as serotonin, acetylcholine and norepinephrine. Calcium is also an important co-factor for blood clotting and activates numerous enzyme systems in the body.”

Research: Recent research suggests that calcium is important in controlling metabolism, and can affect body fat percentage and prevent weight gain. Lower body fat means less demand on working muscles, thus improving performance.

A study comparing weight loss in obese men found that those on a high calcium diet had significantly greater weight losses than those on a low calcium diet. Many other studies have confirmed that those on higher calcium diets have better body composition and lower body fat percentages. However, no significant studies have been performed using athletes.

Dosage: High calcium foods include cheddar cheese (720mg per 100g serving), milk(620mg per pint), sesame seeds(420mg per 100g serving, canned fish(550mg per 100g serving), and spinach(136mg per 100g serving). Hammer endurolytes contain 50 mg per capsule. RDA is 1000mg.




Definition: Beta-Alanine is an amino acid found naturally in the body.

Function: Beta-Alanine is believed to affect Carnosine levels, which buffers lactic acid which would delay muscular fatigue.

Research: Beta-Alanine is a relative newcomer to the supplement scene, so there is a limited amount of research.

“The most recent study to be published on beta-alanine appeared in November of last year. In it, US researchers examined the effects of 28 days of beta-alanine supplementation on the physical working capacity at neuromuscular fatigue threshold, ventilatory threshold (VT), VO2max and time to exhaustion (TTE) in 22 women(5).

Unlike the studies above however, this compared the effects of pure beta-alanine supplementation against placebo (ie there was no added creatine with the beta-alanine).

Before and after the supplementation period, participants performed a continuous, incremental cycle ergometer test to exhaustion during which the above parameters were measured. The results were as follows:

*Compared to placebo where there was no improvement, the beta-alanine group experienced a 13.9% increase in the workload required to reach ventilatory threshold;


*The beta-alanine subjects were able to increase their power output by 12.6% at neuromuscular fatigue threshold (no improvement with placebo);


*The beta-alanine subjects extended their time to exhaustion by 2.5%.”

Dosage: 2000mg per dose (either 1x or 2x/daily) is common. Beta-alanine is relatively cheap, approx $25 for 100 pills at 2000mg per pill. It is also available in Optygen HP.



Definition: Caffeine is a stimulant produced from coffee beans, tea leaves, and other sources.

Function: Caffeine is believed to improve performance by sparing glycogen (increasing fat as a fuel source) and by improving the release of several central nervous system neurotransmitters such as dopamine, norandrelone, adrenaline,

Research: “Caffeine can increase mental focus and endurance, especially if you abstain, then load up before an important session or race (eg 2-5mg per kg of bodyweight one hour beforehand). The research suggests that while caffeine may give a small advantage over shorter events (1-3%), it could enhance exercise to exhaustion by 10-20% or more (9). Evidence also suggests that the ‘caffeine causes dehydration’ myth is not true (10,11) and that caffeinated drinks can safely form a part of an athlete’s daily diet and pre-performance regime without negative impact.” (PP online)

A Canadian Study showed that caffeine increased performance in a ride to exhaustion test by 23%, with an intensity of 85% VO2 max. Another similar study showed individual improvements of 20 to 50% (Noakes).

Over fixed distances, caffeine has been shown to provide a 1.5% improvement in 1500m times and also similar results during interval tests.

Dosage: Between 3mg to 6mg of caffeine per kg of body weight. Matt’s empirical evidence says 1 to 2 cups of coffee is optimum (150-300mg of caffeine). Common knowledge states that the caffeine should be consumed 1 hour or so before competition. Sometimes I feel that 2-3 hours before competition is better.


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