Gatorade for your nervous system

At Sparta, we just switched our supplement provisions to focus more on amino acids before, during, and after workouts. The first couple of weeks, athletes have asked us how much caffeine was in this new supplement. When the answer was none, they asked what other stimulant was included because they felt more alert. Again, the answer was none. Amino acids are the building blocks for protein, like sugar or glucose is to carbohydrates, so what could amino acids possibly do to cause this heightened arousal?

Luckily, this issue of amino acids and their role in fatigue has been studied by experts such as Eva Blomstrand, a scientist out of the Karolinska Institute, Stockholm, Sweden. In one of her 2006 studies, she discusses the central fatigue hypothesis. Central fatigue is a more specific term for nervous system fatigue (see SpartaPoint 10/8/09), and it can be defined as exhaustion caused by increased secretion of serotonin, which removes the desire to exercise. During sustained exercise, amino acids, particularly Branched Chain Amino Acids (BCAAs, see SpartaPoint 8/18/10), are taken up by the muscle and their concentration in the blood subsequently decreases. However, another amino acid in the blood, tryptophan, competes with BCAAs, so tryptophan concentration subsequently rises, which causes its uptake by the muscle and brain. The final step in the hypothesis is that the increased levels of tryptophan in the brain cause a rise in serotonin, which ultimately results in fatigue.

ExerciseBCAA uptake (by muscle)Tryptophan (by muscle/brain) Serotonin (in brain)Fatigue

Though these mechanisms are not entirely clear and agreed upon, the key part of this central fatigue hypothesis is that supplementing your exercise program with BCAAs can decrease tryptophan’s transport into the brain, thus reducing serotonin’s concentration and resultant fatigue.

We use Cytosport’s Monster Amino product, because it provides a high level of BCAAs in a ratio similar to that found in muscle, and the taste allows our athletes to casually drink the solution before and during exercise. The key is to find the correct ratio and amount that suits your sport, gender, and bodyweight.

Just think of these amino acids as your Gatorade version of protein, quick replenishment of nutrients to avoid fatigue — nervous system fatigue.