Long-lasting endurance is accompanied by two types of exhaustion: circuital and centrifugal. Circuital exhaustion is the result of local changes developing in muscles , while centrifugal exhaustion is a result of changes in a centrifugal nervous system.
According to one of the theories on centrifugal exhaustion, a higher level of serotonin in brain causes decrease in mental abilities and physical capacity. The level of serotonin in human brain is growing when the level of tryptophan (its precursor) in blood is getting bigger.
During endurance exercises, the level of BCAA is getting lower causing its easier permeability to a brain that intensifies a serotonin synthesis (responsible for the exhaustion of a central nervous system).
But it has been proved that giving BCAA delays the occurance of centrifugal exhaustion (stabilization of indicator tryptophan BCAA changes by delaying the decrease of a serotonin level in a brain.
What is more, amino- acids supplementation increases fatty acid oxidation spiral (one of the substracts in endurance exercises) . In one research, the influence of BCAA supplementation on increase of physical effort and the level of fatty acid oxidation occurred during physical effort with glycogen shortage in muscles was estimated.
Examined people were randomly divided into two groups. One of them were provided with a BCAA supplementation(300 mg/kg body mass a day) and the second one was a controlled group (placebo).
First day the participants underwent endurance exercises up to the level of a total muscle glycogen depletion. Next day all the people underwent a next long-time endurance exercise up to the level of a total exhaustion, during which there were measured: The time of the exercise, respiratory quotinent (RER), glucose concentration, fatty acids and a lactate concentration in a blood.
Achieved results showed the people from BCAA supplementation group were more resistant to exhaustion. They were able to perform exercises longer and the moment of “total exhaustion” came later than among the people from a ‘placebo” group (on average 17% ). What’s more, in BCAA group , a lower value of RER indicators and higher concentration of glucose in blood were observed.
The scientists claimed BCAA supplementation increases exhaustion resistance and intensifies the level of fatty acids utilization during endurance exercises with depletion of depletion in muscles.
1. Gawroński W., Szyguła Z. „ABC Medycyny Sportowej”, Medicina Sportiva, Kraków 2002.
2. Gualano A.B., Bozza T., Lopes De Campos P., Roschel H., Dos Santos Costa A., Luiz Marquezi M., Benatti F., Herbert Lancha Junior A. Branched-chain amino acids supplementation enhances exercise capacity and lipid oxidation during endurance exercise after muscle glycogen depletion.