• Welcome to Phoenix Rising!

    Created in 2008, Phoenix Rising is the largest and oldest forum dedicated to furthering the understanding of and finding treatments for complex chronic illnesses such as chronic fatigue syndrome (ME/CFS), fibromyalgia (FM), long COVID, postural orthostatic tachycardia syndrome (POTS), mast cell activation syndrome (MCAS), and allied diseases.

    To become a member, simply click the Register button at the top right.

Bodybuilder Doctors take on "central fatigue" aka PEM

drob31

Senior Member
Messages
1,487
I thought this was an interesting take from a different pespective:

Central Fatigue
i2.gif


In addition to focusing on the causes of muscle fatigue, recent research has also centered on mental fatigue during exercise. This is commonly called central fatigue because it results from impaired function of the central nervous system. Although central fatigue does not affect your muscles directly, it can reduce your capacity to perform.

The basis behind the central fatigue hypothesis is the theorized correlation between levels of the amino acid tryptophan in the brain, which is a precursor for the neurotransmitter serotonin, and the degree of mental fatigue.

When tryptophan enters the brain, it leads to increases in serotonin levels, which can depress the central nervous system, causing sleepiness and fatigue.

One of the ways that has been suggested for fighting off the increases in tryptophan entering the CNS is the use of branched chain amino acids (BCAA) during exercise. Most of the blood tryptophan in the body is loosely bound to albumin, one of the blood proteins, with a certain amount free.

The free tryptophan is transported, along with other amino acids (such as the branched chain amino acids leucine, isoleucine and valine) into the CNS. Thus tryptophan levels in the brain, and subsequently serotonin levels, increase when there is an increased ratio of free tryptophan to the total BCAA concentration.

The more BCAA present the less tryptophan enters the brain and less serotonin is produced. The end result is less central fatigue. The process is much more complicated than what I've just described and there are many other players that can influence brain serotonin levels.

Also there is still some controversy about whether the central fatigue hypothesis is even valid. Nevertheless, there are now intriguing theories and some evidence to support a possible role of nutrition in central fatigue during rest and exercise.9

http://www.bodybuilding.com/fun/md32.htm