Intense aerobic exercise increases tryptophan availability in the brain, promoting serotonin synthesis for mood and cognition.

“the first has to do with a precursor for a neurotoxic substance called kine yearning which is formed from the amino acid tryptophan some of you may be familiar with tryptophan because of its important role as a precursor for other bioactive compounds including serotonin a neurotransmitter that's important for mood and cognition exercise actually increases the availability of tryptophan to be transported into the brain which is a good thing because in the brain it forms serotonin”