Microbiota is a set of microorganisms resident in gut ecosystem that reacts to psychological stressful stimuli,
and is involved in depressed or anxious status in both animals and human being. Interestingly, a series of studies have
shown the effects of physical exercise on gut microbiota dynamics, suggesting that gut microbiota regulation might act as
one mediator for the effects of exercise on the brain. Recent studies found that gut microbiota dynamics are also regulated
by metabolism changes, such as through physical exercise or diet change. Interestingly, physical exercise modulates
different population of gut bacteria in compared to food restriction or rich diet, and alleviates gut syndromes to toxin
intake. Gut microbiota could as well contribute to the beneficial effects of exercise on cognition and emotion, either
directly through serotonin signaling or indirectly by modulating metabolism and exercise performance.