Exercise influences serotonin levels by increasing the availability of tryptophan, the precursor to serotonin, in the brain. This is mainly achieved through the release of certain neurotransmitters during physical activity, which subsequently leads to enhanced serotonin production. Higher serotonin levels are associated with improved mood, reduced symptoms of depression, and overall emotional well-being. Regular aerobic exercises, such as running or cycling, have been shown to have significant effects on serotonin pathways, further contributing to the mental health benefits of physical activity by promoting a sense of well-being and enhancing stress management.