Does Exercise Increase Serotonin?

It has been well established that exercise is good for your self-esteem, especially when associated with rewards, such as feelings of accomplishment and social acceptance. However, in order to determine the underlying causes of these positive feelings, researchers have turned their attention to serotonin -- our so-called feel-good chemical -- and the link it shares with physical activity.

Identification

The neurotransmitter serotonin -- 5-hydroxytryptamine, or 5-HT -- is synthesized from the amino acid L-tryptophan in brain neurons. Serotonin is found mainly in large constricted blood vessels, the intestinal wall and the central nervous system. It facilitates a number of functions, including behavior, memory, appetite, mood, sleep, temperature regulation, libido, cardiovascular function, endocrine regulation and muscle contraction.

Significance

Apart from the assistance it provides for general bodily functions, one of serotonin's main properties that is of great interest to doctors is the effect it has on feelings of happiness and well-being. This is particularly relevant in the association between depression and low levels of serotonin, which is why researchers have long been attempting to discover ways to increase serotonin levels in the brain. According to Michael J. Norden, M.D, author of "Beyond Prozac," there are ways to increase serotonin synthesis without the use of drugs, one of which is exercise. So if you're wondering why your training sessions often leave you feeling elated and "on top of the world," this may very well be the reason why.

The Facts

Research suggest that positive internal dialogue, exposure to bright light and a healthy diet may all contribute to increased levels of serotonin. However, exercise and improved fitness seem to yield the strongest benefit. According to a study published in the "British Journal of Pharmacology," which sought to measure the effect of running on brain activity in rats, the evidence indicates that exercise increases tryptophan and serotonin. Other studies have verified raised levels of tryptophan following exercise.

Considerations

Although numerous studies have indicated that exercise may have a positive effect on serotonin levels in the brain, almost all of them have been conducted using animals. Therefore, results are not conclusive in terms of suggesting that this effect may be applicable to humans, which is why further research is underway. Nonetheless, whether serotonin levels in humans increase during exercise, the fact remains that exercise improves overall health and feelings of well-being.

Warning

In the case of severe depression, it is not recommended that you rely solely on exercise as a form of self-treatment. While exercise may be beneficial, not only for your mood but also your general health, the best approach is to seek help from a qualified psychiatrist.