Dopamine is a neurotransmitter -- a molecule that neurons release to communicate with each other -- that is synthesized from the amino acid tyrosine. By increasing the amount of dopamine in certain regions of the brain, exercise can exert a number of health benefits that can promote positive well-being and even counter negative mental states. Although much of the research is novel and must be confirmed with future studies, the potential of exercise in supporting mental health is promising.
Stress and Depression
Exercise is beneficial for alleviating depression, and this is thought to be due to the effect of physical activity on neurotransmitter synthesis. Dopamine may have a distinct role in fighting stress and in countering depression by acting on the limbic system, a part of the brain that is important in emotional response. An article published in "Neuro Endocrinology Letters" in 2010 found "a close connection to the brain's pleasure, reward and motivation circuits that are particularly bound to limbic structures and to endogenous dopamine, morphine, and nitric oxide signalling."
Addictions are thought to be due, in part, to the release of dopamine in the nucleus accumbens -- the "reward" center of the brain. Exercise can boost the levels of dopamine in the brain in these same addictive cycles. We all know people who are "addicted" to exercise. In this way, exercise can create new, positive, addiction pathways that could counter negative addictive behaviors. An article published in "Current Neuropharmacology" postulates that the release of dopamine in exercise can counter amphetamine addiction.
Some schools of thought consider obesity a form of food addiction. As with all addictive behaviors, the food consumption that results in obesity triggers the release of dopamine in the nucleus accumbens in response to food. Of course, exercise combats obesity by burning calories, but by increasing dopamine synthesis in the nucleus accumbens, it may also help to counter the mechanisms of food addiction. The potential of exercise to combat food allergies is discussed in a paper published in "The Journal of Experimental Biology" in 2011.
Parkinson's disease is a neurological condition characterized by muscle rigidity, a lack of voluntary movements and tremors. The condition is caused by degeneration of dopamine cells in a part of the brain called the basal ganglia. By promoting the synthesis of dopamine, exercise can help to counter some of the symptoms of Parkinson's disease. A paper published in the "Journal of Neuroscience" in 2007 found results in support of this theory using mouse models. Giselle Petzinger, the principle investigator of the study, told "Science Daily" that "surviving dopamine cells in our animal models -- made to simulate what Parkinson's patients suffer with -- subjected to intensive treadmill exercise appear to work harder."