How Exercise Alters Brain Chemistry

A key component of your healthy lifestyle, exercise strengthens the heart, lungs and bones and helps you maintain a healthy weight. According to the Harvard School of Public Health, regular exercise -- defined as 2.5 hours a week of moderate intensity aerobic activity or 1.25 hours a week of vigorous activity spread over a few days -- also helps prevent Type 2 diabetes and keeps cholesterol levels under control. Scientists have found that exercise changes brain chemistry as well.

Brain Growth

• Exercise activates molecules in the brain that promote brain cell growth and repair, according to a 2007 study published in the journal "Current Medicinal Chemistry." One of the molecules, known as neural growth factor, or NGF, stabilizes the flow of chemicals to and from nerve cells and may protect those cells from the damaging effects of elevated blood sugar levels and over-activation. NGF also prevents age-associated memory loss and, together with another exercise-activated molecule known as brain-derived neurotrophic factor, promotes long-term learning and memory.

Anti-Anxiety

• Brain-changing effects of exercise may alleviate some symptoms of anxiety. Noting the limitations of current drug therapies for anxiety disorders, authors of a review that appeared in the August 2012 issue of "Expert Review of Neurotherapeutics" found consistent benefits of exercise for both nonclinical and clinical forms of anxiety. They recommended further studies to define more clearly the effects of exercise on the brain and determine which patients may benefit the most. A review published in the March 2013 issue of "Diabetologia" highlighted that exercise significantly improves symptoms of anxiety in patients with Type 2 diabetes; however, several studies of Type 2 diabetics with depression found mixed results or no benefits of exercise.

Antidepression

• Exercise exerts effects on the brain that are similar to those of the antidepressant drug fluoxetine, according to an animal study published in the April 2012 issue of the journal "PLoS One." Both drug therapy and daily voluntary exercise produced similar improvements in behavior that reflected decreased depression. In addition, both treatments resulted in similar increases in activity in an area of the brain that controls learning and memory, which are often diminished in people with depression, according to the University of Memphis Department of Psychology. Both forms of therapy also promoted nerve growth and increased the number of connections between nerve cells, helping prevent the brain atrophy and shrinkage that can result from depression.

Antioxidant and Anti-Aging

• A review published in the March 2013 "Scandinavian Journal of Medicine and Science in Sports" found that moderate aerobic exercise provides antioxidant benefits that protect brain cells from the damaging effects of accumulated toxins and waste products. However, researchers noted that anaerobic, high-intensity or exhaustive exercise may have the opposite effect and instead promote oxidative stress. Moderate exercise protected against oxidative stress and preserved the function of the energy-producing parts of brain cells in elderly mice, according to a 2012 study published in "Neurobiology and Aging."