Exercise: Not Just for Weight Loss

Think about all the conditions that regular exercise can ameliorate:

  • Diabetes
  • Hypertension
  • Metabolic Syndrome
  • Obesity
  • Osteoarthritis
  • Depression

Does the last one on the list surprise you? The medical field has known for years that regular exercise can help treat mild to moderate depression. But how exactly does exercise make an impact on depression? Well, researchers are making great strides in describing the physiology behind this phenomenon.


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In an article recently published in the New England Journal of Medicine, the author describes recent advances in basic science linking stress and depression. Stress hormones such as cortisol induce increased production of a molecule called kynurenine. Circulating kynurenine then crosses the blood brain barrier and is converted to metabolites that increase reactive oxygen species and inflammation and increase glutamate transmission. Neurotrophin production is also decreased. These changes are considered to play a role in major depression (see review article), in addition to deficiency in serotonin transmission.


However, when skeletal muscle is active, it converts kynurenine to a form that cannot cross the blood-brain-barrier. This is how exercise can promote our brain’s resilience to stress. The author concludes that exercise may be a key adjunct therapy in stress related disorders.