Physical Activity, Exercise, and Depression
Egil W. Martinsen
The concept of depression is used to describe several psychological states, ranging from transient feelings of sadness and depressed mood, which most people experience during their lives, to mental disorders. This entry will focus on the latter and on how exercise and physical activity affects them. In modern classification systems, such as the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders , fourth edition ( DSM-IV ), depression is classified under the mood disorders. These contain 2 major subgroups. Bipolar disorder is rare and affects about 1% to 2% of the population during their lifetime. Periods of illness vary between manic or hypomanic periods, from elevated mood to depressive episodes. Bipolar disorder has a strong genetic component, and mood-stabilizing medication is important for the majority of patients. There is almost no research on exercise intervention in bipolar disorders. Most experts believe that the role of exercise in Major ...