7 Lack of physical activity
Studies have found that low physical activity is related to depression. There are several mechanisms by which physical activity may influence risk for depression. Physical activity may serve as a distraction to negative affect which reduces risk for other maladaptive coping strategies (e.g., rumination), thereby reducing risk for depression. Exercise increases levels of self esteem. Physical activity exerts a neurobiological effect that may increase some neurotransmitters such as serotonin, norepinephrine and dopamine leading to increased positive affect and hence reduced risk for depression.
Although it is possible that physical activity reduces the risk for future episodes of depression, there is also likely to be circular relationship between exercise and depression. A principle feature of depression is anhedonia, which may cause individuals to discontinue physical activities they used to find enjoyable thus reducing protective factors and increasing vulnerability.