Many studies show consistent findings that physical activity is related to reduced depression and that the results are similar across cultures. Studies about the amount of exercise suggest that both moderate and vigorous exercise can reduce conditions of depression, but no studies have investigated the effects of exercise in regard to the frequency or duration. In addition, both aerobic and resistance exercise can reduce the conditions of depression, but it is not clear whether improvement of cardiorespiratory fitness is necessary to reduce depression. As for the relation of exercise to anxiety disorders, only two studies present data on anxiety conditions. They still show an inverse relation between exercise and anxiety.

Generally, the current level of evidence about the effects of exercise on depression and anxiety is not enough to draw a clear picture about the relations of the dose of physical activity to depression and anxiety. However, this situation is caused by a lack of studies rather than a lack of evidence.