It's yet another example that environment beats genes, say researchers from Massachusetts General Hospital. Just 35 minutes of any type of exercise—high-intensity, such as aerobic or dance, or low-intensity, such as yoga and stretching—every day reduces the risk of depression, or a further depressive episode, even in people with a genetic predisposition for the problem.
After searching a database of health information of around 8,000 people, the researchers discovered that those with a genetic risk were more likely to suffer depression over the following two years—unless they also exercised for around two hours a week.
The risk reduces further the more that people exercise; each additional four hours of physical activity a week sees a 17 percent reduction in the risk of a new depressive episode.
Although depression is the leading cause of disability around the world, medicine has few, if any, longterm answers to the problem.
The researchers suspect that exercise will be just one of a range of options for countering depression, and their research is continuing into other approaches.