Older women who got more exercise and less television time were the least likely to be diagnosed with depression, according to a US study of thousands of women — with physical activity having the biggest impact.According to findings published in the American Journal of Epidemiology, researchers found that women who reported exercising the most in recent years were about 20 per cent less likely to get depression than those who rarely exercised.On the other hand, the more hours they spent watching TV each week, the more their risk of depression crept up.\"Higher levels of physical activity were associated with lower depression risk,\" wrote study author Michel Lucas, from the Harvard School of Public Health in Boston.More time spent being active might boost self-esteem and women\'s sense of control, as well as the endorphins in their blood, although the study could not prove directly that watching too much television and avoiding exercise caused depression, she added.The report included close to 50,000 women who filled out surveys every couple of years as part of the US Nurses\' Health Study, and covered the years 1992 to 2006.Participants recorded the amount of time they spent watching TV each week in 1992, and also answered questions about how often they walked, biked, ran and swam between 1992 and 2000.On the same questionnaires, women reported any new diagnosis of clinical depression or medication taken to treat depression.