People who walk briskly(迅速地) for two and a half hours a week have a 25 percent lower risk of depression, according to a study. Researchers from Cambridge University found that physical activity in line with government guidelines was also linked to better mental health. Their paper, published in JAMA Psychiatry, found that even those who managed half the recommended amount had an 18 percent lower risk of depression than those who did nothing.
Dr Matt Pearce, first author on the paper, said, "The key message of the paper is that risk of depression is substantially lower for individuals who are physically active, and that most of these lower benefits occur at levels below the current health recommendations. Physical activity should therefore be encouraged to improve mental health even in inactive individuals who struggle to reach current recommendations. "
The research combined data from 15 earlier studies, with 191, 130 participants, all looking at the relationship between depression and physical activity. Since the study was observational in nature, it cannot prove a cause-and-effect relationship.
The researchers found" only minor additional benefits" to mental health when people were physically active beyond the recommended levels. Professor James Woodcock, a senior author on the paper, said, "There are two key features of this relationship: firstly, that the biggest difference in the risk of depression was seen when comparing those reporting no activity with those reporting a small amount". "Even ten minutes a day appears to make a big difference. Secondly, that there appear to be minimal additional benefits of doing high volumes of activity."
The researchers said there were likely to be multiple reasons for their findings, including exercise activating certain networks in the brain and body, releasing feelgood hormones called endorphins(内啡肽). Besides, people who are physically active usually sleep better, a key component of protecting your mental health. It might also be that improvements to individuals' body image from being more active, and increases in social interaction during activity played a role. Getting out in green spaces was another likely factor to boost mood, with many studies linking the use of green spaces and lower depression risks.
