Researchers have found that those who exercise 2.5 to 7.5 hours per week have better mental health than average. However, more than that is associated with poorer mental health.
For the study, researchers analyzed data reported by over 7,600 adults who took part in a U.S. national survey and compared the participants’ mental health to quantity of exercise.
The researchers say that it is the first study to show an association between too much exercise and poor mental health.
“The largest mental health differences occurred with two to four hours of exercise per week,” wrote Yeon Soo Kim, M.D., and colleagues at Teachers College, Columbia University.
“Beyond four hours, the trend begins to reverse. About 65 percent of those with poorer mental health exercised more than four hours per week, compared to 55 percent of adults in better mental health.”
The researchers were surprised to discover that when 7.5 hours of exercise were exceeded each week, symptoms of depression and anxiety rose significantly. This was the case in both men and women, and in people of all ages and different levels of health.
However, further research is needed to determine whether people who are more prone toward depression or anxiety are simply more likely to engage in extensive physical activity as a way to keep their mental symptoms under control, or whether larger amounts of exercise may actually cause symptoms of depression and anxiety.
The researchers also add that their findings support “the notion that regular activity may lead to prevention of mental health disorders.”
“If physical activity can prevent mental health disorders or improve overall mental health, the public health impact of promoting physical activity could be enormous,” the researchers said in the study.
Although the study found an association between large amounts of exercise and worse mental health, it did not prove a cause-and-effect relationship.
The study is published in the journal Preventive Medicine.
Source: Preventative Medicine