Just 20 minutes a week of physical activity can make a difference in your mood. No one seems able to agree on how much exercise, or what type, is best for mental health. But a Scottish study, reported in the British Journal of Sports Medicine, has found that just 20 minutes of any physical activity, including housework, in a week is enough to boost mental health.
Almost 20,000 men and women participated in the study, which involved taking a quiz for the Scottish Health Survey about their state of mind and how much weekly physical activity they engaged in. Using a standard scale to measure distress levels, over 3,000 participants were classified as suffering from distress and anxiety.
After controlling for factors such as age, gender, and long-term health conditions, the findings revealed that any form of daily physical activity was associated with a lower risk of distress and anxiety. The range of activities that proved helpful included housework, gardening, walking, and sports. The most powerful impact was derived from sports, which lowered the risk of distress and anxiety by 33%. Not surprisingly, the results showed that the more activity a person engaged in, the lower their chances of psychological distress.
Physical activity reduces the risk of heart disease, certain cancers, and many other serious diseases. It also improves several biological risk factors for disease, such as glucose intolerance and inflammation. These factors themselves have been linked to depression and dementia. That explains the benefits of exercise in the long term, but why does moving the body help the brain in the short term, sometimes even immediately? There are several proposed mechanisms:
- Exercise tends to stimulate brain chemicals that foster the growth of nerve cells.
- Exercise affects neurotransmitters such as serotonin, which are known to influence mood.
- Recent studies suggest that a stress-reducing hormone produced in heart muscle, known as ANP, plays a role; as the heart works harder during exercise, the body produces more ANP, which helps control the brain's response to stress and anxiety.
