Evidence continues to mount that even a little bit of exercise goes a long way toward preventing depression. A recent study in the American Journal of Psychiatry found that just 20 minutes a day reduces the risk of becoming depressed later in life by a third, regardless of lifestyle factors such as age, smoking and body mass index. Researchers compared people who took part in moderate aerobic exercise for a recommended two and a half hours each week to those who did not.
The National Health Service of the United Kingdom recommends that adults aged 19 and 64 should do at least 150 minutes of moderate aerobic exercise a week or 75 minutes of vigorous aerobic exercise every week. Adults should also strength train two or more days a week, according to NHS guidelines.
Examples of moderate exercise suggested by NHS would be brisk walking, water aerobics, riding a bike, doubles tennis, pushing a lawn mower, hiking, skateboarding, rollerblading, volleyball and basketball.
Vigorous exercise would be activities such as jogging or running, swimming fast, riding a bike fast or on hills, singles tennis, football, rugby, skipping rope, hockey, aerobics, gymnastics and martial arts.
“We found that higher levels of physical activity were protective from future depression in children, adults and older adults, across every continent and after taking into account other important factors such as body mass index, smoking and physical health conditions,” said Dr. Brendon Stubbs of King’s College London. He is head of Physiotherapy at the South London and Maudsley NHS Foundation Trust.
The recent work collected data from 49 unique studies in the United States, United Kingdom, Australia, Brazil, Belgium and Sweden of people who did not have a mental illness. The study followed almost 267,000 people during a seven-and-a-half-year period.
This new research comes on the heels of another recent study published earlier in the American Journal of Psychiatry that found one hour per week, even without becoming breathless or sweating, reduces risk of future depression. That research, known as the HUNT study, involved 33,908 adult Norwegian men and women. Their levels of exercise and symptoms of depression and anxiety were monitored over an 11-year period.
The findings of the HUNT study suggest that surprisingly small amounts of low-intensity physical activity can protect against future depression, regardless of age or gender.
Notably, the researchers found that people did not have work themselves into a state of breathless, sweaty, exhaustion to win psychological benefits from exercise. Low levels of aerobic intensity were just as effective as moderate-to-vigorous physical activity in protecting against future depression, according to the study’s authors.
Authors of the latest report say their research demonstrates the importance of public policy that promotes physical exercise.
“Given the multitude of other health benefits of physical activity, our data adds to the pressing calls to prioritize physical activity across the lifespan,” said Stubbs.
“The challenge ahead is ensuring that this overwhelming evidence is translated into meaningful policy change that creates environments and opportunities to help everyone, including vulnerable members of our society, engage in physical activity,” said Dr. Simon Rosenbaum. He is senior research fellow at the University of New South Wales Sydney and the Black Dog Institute.