The Medicine Cabinet: Ask the Harvard Experts
By Howard LeWine, M.D.
Q: I keep hearing that exercise helps with memory and other brain functions. What’s the connection? What types of exercise and how much do I need?
A: Exercise boosts your memory and thinking skills both directly and indirectly. It acts directly on the body by stimulating physiological changes such as reductions in insulin resistance and inflammation. Exercise also encourages production of growth factors — chemicals that affect the growth of new blood vessels in the brain, and even the abundance, survival and overall health of new brain cells.
It also acts directly on the brain itself. Many studies have suggested that the parts of the brain that control thinking and memory are larger in volume in people who exercise than in people who don’t.
Exercise can also boost memory and thinking indirectly by improving mood and sleep, and by reducing stress and anxiety. Problems in these areas frequently cause or contribute to cognitive impairment.
Is one exercise better than another in terms of brain health? We don’t know the answer to this question, because most of the research so far has looked at walking. But it’s very likely that other types of aerobic exercise that gets your heart pumping will yield similar benefits.
We also don’t know how much exercise is best for the brain. Aim for an initial goal of 150 minutes per week of moderate intensity exercise, such as brisk walking. More is likely better — perhaps working your way up to 45 to 60 minutes of dedicated exercise time most days of the week.
Based on the studies, the effects are not immediate. It takes about six months to see some of the cognitive benefits of regular exercise.
If aerobic exercise doesn’t suit you, consider tai chi. The slow focused movements require learning and memorizing new skills and movement patterns. Studies in older adults have shown tai chi can enhance executive function, which manages cognitive processes such as planning, working memory, attention, problem solving and verbal reasoning.
(Howard LeWine, M.D., is an internist at Brigham and Women’s Hospital in Boston and assistant professor of medicine at Harvard Medical School.)