The number of nerve cells in the brain typically decreases with age, and the levels of the chemical substances involved in sending messages in the brain change. Although researchers aren’t sure about the exact mechanism, exercise is strongly associated with protection against age-related decline in cognitive function.
Regular physical activity also may help postpone the decline in your ability to think quickly and may help improve reaction time. Additionally, exercise may aid your ability to shift quickly between activities and plan and organize tasks. Some studies also suggest regular exercise may help reduce risk for Alzheimer’s disease. The effects of exercise on brain health are partly due to its ability to improve cardiovascular function and blood flow within the central nervous system.
Studies in animals have found that exercise increases the number of small blood vessels that supply blood and nourishment to the brain, in addition to increasing the number of connections between nerve cells. Even if you’re starting to show early signs of memory loss, exercise may still help.
One small study found that walking at a moderate intensity on a treadmill for 30-minute sessions four times a week actually increased the thickness of the outer layer of the brain. Participants with declining mental function at the start of the study showed the greatest growth in the brain regions that typically degrade quickly in Alzheimer's disease. Studies also suggest a single session of aerobic exercise may produce short-term improvements in memory, attention, and reaction time.
You don’t have to run marathons to reap brain benefits. While there is evidence that age-related changes in brain structure and cognition can be offset by increased exercise, a recent study found that long-term endurance exercise didn’t offer much advantage over a generally non-sedentary lifestyle. In addition to influencing cognitive ability, physical activity also can help you relax, lift your mood, and reduce stress and anxiety. And it’s never too late to start.
To learn more about how regular exercise can help you with more than weight and fitness, purchase a copy of Eat Well and Exercise from Tufts Health and Nutrition Letter.