Exercise can help you improve just about every aspect of your health, from boosting your cardiovascular fitness to lowering your risk of certain cancers. And now we know that it can also help improve your memory. Studies have found that people who exercise frequently have a distinctive brain-wave pattern, characterized by steep peaks and valleys, that is associated with alertness. These high-exercise folks are better at blocking out distractions and focusing, which means that they are better at paying attention to material that they want to remember and better at retrieving those memories when needed.
Research has also found that aerobic exercise can help maintain short-term general and verbal memory. This type of memory is especially important when you want to recall names, directions, and telephone numbers or match a name with a face.
The results of research reported in March of 2007 suggest an even more impressive role for exercise: building new cells in a specific region of the brain that is associated with the age-related decline in memory that normally begins sometime around age 30. The region is called the dentate gyrus, and it is part of the hippocampus, which itself is essential to memory. First, studies of mice showed that exercise could spark the growth of new brain cells in the mouse-equivalent of the dentate gyrus. Scientists noted that the growth of the new brain cells was reflected in an increase in cerebral blood supply. In a later study of 11 healthy adult humans who participated in a three-month aerobic-exercise program, a similar increase in the cerebral blood supply was noted, suggesting that exercise had caused the growth of new brain cells in the dentate gyrus of each of the human exercisers. Since the typical, gradual memory decline in humans that begins sometime around the thirtieth birthday appears to be associated with the dentate gyrus, the ability to spark the growth of new brain cells in this region of the hippocampus through exercise may mean that physical activity can help prevent or delay some of the decrease in memory function that naturally occurs as humans age.
Aerobic exercise also helps keep your heart strong and your blood vessels healthy and flexible, which helps ensure that your brain will continue to get plenty of oxygen and nutrients for optimum performance. This is important because, while brain cells make up only two percent of your body weight, they use a quarter of all the sugar and oxygen your body absorbs. Research also suggests that exercise boosts a chemical called brain-derived neurotropic factor (BDNF) that encourages the growth of nerve cells in the brain, makes their connections stronger, and helps shield them from harm.
Scientific research has not yet identified a specific type of exercise regimen or a specific amount of exercise that is most beneficial for memory and brain function. But it's worthwhile to note that the recent studies that showed brain-preserving boosts in BDNF involved older folks who started out walking briskly for 15 minutes and gradually worked up to 45-minute walks three days a week. And studies by the Centers for Disease Control and Prevention indicate that getting 30 minutes or more of moderate exercise on most days can help you capture many of the health benefits of exercise. So for now, a similarly moderate level of activity is probably a good goal to aim for. If you have been relatively inactive of late, however, you should check with your doctor before beginning an exercise plan.
On the next page, learn about how sleep affects memory.