Dementia: Regular aerobic exercise improves brain function
A recent study by a team at the University of British Columbia has shown that regular aerobic exercise—any form of sustained physical exertion that significantly raises the heart rate—actually grows the hippocampus, a part of the brain that is crucial to short-term memory. By contrast, strength training (a mainly anaerobic exercise) or less strenuous activities (e.g., Pilates) do not appear to have the same brain-boosting effect.
This is a very encouraging discovery, particularly given the rapid rise in dementia worldwide. With a reported 9.9 million new diagnoses annually (one every three seconds), it is expected that 152 million people will suffer from with the debilitating condition by 2050.
How exercise helps the brain
Exercise benefits memory and cognition directly as well as indirectly. The direct benefits of exercise include reduced insulin resistance, which is positively correlated with inflammation, a known cause of dementia. Exercise also causes the brain to release certain chemicals, known as growth factors, which encourage not only new blood vessels to grow, but also the production and longevity of actual new brain cells.
The indirect benefits of exercise derive principally from its abilities to improve mood, relieve stress, and promote sleep, all of which lower inflammation and have been linked to better cognition.
Meanwhile, other studies have found that people who exercise tend to have a bigger prefrontal cortex and medial temporal cortex. The prefrontal cortex plays key roles cognition, personality expression, and decision making. The medial temporal lobe includes the hippocampus, and it is crucial to declarative memory—that is, the ability to recall personal events and factual information. What is “even more exciting,” says Dr. Scott McGinnis, an assistant professor of neurology at Harvard Medical School, is that we now have evidence that such results can be produced by “engaging in a program of regular exercise of moderate intensity over six months or a year.”
Everyone can reap the rewards
The simple lesson that everyone should take from these findings is: get exercising, in whichever way you enjoy the most! Almost all of the studies so far, including the most recent one, have sampled walkers. Therefore, says Dr. McGinnis, “it’s likely that other forms of aerobic exercise might yield similar benefits.”
What’s more, you don’t have to pound the pavement endlessly to build your brain. The University of British Columbia team instructed study participants to walk briskly just twice a week for one hour at a time—a total of just 120 minutes per week. For general health, the standard advice is to exercise at a moderate intensity for 30 minutes at least five days per week, adding up to a total of 150 minutes. But the most important thing is to simply get moving: start with a few minutes each day, if that is all you can manage, and slowly increase the duration as you start to feel fitter. And remember, every minute counts—try parking your car a little farther away from work, for example.
Other great aerobic exercises include swimming, dancing, stair-climbing, tennis, and squash. You can even lift your heart rate at home while doing chores such as leave-raking. As a rule of thumb, anything that induces a light sweat indicates that you’re working hard enough.
Not everyone likes to exercise by themselves, so joining a local class, finding a “gym-buddy”, or hiring a personal trainer can be great sources of motivation, not least because they hold you accountable to someone else. Another way to stay motivated is to set a fitness goal and keep a record of your progress toward it.
Ultimately, however you choose to exercise, the aim should be for it to become a habit, something you take for granted as part of your routine. For as more and more studies show, exercise really is one of the best medicines available, for both body and mind. What better reason to break a sweat?