We all know exercise is good for the body, and many of us are well-aware that exercise can make you feel better emotionally as well. But in his recent book, Spark: The Revolutionary Science of Exercise and the Brain (now available in paperback), John Ratey, MD, and Eric Hagerman take you inside your brain to learn just why exercise is so good for your mind. If the thought of making your heart more efficient and your physique a little sleeker isn’t enough to motivate you to exercise, maybe the incentive of keeping your mind razor-sharp will provide that extra nudge.
The authors make the case that, “The same things that kill the body, kill the brain.” Diminished blood flow to cells equals a slow death, they suggest. In the brain, a cascade of events involving decreased production of neurotransmitters that mediate communication between nerve cells leads to reduced blood flow to cells, which causes build-up of waste products, and leads to cell death. Pretty soon more cells are dying than are being born. And yes, contrary to the old notion that you’re born with all the brain cells you’ll ever have, scientists now know that new brain cells are born all the time. As Ratey and Hagerman write, “If your brain isn’t actively growing, then it is dying.”
Just as strengthening your muscles involves subjecting muscle cells to a new level of stress, brain cells also need to be forced to cope with a little stress to maintain their vigor. As we age, cells get progressively less able to withstand the stresses of life — they get a little more frail with each passing year.
“Exercise is one of the few ways to counter the process of aging because it slows down the natural decline of the stress threshold,” Ratey and Hagerman write.
The book cites many studies, among them one that showed an actual increase in brain volume in key thinking-lobes of the brain in a group of three-times-a-week exercisers as compared to their couch-potato cohorts after six months. The brains of the exercisers appeared two to three years younger than their actual age in brain scans.
So how do you exercise to train your brain? With your doctor’s approval, the authors recommend doing some form of aerobic activity — they suggest walking, jogging and running — six days a week for 45 to 60 minutes. Get a heart-rate monitor and exercise four days a week in the moderate zone, about 65 to 75 percent of your maximum heart rate, for about 60 minutes. For the other two days a week, your workouts can be a little shorter — clocking in at 45 minutes — but at a higher intensity: 75 to 90 percent of your maximum heart rate. You can add some resistance or weight-training exercise to round out your session.