Philip J. Goscienski, M.D.
Back in the Stone Age you would have needed a good memory. All the knowledge that existed among humans was transmitted among and down through generations by the spoken word. If you were one of the fortunate ten percent or so who lived past the age of 60 that memory would have been a prized asset for the clan or tribe, passing on decades of experience that enhanced your group's survival.
An English research team found that persons who were physically active during their mid-30s had a slower decline in memory as they aged than did their couch-potato fellows. Observers in the United States also found that the fittest persons showed the least decline in their memory skills. The so-called gray matter of the brain, where thinking, movement, vision and other functions are located, shrinks as we age. The loss is least in those who exercise the most.
It doesn't take intense exercise to get results. Persons who walk 1 to 2 hours a day have a significantly slower decline in mental ability. There are fewer studies on bikers, hikers, swimmers or rowers but all exercise does at least some good. Those who spend several hours a week gardening or engaging in similar unorganized activity also retain more brain power.
When you exercise, your brain, which even at rest garners about 25 percent of the blood that your heart pumps out with every beat, has more to do. It directs muscles to work, sends and receives nerve impulses that maintain balance, reacts to dangers ahead and juggles energy reserves. Just like back in the Stone Age.
Cardiologists know that we need intermittent bouts of moderately intense physical activity in order to keep blood vessels in the heart supple and flexible, ready to carry more oxygen and nutrients in times of stress. The same mechanism benefits the brain too, probably for the same reason. Whether you were the hunter or the hunted back in the Stone Age, sharpened senses, quick thinking and the ability to suppress pain made the difference between having lunch and being lunch.
When I was in medical school the prevailing theory was that once the brain had matured it could never form new cells. We were all destined to inevitable senility starting at about the age of 25. That's not so. Exercise, by increasing blood flow, actually helps to release growth factors within the brain so that new cells and new connections between older cells continue to form.
Exercise also releases endorphins, chemicals that have some morphine-like properties and that provide runners with their so-called runner's high. Whether or not such a phenomenon exists, exercise does alter the way brain chemicals work, and it even increases the production of these neurotransmitters. Such alterations could affect how well brain cells survive over many years, perhaps inducing very small changes that accumulate over decades and resulting in preservation of memory skills.
If you want your brain to keep working as long as the rest of your body does, it's a good idea to exercise. There are no harmful side effects except for an occasional sprain, and the price is right.
Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at firstname.lastname@example.org.