Exercise: the bigger picture

Philip J. Goscienski, M.D.

December 2008

The typical news item or TV story about exercise almost always focuses on weight loss or avoiding heart disease but if you're not overweight (by much) or if you come from a heart-healthy family, why bother?

It helps to understand that nature has hard-wired our bodies for a lot more physical activity than the vast majority of Americans even think about. Without it, muscles waste away and bones become fragile.

When we work out (or simply work) it opens up blood vessels and keeps them supple. That lowers the risk of heart attack and stroke. As important as those diseases are, there's more to the story.

Our body burns more blood sugar (glucose) when we're active. Whatever glucose isn't used up immediately is converted into fat. During the Stone Age an intermittent accumulation of fat when times were good helped those ancient relatives of ours to survive when food was scarce. But now times are always good and we never have to use that stored energy. The obesity epidemic was inevitable.

Our diet contains much more saturated fat, which raises cholesterol levels, than that of Stone Age hunters. Being physically active helps to keep cholesterol in the normal range; total cholesterol and LDL (harmful cholesterol) stay low and HDL (good cholesterol) goes up.

Keeping blood vessels supple and free from cholesterol build-up prevents them from getting clogged. High blood sugar distorts growing blood vessels. Although most of us worry about Alzheimer's disease, about half of the dementia that we encounter in old age is the result of clogged and distorted blood vessels in the brain.

People who exercise have more energy and sharper wits than those who don't and it's not because bright, energetic people are more likely to exercise! Being active for a few hours a week helps to keep body fat from accumulating, which is not exactly rocket science. Neither is the obvious conclusion that if you're carrying around an extra 20 or 30 pounds of fat it's like carrying a heavy backpack wherever you go. However, it did take some scientific research to come with even more reasons to explain why non-exercisers complain of fatigue and fuzzy thinking.

Moderate physical activity lowers blood pressure. In adults as well as children, even mild elevations of blood pressure have a deleterious effect on thinking ability and memory.

When the blood glucose is even slightly above normal it has similar effects on the brain. Persistent elevations of glucose levels make it harder for insulin to allow glucose to enter muscle cells. That explains why chronic fatigue is one of the major early symptoms of diabetes.

Regular exercise helps to grow new brain cells, which should be great news to Baby Boomers who hope that their brain will last as long a the rest of their body does.

As long-distance runners and other hard-core athletes have known for years, exercise provides a sense of well-being, the effect of raised levels of "feel good" chemicals known as endorphins. These hormone-like substances probably kept Stone Agers from fretting about how tough life was back then.

Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at drphil@stoneagedoc.com.