Running on insulin – how exercise affects diabetes
When doctors warned Paula Harper not to run a marathon back in the late ’70s because she had diabetes, the nurse and mother of three from Phoenix chose to ignore them.
“I noticed right away that the more activity I did, the less insulin I needed,” says Harper, who has Type I diabetes. She went on to complete 31 marathons, a 50-mile ultramarathon, five triathlons, and six 100-mile-plus bicycle races. She raced wearing a T-shirt that proclaimed “I run on insulin” and had so many people approach her to talk about diabetes and exercise that in 1985, she founded the International Diabetic Athletes Association.
“In retrospect, what I did seems scary,” admits Harper, who says doctors were concerned that a long-distance event would deplete her blood-sugar stores. However, today’s blood-glucose self-monitors make it much easier to avoid the low-blood-sugar reactions that can be dangerous for anyone with diabetes, she says. “But I knew that running made me feel better and helped me cope with my diabetes.”
Today, people with diabetes participate in virtually every sport–from scuba diving to skydiving–at all levels of competition. And over the past decade, physicians have increasingly recommended exercise as one of the most effective ways to help people with diabetes lead normal lives and reduce their risk of serious complications.
In recent years, studies have shown that physical activity helps prevent the most common form, Type II or non-insulin-dependent diabetes. Both age and obesity put people at risk for Type II diabetes, which in our aging and overweight society is increasing at an alarming rate.
“Diabetes is the most rapidly growing chronic disease in the country,” says physician David Nathan, director of the Diabetes Research Center at Massachusetts General Hospital in Boston. Now affecting 7 percent of American adults, diabetes is expected to affect 10 percent by the year 2000, says Dr. Nathan, and up to 15 to 20 percent of older and minority adults. “Along with diet,” he says, “exercise is the most cost-effective therapy we have for to prevent diabetes.”
Exercise helps people with diabetes because it affects the very thing they need to control, their blood-glucose level, notes exercise physiologist W. Guyton Homsby, Jr., assistant professor in the department of medicine at West Virginia University. “Diabetes is a disturbance of the metabolism that causes blood glucose to be too high,” says Homsby, who has Type I diabetes and competes in track-and-field events and also lifts weights. “Exercise can take glucose out of the blood to use for energy during and after exercise, which lowers blood-glucose levels.”
Exercise also helps people lose weight and conditions the body to use the hormone insulin more efficiently. This means people with Type I diabetes, whose bodies don’t produce insulin, typically require a lower dose of insulin when they exercise.
And some with Type II diabetes, who take oral drugs to manage their condition, often find that after they begin exercising regularly, they no longer may need diabetes medication. “It’s a delicate balancing act, and each individual reacts differently,” notes Homsby, who served as editor in chief of the American Diabetes Association’s new Fitness Book for People With Diabetes.
Before starting an exercise program, people with diabetes should consult a physician. This is particularly important because diabetes raises the risk of cardiovascular disease, and people with complications affecting the eyes and feet may need expert guidance in establishing a safe regimen.
“Being consistent with exercise is extremely important for people with diabetes,” says Chris Silkwood, program director for the Houston-based Diabetes Treatment Centers of America. Diagnosed with Type I diabetes 14 years ago, Silkwood says she was “misdiagnosed for quite some time, but what saved me was that I’m a regular exerciser who eats a healthy diet. With diabetes, the way you choose to live your life will greatly determine the course of the disease.”
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