Updated June 25, 2002

Obesity, Type 2 Diabetes, and Physical Activity
What's the Connection?

by Richard M. Weil, M.Ed., C.D.E.

Fit and fat

More and more evidence shows that moderate levels of physical activity have positive effects on cardiovascular disease, weight control, and diabetes. Virtually every study of cardiorespiratory fitness shows that the fittest people—those who can walk the longest on a treadmill—are healthier than unfit people, even if the fit person is overweight. In this case, "healthier" means having lower cholesterol, triglyceride, blood pressure, and blood sugar levels and living longer. Research also shows that people who follow the Surgeon General's guidelines for activity are twice as likely to stay active as are people who begin programs of formal exercise.

Many studies also show that the healthiest person is not always the thinnest, especially when the overweight person is physically fit. In one well-known study, researchers compared overweight or obese fit people (yes, you can be fit and fat) to normal-weight, unfit people. It turned out that the overweight, fit people were healthier and lived longer than the lean, unfit people. They had healthier cholesterol levels, triglycerides, blood pressure, and blood sugar levels. They also had less diabetes and were 2.3 times less likely to die prematurely.

So often the emphasis is on weight loss to get healthier, but here's evidence to show that even if you are overweight, you can be healthy, as long as you are fit. And in many of these studies, fitness was achieved by individuals who walked for activity at moderate paces of 3-3 1/2 miles per hour. In some cases they accumulated the 30 minutes throughout the day, while in other cases they did it all at once.

Getting moving now

Whether you choose to exercise vigorously or adopt the Surgeon General's lifestyle plan for physical activity, it is helpful to write down your plan and keep records of your progress. Your plan might include walking to the store for groceries, walking an extra stop before getting on the bus, or taking the stairs instead of the elevator. Any intentional change in your activity level, however small it may seem, will help you on your way toward more activity and better health. The most important thing is to get started.

Becoming more active is very safe for most people. However, if you are pregnant or if you are over 69 and are not used to being active, check with your doctor first. If you are neither pregnant nor over 69 but aren't sure if increased physical activity is safe for you, ask yourself the following questions:

• Has your doctor ever said that you have a heart condition and that you should only do physical activity recommended by a doctor?
• Do you feel pain in your chest when you do physical activity?
• In the past month, have you had chest pain at rest, when you were not doing physical activity?
• Do you ever lose your balance because of dizziness, or do you ever lose consciousness?
• Do you have a bone or joint problem that could be made worse by a change in your physical activity level?
• Are you currently taking prescription drugs either to control your blood pressure or for a heart condition?
• Do you know of any other reason why you should not do physical activity? For people with diabetes, having neuropathy in your feet may make certain activities inadvisable. If you have any foot problems, including numbness in your feet, consult your doctor before increasing the amount of activity you do (even walking!).

Richard Weil is an exercise physiologist and a consultant to the Naomi Berrie Diabetes Center at Columbia Presbyterian Medical Center in New York City.

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