Updated June 25, 2002

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

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

Together, insulin resistance and hyperinsulinemia are associated with a cluster of abnormalities collectively known as
syndrome X. Those abnormalities include high blood pressure, heart disease, high triglycerides, and decreased levels of HDL ("good") cholesterol. Syndrome X has been shown to indicate a predisposition to diabetes and heart disease. Treatment includes drugs to lower blood pressure and triglycerides and to control blood sugar. But even the powerful drugs that are now available cannot reverse diabetes or obesity or completely eliminate the health risks that come with these conditions. That's why it's important to add lifestyle measures, including increased physical activity, to the treatment regimen.

Physical activity

Research shows that regular physical activity can improve insulin sensitivity (or lower insulin resistance) by 20% to 30% by building muscle and reducing body fat. It also helps lower blood sugar (exercise has an insulinlike effect) and control weight. Research is also very clear that it is almost impossible to maintain weight loss unless an individual is physically active.

Physical activity increases muscle and bone strength, increases the efficiency of the heart and lungs, reduces cholesterol levels, reduces blood pressure, increases energy, improves quality of sleep, improves appearance and posture, and reduces the risk of falling. It also increases mental acuity, enhances psychological well-being, improves mood, and reduces the symptoms of anxiety and depression (one study showed it may prevent depression).

The current "official" recommendations regarding physical activity are for all Americans over age two to accumulate 30 minutes of moderate-intensity physical activity on most, preferably all, days of the week. These recommendations were released in 1996 in the Surgeon General's report, "Physical Activity and Health." They suggest a "lifestyle" approach to physical activity and health, and they complement earlier guidelines that called for formal exercise 3-5 times a week, for 15-60 minutes, at 60% to 85% of maximum heart rate. These goals, set by the American College of Sports Medicine in 1978, are still worth pursuing for higher levels of fitness, but it is possible to improve your health and maintain good health with less vigorous activity. The new guidelines provide options for people who are unwilling or unable to participate in more formal exercise.

Moderate-intensity activities use large muscle groups and are equivalent to brisk walking (3-3 1/2 mph), swimming, cycling, dancing, gardening, or doing yard work. (See "Less Vigorous, More Time; More Vigorous, Less Time" for more examples of moderate-intensity activities.) The full 30 minutes of activity need not be done all at once. Rather, it can be done in bouts of 10 minutes throughout the day and can be incorporated into the activities of your daily life. Here are some suggestions for being more active during the day.

• If you use public transportation, walk an extra few blocks to the next bus stop before you board. Get off the bus a few blocks early and walk to your destination.
• Take the stairs instead of the elevator.
• Park your car a little further than usual from the grocery store so you get a walk between car and store.
• Get up occasionally from your desk during the day to stretch and walk around. Try to fit in a walk during your lunch break.
• Cut your own grass with a push mower.
• Rake your own leaves.
• Wash your car by hand.
• Use a bike for errands or walk whenever possible.

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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