How Much Exercise is Enough?

Exercise Benefits

Study Links Daily Energy Spent to Specific Health Gains, Costs Saved

Researchers have known for several years that increasing physical activity can greatly increase the health of people with type 2 diabetes, by reducing the risk for heart disease and helping to prevent other diabetes-related complications. Now a study published in the June issue of Diabetes Care shows precisely how much exercise it takes to achieve specific gains in blood glucose, blood pressure, total cholesterol and triglyceride levels, along with the average annual medical costs that can be avoided.

Researchers from the Department of Internal Medicine at the University of Perugia, Italy, found that it took a minimum of walking about three miles per day for otherwise sedentary people with type 2 diabetes to see a significant improvement in health and medical-related expenses over a two-year period. In contrast, people who did nothing over that same time period saw a decline in health and a rise in medical expenses. An editorial accompanying the study encourages health care providers to make walking a priority for their patients with diabetes, and to provide them with counseling and support to ensure that they stick with a daily exercise program.

On average, those who increased aerobic activity by 38 minutes per day (walking about 2.2 miles or 4400 steps), even without losing any weight, reduced A1C levels by an average of 0.4 percent; total cholesterol by 10 mg/dl; triglycerides by 48 mg/dl systolic and diastolic blood pressure by 6 and 3 mmHg, respectively; CHD (coronary heart disease) risk by 2.6 percent; and annual medical costs by $288. All study participants also took part in an intermittent counseling program over the two-year study period.

The greatest improvements in health and medical costs accrued by increasing physical activity by roughly 83 minutes per day (walking about 5.3 miles or 10600 steps) over a period of two years. Expending this much additional energy lowered A1C levels by 1.1 percent; LDL (bad) cholesterol by 6 mg/dl; triglycerides by 57 mg/dl; blood pressure by 7 mmHg (systolic) and 5 mmHg (diastolic); CHD risk by 4.8 percent; annual medical costs by $1,248; and increased HDL (good) cholesterol by 10 mg/dl. In fact, after two years of daily exercise at this level, the number of people on insulin therapy fell by 25 percent among all subjects receiving physical activity counseling and there was an average reduction in insulin dosage of 11 units per day.

In contrast, sedentary people who did nothing to increase physical activity spent an additional $516 per year on medical expenses over a two-year period. They also significantly increased their use of diabetes medications, and saw a rise in blood pressure, cholesterol and triglyceride levels.

The accompanying editorial, written by James O. Hill, Ph.D., at the University of Colorado at Denver and Health Sciences Center, strongly encourages health care providers to get patients started on a daily exercise plan.

"Just remember that when it comes to physical activity, every little bit helps and even an extra 2000-2500 steps/day will bring measurable improvements in health for most of your patients," Hill wrote.

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Diabetes Care, published by the American Diabetes Association, is the leading peer-reviewed journal of clinical research into the nation