Low fitness may outweigh obesity as risk for heart disease

September 9, 2004 in Diabetes & Diabetes Prevention, Heart Health, Nutrition Topics in the News, Sports Nutrition and Exercise

Low fitness may outweigh obesity as risk for heart disease

Staying fit may be more important than staying trim for a woman's risk of heart disease - but the opposite appears true when it comes to diabetes, according to two studies released this week.

In one, researchers found that among 906 middle-aged and older U.S. women, those who were more physically fit were less likely than out-of-shape women to have narrowed heart arteries or to suffer a heart attack or stroke over four years.  However, neither body mass index (BMI) nor abdominal obesity were in and of themselves predictors of artery disease or its complications.

The second study, of close to 38,000 women, found that BMI was far more important than exercise levels in the risk of developing type 2 diabetes.

People have long been advised to exercise and keep their weight down in order to cut the risks of both heart disease and type 2 diabetes. And though the two new studies differ on the relative importance of fitness and "fatness," experts say the overall implication is straightforward: Get regular exercise.

Exercise is the "common denominator" in both sets of findings because it boosts fitness and promotes weight loss.

The editorial accompanying these findings in this week's Journal of the American Medical Association, discusses that it is not only possible to be "fat but fit," but that fitness can also counter the ill effects of excess weight. In one study, researchers found that obese adults who were at least moderately fit had about half the risk of dying from cardiovascular disease as their lean but out-of-shape peers.

The bottom line is that adults should strive to accumulate at least 30 minutes of moderate exercise on most, if not all, days of the week - through activities like brisk walking, biking, swimming, gardening and housework.

Details of the first study:

Researchers from the University of Florida College of Medicine in Gainesville followed 906 women who had chest pain or other signs of possible heart disease at the study's start.

Women who were deemed fit were less likely to show artery narrowing, and were at lower risk of having complications such as heart attack and stroke over the next four years. Out-of-shape women were 46 percent more likely than fit women to suffer a cardiovascular complication.

High BMI was linked to several diseases that pose a threat to the heart, including high blood pressure and diabetes, but was not in itself associated with coronary artery disease or its complications.

Details of the second study:

This study included 37,878 middle-aged and older women whose BMI and activity levels were recorded at the outset. While physical activity lowered the risk of diabetes somewhat, BMI was a much more important factor.

Compared with normal-weight women, those who were overweight had more than three times the risk of diabetes, while obese women had nine-times greater risk. The researchers speculate that exercise may not fully counter the effects of excessive body fat when it comes to diabetes. For one, it's thought that fat tissue may release substances that affect the metabolism of insulin - the blood-sugar-regulating hormone that is rendered ineffective in type 2 diabetes.

All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.