An estimated 65% of adults in the United States are either overweight or obese, and their excess weight translates to an increased risk of coronary heart disease. To determine if you are overweight, you can calculate your body mass index (BMI), a measurement of your weight in relation to your height. Or you can measure your waist circumference.
The adverse effects of obesity depend not only on the total amount of body fat you have but also on how that fat is distributed in your body. Excess weight concentrated in your abdomen is particularly dangerous because it leads to a condition called insulin resistance -- a reduced ability of the body to respond to insulin, a hormone secreted by the pancreas that helps the body use glucose, or sugar, as a source of energy. People with insulin resistance tend to also have high triglyceride levels, low levels of HDL cholesterol, high blood pressure, and thus an increased coronary heart disease risk. In addition, people with insulin resistance are more likely to develop diabetes, another risk factor for coronary heart disease.
Now new two new studies support the observation that people who carry their weight around their middle may face greater heart risks. The studies were reported in the Journal of the American College of Cardiology (Volume 50, page 752) and the Archives of Internal Medicine (Volume 167, page 1518).
The good news is that exercise may trim both your waistline and your odds of having a heart attack. In one study of more than 2,700 middle-aged adults, the larger that participants' waistlines were in relation to their hips, the greater their risk of plaque buildup in the arteries. In fact, waist-to-hip ratio was a better predictor of clogged arteries than was BMI.
The second study included 169 middle-aged men. In men of the same BMI, those with the lowest cardiovascular fitness had twice as much abdominal fat as their fit counterparts. And that excess belly fat was associated with higher triglyceride levels, increased ratios of total cholesterol to HDL cholesterol, and more insulin resistance (a diabetes risk factor).
Bottom line: Both studies support the notion that too much abdominal fat is harmful to the heart, even if your weight is normal. But the second study also points to a way to keep your waistline trim: regular exercise. As the fittest men had the least belly fat, exercise offers health benefits even when the scale indicates a healthy weight.
