Fatness, despite fitness, is linked with cardiovascular risk factors

Body fatness was associated with more cardiovascular disease risk factors even among healthy, aerobically fit men, according to a report today in an obesity-themed issue of Circulation: Journal of the American Heart Association.

A study of 135 healthy men who varied widely in body fatness and aerobic fitness found that fatness was consistently associated with a wide variety of established cardiovascular disease risk factors, while fitness was associated with only selective risk factors.

“Our results provide further evidence implicating body fatness as a public health concern,” said lead author Demetra D. Christou, Ph.D., a research associate in the Department of Integrative Physiology at the University of Colorado at Boulder.

Although regular physical activity may help prevent cardiovascular disease (CVD), excessive body weight increases the risk of developing CVD.

“Elevated body fatness is associated with an adverse profile of cardiovascular disease risk factors independent of aerobic fitness,” Christou said. “Our findings provide additional justification for risk-factor management strategies that emphasize prevention of weight gain in normal weight men and successful, long-term weight reduction in overweight and obese men.”

Previous studies probing the importance of fatness versus aerobic fitness had conflicting results.

Christou and colleagues examined the unique contributions of fatness and aerobic fitness to cardiovascular disease risk factors in a group of healthy men with a broad range of body fat, aerobic fitness and age. They studied 135 volunteers, ages 20 to 79, all of whom had passed a rigorous health screening that excluded men with such problems as high blood pressure, overt coronary heart disease, irregular heartbeats and men who smoked or were taking any medications.

Researchers measured established CVD risk factors such as blood cholesterol, triglycerides, large artery “stiffness” and naturally occurring blood clotting molecules and clot inhibitors. They assessed aerobic fitness by measuring each volunteer’s maximal oxygen consumption during a treadmill test. Fatness was assessed by body mass index (BMI), derived by dividing weight in kilograms by height in meters squared; waist circumference — an estimate of intra-abdominal fat content; and total percent body fat. Participants’ BMI ranged from 20–39 kg/m2 (25 and over is considered overweight). Study participants included men who were aerobically fit but who also had higher levels of fatness.

The team found that overall fatness was more strongly and consistently associated with cardiovascular disease risk factors than lack of aerobic fitness. The study has several important implications:

“First, men who are overweight or obese should be encouraged to reduce body fatness, regardless of their aerobic fitness,” the authors wrote. “Second, weight management and prevention of excess adiposity should be a primary cardiovascular health goal for men. Third, men who are sedentary should be encouraged to increase their physical activity and improve aerobic fitness, regardless of their body fatness.

“Most importantly, our results support the position that habitual physical activity and aerobic fitness should be viewed as an effective partner to weight maintenance in the primary prevention of cardiovascular disease, but not a surrogate approach.”

The study has several important limitations. It had a cross-sectional design, meaning participants were only observed at one point in time. Researchers did not explore the impact of fatness and fitness on cardiovascular disease or cardiovascular death, and the study included only generally healthy men.

Co-authors are Christopher L. Gentile, M.S.; Christopher A. DeSouza, Ph.D.; Douglas R. Seals, Ph.D.; and Phillip E. Gates, Ph.D.

The National Institutes of Health funded the study.