Sedentary lifestyle cancels out heart benefits of having a normal weight for adults, UF study finds

Starting to slip with your New Year’s resolution to exercise more? A new University of Florida study may provide some motivation.

Researchers have found that low levels of physical activity can put healthy weight adults at the same risk for cardiovascular disease as adults who are overweight.

“Our study demonstrates that a sedentary lifestyle counters the benefit of being at a normal weight when it comes to heart disease risk,” said lead investigator Arch G. Mainous III, Ph.D., chair of the department of health services research, management and policy in the UF College of Public Health and Health Professions, part of UF Health. “Achieving a body mass index, or BMI, in the normal range shouldn’t give people a false sense of confidence they’re in good health. If you’re not exercising, you’re not doing enough.”

The study, which appears online ahead of print in the American Journal of Cardiology, found that 30 percent of U.S. adults at a normal weight are at increased risk of heart attack or stroke. These adults had higher levels of belly fat, shortness of breath upon exertion, unhealthy waist circumference or less than recommended levels of physical activity, the UF researchers say.

“We have traditionally thought that people with a normal BMI are healthy and at low risk for heart disease, but increasingly we are finding that how much you weigh is not necessarily a measure of good health,” said Mainous, the Florida Blue endowed chair of health administration. “Sedentary lifestyle markers may play a better role in predicting cardiovascular disease risk.”

For the study, the investigators analyzed data from the National Health and Nutrition Examination Survey, a nationally representative study that collects data from a combination of interviews, physical examinations and laboratory tests. The study focused on participants ages 40 to 79 who did not have a previous diagnosis of coronary heart disease, stroke or heart attack.

Researchers examined participants’ sagittal abdominal diameter, which is a measure of fat in the gut region, and waist circumference as well as self-reports on the amount of moderate to vigorous physical activity, the amount of time spent sitting and whether they experienced shortness of breath either when hurrying or walking up a slight hill.

In addition, researchers calculated the American College of Cardiology and the American Heart Association, or ASCVD risk score, of participants. The ASCVD risk score uses weighted variables, including age, sex, race/ethnicity, smoking status, diabetes status, cholesterol, blood pressure and blood pressure medication status, to calculate individuals’ risk of having a heart attack or stroke within the next 10 years. A score of 7.5 percent or higher is considered high risk.

The investigators found the rate of high ASCVD risk score among people who are overweight was similar to the rate among people who had a normal BMI, but had indicators of a sedentary lifestyle.

For those looking to increase their activity level, Mainous suggests reviewing the Centers for Disease Control and Prevention’s physical activity guidelines, which recommend at least 150 minutes of moderate intensity exercise a week for adults. Exercise should include a combination of aerobic activity and strength training.

In addition to Mainous, the study team included Rebecca Tanner, M.A., a research coordinator, and Ara Jo, Ph.D., a clinical assistant professor, both from the UF department of health services research, management and policy; Kiarash P. Rahmanian, M.P.H., of the College of Medicine at the University of North Carolina, Chapel Hill; and Peter J. Carek, M.D., M.S., a professor and chair of the department of community health and family medicine at the UF College of Medicine.