Increased Fitness Level Fights Metabolic Syndrome

Fitness

Moderate and higher levels of cardiorespiratory fitness are associated with a significantly lower risk of developing metabolic syndrome in adults, researchers report in Circulation: Journal of the American Heart Association.

Metabolic syndrome is a cluster of cardiovascular disease and diabetes risk factors including excess body weight, high blood pressure, elevated triglycerides, low levels of high-density lipoprotein (HDL) and high fasting glucose levels. The presence of three or more of the risk factors increases a person's risk of developing diabetes and cardiovascular disease.

"Our data suggest higher fitness levels provide protection against metabolic syndrome even in individuals with increased susceptibility because of existing metabolic risk factors," said lead author Michael J. LaMonte, Ph.D., M.P.H., director of The Cooper Institute's Epidemiology Division in Dallas, Texas.

"Although genetics contribute to individual fitness levels, previously published data indicate that most people can achieve moderate levels of cardiorespiratory fitness through 30-40 minutes of brisk walking about five days per week. The highest level of fitness is likely to be achieved through vigorous jogging, running, biking or swimming for 20 to 30 minutes a day about three to five days a week, which brings even more protective benefits," he said.

Researchers based their findings on 9,007 men and 1,491 women participating in the Aerobics Center Longitudinal Study, a prospective epidemiological study led for 20 years by senior author Steven N. Blair, P.E.D.

Cardiorespiratory fitness levels were determined objectively by a maximal treadmill performance test rather than self-reported physical activity relying on subjective memory, an important component of the study, LaMonte said.

Men and women were analyzed separately and each group was divided into three fitness levels: the upper third or high fitness level; middle third or moderate fitness level and lower third or low fitness level.

In men, the risk of metabolic syndrome was 26 percent lower for those who were moderately fit and 53 percent lower for those who were highly fit, compared to those in the lowest fitness category.

In women, the risk of metabolic syndrome was 20 percent lower for those who were moderately fit and 63 percent lower for those who were highly fit, compared to those in the lowest fitness category.

The overall study population was predominantly Caucasian, and the average age was 44. All were evaluated for metabolic risk factors at baseline and follow-up examinations.

"The protective effect of fitness was observed in women and men and remained significant even after adjustment for the number of baseline metabolic syndrome factors," LaMonte said.

Of the total study population, 1,346 men developed metabolic syndrome during 5.7 years of follow-up, while 56 women developed metabolic syndrome during the same follow-up.

These findings extend existing data by demonstrating that moderate and high levels of fitness substantially protects against developing metabolic syndrome in women and men.

"Promoting higher levels of cardiorespiratory fitness, through greater physical activity may be the most prudent clinical and public health strategy for the primary prevention of metabolic syndrome," he said.

LaMonte called on physicians to consider the potential benefits of greater cardiorespiratory fitness in the primary prevention of metabolic syndrome in patients who have components of the metabolic syndrome.

Co-authors are Carolyn E. Barlow, M.S.; Radim Jurca, Ph.D.; James B. Kampert, Ph.D.; Timothy S. Church, M.D., Ph.D.; and Steven N. Blair, P.E.D.

The study has been funded for 20 years by the National Institutes of Health.

Statements and conclusions of study authors that are published in the American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect association policy or position. The American Heart Association makes no representation or warranty as to their accuracy or reliability.

Editor's note: The American Heart Association's Choose To Move is a FREE 12-week program to help women increase physical activity and build healthy habits to lower their risk for heart disease and stroke. It's part of the American Heart Association's Go Red For Women movement to raise awareness that cardiovascular disease is the No. 1 killer of women and to help women take steps to prevent heart disease and stroke. To register for the program, call 1-888-MY-HEART or visit http://www.americanheart.org/choosetomove - DALLAS, July 12