October 28, 2008 — Although any type of exercise is beneficial for health, high-intensity exercise is likely necessary to achieve significant improvements in body composition, according to a University of Virginia study led by Curry School of Education professor Arthur Weltman.
Findings of the study, which involved 27 middle-aged obese women with metabolic syndrome — a group of risk factors that includes abdominal obesity, unhealthy cholesterol levels, high blood pressure, elevated triglycerides and elevated fasting glucose — will be published in the November issue of Medicine & Science in Sports & Exercise, the journal of the American College of Sports Medicine.
In the study, which did not involve diet intervention, the women were divided into three groups. Seven of the women did not change their activity levels; 11 performed low-intensity exercise five days per week; and nine performed low-intensity exercise two days per week and high-intensity exercise three days per week. Low-intensity exercise involved walking, Weltman said. High-intensity exercise was walk-jogging and jogging.
The high-intensity group reduced total abdominal fat, subcutaneous abdominal fat and visceral abdominal fat during the 16-week exercise period. Visceral fat surrounds the organs (e.g. liver and kidneys), Weltman explained, and excessive amounts are associated with the development of diabetes, heart disease and high blood pressure.
"Improving body composition can improve overall health and quality of life, and exercise-induced reductions in total and visceral abdominal fat can significantly lower the risk of chronic disease," Weltman said.
"For obese women entering the middle and later stages of life, reducing internal abdominal fat or preventing too much of it forming is crucial," he said. "Exercise, especially vigorous exercise, may be the best way to do it.
"High-intensity exercise was prescribed based on each individual's capabilities and allowed each woman to complete the exercise bouts. Often, people think they cannot engage in high-intensity exercise because they associate it with what athletes are able to do, not what is high-intensity for them. It varies from person to person," Weltman said.
He stressed, however, that simply starting an exercise program is important to begin working toward changing body composition.
The American College of Sports Medicine and the American Heart Association recommend that healthy adults 18 to 65 years old need moderate-intensity aerobic physical activity for at least 30 minutes five days each week or vigorous-intensity aerobic physical activity for at least 20 minutes three days each week. However, overweight and obese persons may need up to 300 minutes of exercise per week to lose weight.
For those new to exercise, the American College of Sports Medicine has created resources for getting started at www.acsm.org/physicalactivity.
Weltman's study, "Effect of Exercise Training Intensity on Abdominal Visceral Fat and Body Composition," was funded with a grant from the National Institutes of Health through the U.Va. General Clinical Research Center.
Other members of Weltman's research team include Brian Irving of the Mayo Clinic, Dr. Chris Davis of the University of California-San Diego's School of Medicine, David Brock of the University of Vermont and U.Va. faculty members Judy Weltman, Glenn Gaesser and Dr. Eugene Barrett, and U.Va. doctoral student Damon Swift.
"We currently have several ongoing projects that examine the effects of intensity of exercise on clinical outcome measures, including endothelial function, as well as glucose disposal after an oral glucose tolerance test," Weltman said.
The American College of Sports Medicine is the largest sports medicine and exercise science organization in the world. More than 35,000 international, national and regional members and certified professionals are dedicated to advancing and integrating scientific research to provide educational and practical applications of exercise science and sports medicine.