The key to these conflicting results could lie in the genetic makeup of the exercisers. A joint research project of The University of Texas Health Science Center at Houston and the University of Houston will explore that issue over the next five years under a $3.2 million grant from the National Institute of Diabetes and Digestive and Kidney Disease of the National Institutes of Health.
"This will be the largest, most racially and ethnically diverse study ever conducted of how genes may influence a person's response to exercise," said project principal investigator Molly Bray, Ph.D., assistant professor of biological sciences in the UT School of Public Health's Human Genetics Center. "If we can determine the genes involved, then we might be able to prescribe an exercise program that fits a person's individual needs, one that really works for them and is easier to stick with."
Sixty percent of U.S. adults are overweight and half of those are obese, subjecting them to higher risk for hypertension, type 2 diabetes, cardiovascular disease, stroke and cancer. While exercise and diet are often generally prescribed, success with either is highly variable, Bray said.
Deanna Hoelscher, Ph.D., associate professor of nutrition at the School of Public Health, is a co-investigator. At UH, the lead investigator is Andrew Jackson, Ph.D., professor of health and human performance. Brian Sekula, Ph.D., and Jill Bush, Ph.D., both assistant professors of health and human performance also are involved in the study.
The study, Training Interventions and Genetics of Exercise Response (TIGER), offers UH students who volunteer to participate an opportunity to get in shape, and learn about their body composition and fitness while earning academic credit. The project will take student volunteers through a closely monitored 30-week exercise program that includes state-of-the-art evaluation of body composition, blood pressure, and blood chemistry (cholesterol levels, blood sugar, etc) before, midway, and at the end of the 30 weeks.
"The common method overweight people use to lose weight is some form of diet, but research shows that diets fail to keep weight off," Jackson said. "The TIGER study uses a well-established exercise program that has been shown to educate students about how to exercise for fitness and control. A web-based computer program that computes energy expenditure lets the students know exactly how many calories are being burned up by their exercise."
Starting this month, one cohort of 384 volunteers will be enrolled each fall semester for the next four years, for a total of 1,536 participants. Researchers will analyze the effect of variation in genes involved in fat tissue formation, muscle development and growth, energy metabolism and eating behavior in relation to changes in body mass and composition, fat distribution, obesity status, blood chemistry, blood pressure and heart rate of volunteers after 30 weeks of exercise.
UH students who volunteer for the study will enroll in special sections of Exercise for Health and Fitness, a three-day-a-week class that involves 30 minutes of aerobic exercise each period along with one mini-presentation on aspects of fitness and exercise each week.
Completion of the 30-week study requires enrollment in the class in the spring semester as well. Any volunteer is free to withdraw from the research study at any time while remaining in the class if they desire. Federally mandated procedures to protect the confidentiality of volunteers' information will be used.
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