To exercise or not to exercise?
That is the question Mike Hauser, assistant research professor of medicine at the Center for Human Genetics, asked himself two years ago when he made the decision to participate in a ground-breaking exercise study at the Duke University Medical Center's Center for Living.
As a father of young children and as a genetics researcher who spends the majority of his time at work sitting in front of a computer screen, Hauser wanted to change his sedentary lifestyle and be able to once again play with his kids.
"The study targeted sedentary folks," Hauser said. "I'm on the faculty at Duke and I write and I sit in front of my computer all day, and there's not much activity in that. But now, it's nice to be able to get out and be more active with the kids--I have young kids--and it helps to be able to run with them."
Two years later, Hauser has lost 10 pounds in fat and continues the regular exercise regimen that he began as part of the DUMC study. Now, a healthier Hauser knows that the answer to his question clearly is to exercise.
The study in which he participated, dubbed Studies of Targeted Risk Reduction Interventions through Defined Exercise, was instigated by the questions of how much exercise is needed to prevent weight gain and how much is needed to lose weight, said primary investigator for the study and cardiologist Dr. William Kraus.
Supported by a $4.3 million grant from the National Heart, Lung and Blood Institute and published in the Jan. 12 issue of Archives of Internal Medicine, the trial provided the first scientific basis for moderate exercise as a method for preventing weight gain. In addition, the study found that any further exercise can lead to additional losses in weight and fat.
"It is common wisdom that the more exercise you do is better," said Kraus, who is also the director of clinical research at the Center for Living. "But nobody had done a controlled study... like this before."
For the study, researchers randomly placed 120 overweight and sedentary adults into one of four exercise groups. The control group was required not to do any exercise whatsoever; two groups, differing in the intensity of the workout, exercised the equivalent of either walking or jogging 12 miles per week; and a fourth, high dose and vigorous intensity group exercised the equivalent of jogging 20 miles per week.
Hauser was in the high dose, vigorous intensity group. This meant that his regimen consisted of burning 2,000 calories per week at 75 percent of his maximum exercise intensity. So at 6:30 a.m., four days a week, Hauser headed to the gym, where researchers monitored his performance and encouraged him to continue working out.
"It was gruesome at first," Hauser reminisced. "It was very difficult to get into it at first. But the nice thing was that during the studies, they had people at the gym for two hours in the morning and two hours in the evening--it was as if you had your own cheering section. They were like a surrogate for the nagging friend, who would not let you get away from exercising."
By measuring changes in weight, body composition and waist circumference, the researchers found that all participants who exercised, lost weight and those who exercised the equivalent of 20 miles per week, lost more than those exercising the equivalent of 12 miles per week. In particular, the high dose group experienced a 3.5 percent weight loss, the low dose group experienced a slightly greater than 1 percent weight loss while the control group showed a 1.1 percent weight gain. In order to isolate the weight effects of exercise from those of a diet, participants were encouraged not to alter their dietary habits.
Clinical Research Coordinator and member of the research team Brian Duscha emphasized the importance of exercise in order to prevent weight gain.
"Americans are very result oriented--whether you take a pill or exercise, people want to see results," Dusha said. "But if you don't do anything, you actually gain [weight]. People would say that's not a big deal but [over a lifetime] it creeps up on you. To prevent weight gain and not just weight loss is an important--perhaps even the most important--aspect of the paper."
Kraus just recently secured another five-year grant to continue this exercise research. In the upcoming research, 20 of the original participants--Hauser included--will continue to be monitored in order to explore at what intensity and what amounts they choose to exercise on their own volition. The future research will also integrate a resistance or weight lifting component into the study.
Although Kraus would not discuss the findings, he said he is encouraged by preliminary findings. "I promise the findings will be interesting, he said."
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