American College of Sports Medicine, May 28-31, 2008
The American College of Sports Medicine's 55th Annual Meeting took place May 28-31 in Indianapolis, and presented more than 200 sessions and 2,000 abstracts. Key topics included the ongoing epidemic of physical inactivity and strategies to reduce it such as "Exercise Is Medicine," a joint initiative between the American College of Sports Medicine (ACSM) and the American Medical Association. New studies showed how exercise can improve health measures in morbidly obese patients, and help prevent or control diabetes in women and adolescents.
Barbara E. Ainsworth, Ph.D., of the University of South Carolina in Columbia, S.C., delivered a President's Lecture in which she called for public health approaches to reach the 50 percent of Americans who do not get enough physical activity to produce even minimal health benefits. "Of the four modifiable risk factors for coronary heart disease, one is physical inactivity," she said in a statement. "Essentially, half of the U.S. population is throwing caution to the wind, and that's why physical inactivity has become a public health issue."
Public officials need to create a more exercise-friendly environment with more free or low-cost parks and recreational facilities, sidewalks and bike trails, she said. She also urged communities to embrace physical education in schools and housing policies that encourage more people to walk to work.
Encouraging people to exercise is the key, she said. "Our greatest teacher in improving the physical activity of this nation is our experience with tobacco. Through high-quality research, coordinated mobilization, legislative changes and impacting policy, we have been able to slow down tobacco usage."
Physicians can play a vital role in fighting physical inactivity, ACSM president Robert E. Sallis, M.D., said in a statement: "Americans would be astounded to see how much difference a brisk 30-minute walk a few times a week makes in their overall health. We encourage physicians to talk to their patients about the importance of exercise and to work with them to establish programs they can start today and continue through their lives."
Launched in late 2007, the "Exercise Is Medicine" initiative encourages physicians to record physical activity as a vital sign during patient visits, educate patients about the health benefits of exercise, and advise patients to get at least 30 minutes of physical activity and 10 minutes of stretching and light muscle training five days per week.
Three new studies presented at the meeting showed that exercise benefits obese, hypertensive patients. In one study, researchers were able to get 14 morbidly obese patients to achieve at least 70 percent of their maximum heart rate with brisk walking, suggesting that brisk walking alone is an effective aerobic training stimulus.
The two other studies demonstrated that 30 minutes of brisk walking at 50 percent intensity helped reduce blood pressure for at least four hours in borderline hypertensive middle-aged men, and that one 40-minute session of brisk walking or four 10-minute sessions of brisk walking effectively reduced blood pressure in 23 hypertensive men. "Those with time crunches and busy schedules can fit bits of exercise in through the day to reap healthy benefits," Saejong Park, Ph.D., of South Korea, said in a statement.
Several studies addressed the strong link between physical inactivity and diabetes. In one study, researchers assessed 6,200 women over a period of 17 years. They found that the least-fit women were three times as likely to develop diabetes as the most-fit women, while those with the highest body mass index (BMI) scores were six times as likely to develop the disease as those with the lowest BMI scores.
"One of the more remarkable findings is that a mild to moderate level of aerobic fitness was associated with a substantially reduced risk of diabetes in these women," Stephen P. Hooker, Ph.D., of the University of South Carolina, said in a statement. "These levels of fitness can be achieved by most women by simply walking briskly for 30 minutes five days per week. This amount of regular physical activity will also play an important role in maintaining a healthy body weight, further lowering the risk of diabetes."
Two other studies showed that maximal oxygen consumption was below the 10th percentile in nearly all of 40 adolescent subjects with type 2 diabetes, and that a higher fitness level was the strongest predictor of better metabolic control in more than 100 adolescents with either type 1 or type 2 diabetes.
One of the most intriguing studies presented at the meeting suggested that a simple intervention could help prevent the weight gain of five pounds or more that typically occurs between Thanksgiving and New Year's Day. Sukho Lee, Ph.D., of Texas A&M International University, and colleagues conducted pre-holiday and post-holiday screenings of 19 university faculty and staff (11 women and eight men). During the holidays, the subjects were instructed to keep a diet log.
Although the subjects increased their average daily dietary intake during the holidays from 1,707 to 2,326 calories, there were no significant changes in body weight, percent body fat, or measures of cardiovascular fitness when the subjects were screened several weeks after the holidays. "We assume that they gained weight but were determined to lose it," Lee said in a statement.
Lee suggested that such health screenings could be a powerful weight-control tool. "It's a subconscious effect," he said. "You know someone is watching."