Indiana University researchers studied 730 highly active people, ages 20 to 93, to see how their physical and mental quality of life and rates of obesity-related diseases compare to the general population. Their study participants, United States Master Swimmers, reported swimming regularly for an average of 18.6 years. The percentage of Master Swimmers classified as obese (5.4 percent) and the prevalence of obesity-related diseases such as hypertension (6.5 percent), diabetes (1 percent) and coronary artery disease (1.3 percent), was significantly less than the general population. Their measures of physical and mental quality of life also were significantly better than the general public, with the typical decline in physical quality of life occurring later for them — around the age of 55. Jeanne Johnston, assistant professor in IU’s Department of Kinesiology, said research involving physical activity and obesity-related diseases typically begins by looking at sedentary people and uses this population to establish baseline data, rather than examining active people who could represent model behavior. “The low incidence of overweight and obesity as well as the self-reported diseases demonstrates that active engagement in physical activity improves both physical and mental health as well as the diseases people might have,” she said. Examining highly active people, Johnston and her colleagues wrote, might lead to a better understanding of the relationship between lifelong physical activity, successful aging, morbidity and quality of life.