A brisk walk seems to be a better option than running fast when it comes to losing weight. People should mix moderate and vigorous cardiovascular exercises, as well as strength training to get the greatest health and fitness benefits. Losing weight basically means to burn more calories than one takes. But it hasn't been clear whether the intensity of a regular workout makes a difference in body composition - that is, the proportions of fat and lean tissue. Researchers from the Aristotle University of Thessaloniki in Greece found that among 14 women who embarked on a three-month exercise regimen, those who worked out at a moderate pace lost more weight than those who exercised more intensively. But this doesn't mean that fast runners should slow down. Women in the higher-intensity exercise group did retain more muscle mass than those who worked out more moderately. The researchers randomly assigned 14 normal-weight and overweight women to one of two groups: one that exercised on a treadmill at a moderate pace, four times a week; and other that worked out at a more vigorous clip, also four times per week. They then set the duration of the workouts so that women in both groups would burn 370 calories each time. After three months, exercisers in both groups were slimmer, but the lower-intensity group lost more weight - about 7 pounds, on average as compared to the 4 pounds in the high-intensity group. Fat-free mass decreased slightly (less than half a pound) in the low-intensity exercisers and increased slightly (about 1 pound) in the high-intensity group. It's possible, that women in the high-intensity group shed fewer fat because they ended up eating more, or were so drained by their regimen that they relaxed more in their leisure time. In turn, the women might have held on to more muscle simply because they lost less weight. On the other hand, high-intensity exercise may actually spur some growth in muscle fibres. The findings suggest that people should stay active with various forms of exercise. But for those who want to know whether they're working hard or moderately, a heart rate monitor or simple pulse checks during the workout will provide this information.
International Journal of Sports Medicine,
April 2006