Theres no doubt about it: High-intensity exercise produces greater health benefits than low-intensity exercise. Real benefits, as in lowered mortality and heart-disease risk. Which isnt to say walking does nothing for you (it does). Running simply does more, as two major studies have proven recently:
Regular vigorous activity reduced mortality risk significantly among 17,000 men in the Harvard Alumni Study, according to an April 1995 report in the Journal of the American Medical Association. Non-vigorous activity (walking, for instance) had no such effect on mortality. The Harvard researchers found that the difference in mortality risk between those who did vigorous exercise and those who did very little was the same difference in mortality risk as those who were of ideal weight versus those who were at least 20 per cent over their ideal weight.
Among men, high-intensity exercise has a positive effect on all heart-disease factors, according to a German study of 12,000 people published recently. Cholesterol and triglyceride levels, blood pressure, heart rate and body weight were all improved by intense exercise. Among women in the study, high-intensity exercise was associated with lowered blood pressure, heart rate and body weight. For both men and women in the study, low-intensity exercise had far less effect on risk factors and, in some cases, had no effect at all.