A prospective study of walking as compared with vigorous exercise in the prevention of coronary heart disease in women

Background The role of walking, as compared with vigorous exercise, in the prevention of coronary heart disease remains controversial, and data for wo men on this topic are sparse. Methods We prospectively examined the associations between the score for to tal physical activity, walking, and vigorous exercise and the incidence of coronary events among 72,488 female nurses who were 40 to 65 years old in 1 986. Participants were free of diagnosed cardiovascular disease or cancer a t the time of entry and completed serial detailed questionnaires about phys ical activity. During eight years of follow-up, we documented 645 incident coronary events (nonfatal myocardial infarction or death from coronary dise ase). Results There was a strong, graded inverse association between physical act ivity and the risk of coronary events. As compared with women in the lowest quintile group for energy expenditure (expressed as the metabolic-equivale nt [MET] score), women in increasing quintile groups had age-adjusted relat ive risks of 0.77 0.65, 0.54, and 0.46 for coronary events (P for trend <0. 001). In multivariate analyses, the inverse gradient remained strong (relat ive risks, 0.88, 0.81, 0.74, and 0.66 for women in increasing quintile grou ps as compared with those in the lowest quintile group; P for trend = 0.002 ). Walking was inversely associated with the risk of coronary events; women in the highest quintile group for walking, who walked the equivalent of th ree or more hours per week at a brisk pace, had a multivariate relative ris k of 0.65 (95 percent confidence interval, 0.47 to 0.91) as compared with w omen who walked infrequently. Regular vigorous exercise (greater than or eq ual to 6 MET) was associated with similar risk reductions (30 to 40 percent ). Sedentary women who became active in middle adulthood or later had a low er risk of coronary events than their counterparts who remained sedentary. Conclusions These prospective data indicate that brisk walking and vigorous exercise are associated with substantial and similar reductions in the inc idence of coronary events among women. (N Engl J Med 1999;341:650-8.) (C) 1 999, Massachusetts Medical Society.