BOSTON, MASSACHUSETTS - It is generally accepted that regular, vigorous exercise reduces the risk of heart attack and death from coronary heart disease (CHD). Most of the studies on this association have involved men and little information is available as to whether women also achieve protection from physical activity and if so, how vigorous an exercise level is required.

A group of researchers at Harvard Medical School set out to answer these questions in 1986 and have just released their report. The study involved 72,488 female nurses who were between the ages of 40 and 65 years in 1986. The nurses completed questionnaires about their physical activity level in 1986, 1988, and 1992. After eight years of follow-up 475 of the nurses had suffered a non-fatal heart attack while 170 had died from CHD. For purposes of analysis the women were divided into five groups according to their physical activity level. Women in the first quintile were essentially sedentary while women in the highest (fifth) quintile either exercised vigorously for at least 1.5 hours per week or walked briskly for three hours or more every week.

Both vigorous exercise and brisk walking reduced the risk of a non-fatal heart attack or death from CHD between 30 and 40 per cent when results were adjusted for all other factors known to influence the risk of heart disease. Although not dealt with in any detail in the study report it is of interest to note that the women in the high activity group were more likely to be taking vitamin E supplements (19.4 per cent of the women in the high activity group vs. 12.8 per cent in the sedentary group) and were less likely to be smokers (17.5 per cent in the high activity group vs. 28.2 per cent in the sedentary group).

Source - New England Journal of Medicine, Vol. 341, August 26, 1999, pp. 650-58