Physical activity and cardiovascular disease risk in middle-aged and olderwomen

The authors investigated the relation between physical activity and cardiov ascular disease (CVD) in women by following 1,564 University of Pennsylvani a alumnae (mean age, 45.5 years), initially free of CVD, from 1962 until 19 93. Energy expenditure was estimated from the daily number of flights of st airs climbed and blocks walked as well as the sports played and was categor ized into approximate thirds (<500, 500-999, greater than or equal to 1,000 kcal/week). During 35,021 person-years, 181 CVD cases were identified. Aft er adjustment for coronary risk factors, the relative risks of CVD were 0.9 9 (95% confidence interval (CI): 0.69, 1.41) and 0.88 (95% CI: 0.62, 1.25) for women who expended 500-999 and greater than or equal to 1,000, respecti vely, compared with <500 kcal/week (p for trend = 0.45). Only walking was f ound to be inversely related to CVD risk (p for trend = 0.054). Compared wi th women who walked <4 blocks/day, the relative risks of CVD were 0.84 (95% CI: 0.59, 1.19) and 0.67 (95% CI: 0.45, 1.01) for women who walked 4-9 and greater than or equal to 10 blocks/day, respectively. Finally, an interact ion (p = 0.023) between body mass index and physical activity on CVD risk w as observed, with an inverse association only for leaner (<23 kg/m(2)) wome n. These data showed no overall association of physical activity with CVD r isk in women. However, walking greater than or equal to 10 blocks/day (appr oximately 6 miles (9.7 km)/week) was associated with a 33% decreased risk. One explanation for this finding may be that walking was reported more prec isely than other kinds of activities.