Background and purpose: Physical activity has generally been inversely related to the risk of developing stroke, but details regarding the amount and kinds of activity required are unclear as are associations for specific stroke subtypes.
Methods: Eligible subjects were 39 315 healthy US women, > or =45 years of age, from the Women's Health Study. Women reported physical activity at baseline (1992 to 1995) and at 36, 72, 96, 125, and 149 months' follow-up. During an average follow-up of 11.9 years, 579 women developed incident stroke (473 ischemic, 102 hemorrhagic, and 4 of unknown type). Proportional hazards models related physical activity, updated over time, to the risk of incident stroke.
Results: The multivariable relative risks associated with <200, 200 to 599, 600 to 1499, and > or =1500 kcal/week of leisure-time physical activity were 1.00 (referent), 1.11 (95% CI, 0.87 to 1.41), 0.86 (95% CI, 0.67 to 1.10), and 0.83 (95% CI, 0.63 to 1.08), respectively (P trend=0.06). Similar results were observed for ischemic stroke, whereas no associations were observed for hemorrhagic stroke. Vigorous physical activity was not related to stroke risk (P trend=0.50); however, walking time and walking pace were inversely related, either significantly or with borderline significance, to total, ischemic, and hemorrhagic stroke risks (P trend between 0.002 and 0.07).
Conclusions: This study shows a tendency for leisure-time physical activity to be associated with lower stroke risk in women. In particular, walking was generally associated with lower risks of total, ischemic, and hemorrhagic stroke.