One study suggested an increas- ing benefit with greater intensity in women (median relative risk [RR], 0.82 for all strokes for moderate-intensity versus no or light activity; RR, 0.72 for high-intensity versus no or light activity). In men, there was no apparent benefit of higher intensity (median RR, 0.65 for moderate intensity versus no or light activity; RR, 0.72 for high intensity versus no or light In contrast, the prospective Northern Manhattan Study (NOMAS) suggested that moderate- to high-intensity physical activity was protective against risk of ischemic stroke in men (hazard ratio [HR], 0.37; 95% CI, 0.18 0.78) but not Increased physical activity has also been associated with a lower prevalence of Vigorous physical activity, regardless of sex, was associated with a decreased incidence of stroke in the National Runners Health Study.119 The protective effect of physical activity may be partly mediated through its role in reducing BP120 and controlling other risk factors for CVD,121,122 including diabetes melli- and excess body weight. Physical activity also reduces plasma fibrinogen and platelet activity and elevates plasma tissue plasminogen activator activity and HDL cholesterol Physical activity may also exert positive health effects by increasing circulating anti-inflammatory cytokines, including interleukin-1 receptor antagonist and interleukin-10, and modulating immune function in addi- A large and generally consistent body of evidence from prospective, observational studies indicates that routine physi- cal activity prevents stroke. The 2008 physical activity guide- lines for Americans recommend that adults should engage in 150 min/wk of moderate-intensity (eg, fast walking) or 75 min/wk of vigorous-intensity aerobic physical activity (eg, running) or an equivalent combination of moderate- and vigorous-intensity aerobic activity. 