Introduction: The current stroke guideline recommends moderate- to vigorous- intensity physical activity (PA) at least 40 min/d 3 to 4d/wk. But recent evidences suggest low-level PA can also reduce cardiovascular mortality. We assessed the benefits of a range of PA to prevent incident stroke in a Korean population.
Methods: From a prospective cohort data of National Health Insurance in Korea, we included 352896 individuals who received general health examination at 2009 and 2010. We excluded participants (1) with previous stroke (N=5917), (2) with incomplete data on PA (N=5155) and (3) disqualified due to death or emigration at the same year of examination (N=5498). Level of PA was assessed using questionnaire for frequencies of weekly PA in each of three intensity categories; light (≥30min/d; eg, walking), moderate (≥30min/d; eg, brisk walking) or vigorous (≥20min/d; eg, running). Moderate- to vigorous- intensity PA (MVPA) was classified into 4 categories; none, 1-2 times, 3-4 times, ≥5 times per wk. Cox proportional hazard regression was performed to assess the influence of each categories of MVPA on the risk of incident stroke.
Results: In 336326 individuals (171681 men and 164645 women) with an average follow-up of 3.6 years, 2213 incident stroke cases occurred (1866 ischemic stroke and 347 intracerebral hemorrhage). MVPA was none in 50%, 1-2 times/wk in 20%, 3-4 times/wk in 13%, and ≥5 times/wk in 18% of the cohort. Multivariable analysis (adjusted for age, sex, income, alcohol, smoking, light intensity PA, hypertension, diabetes and hyperlipidemia) showed even individuals in MVPA 1-2 times/wk group had a 16% reduced risk of incident stroke (HR: 0.84, 95% CI: 0.73-0.96) compared with those in none MVPA group. MVPAs 3-4 and ≥5 times/wk were also associated with lower risk of incident stroke (0.79, 0.68-0.91 in 3-4 times/wk; 0.79, 0.70-0.89 in ≥5 times/wk). Similar results were observed in ischemic stroke, but not in intracerebral hemorrhage.
Conclusions: Even 1-2 times a week of MVPA might be beneficial to prevent first-ever stroke in general population. From a public health perspective we need to encourage inactive people to do exercise with more achievable goal, considering 50% of individuals in this cohort were still physically inactive.