Higher physical activity together with a healthy lifestyle have been shown to reduce the risk for cardiovascular diseases including stroke,1–2 while recent studies report that long‐term endurance sports practice is associated with an increased risk of atrial fibrillation (AF).3–5 It is generally believed that embolic ischemic stroke associated with AF is more severe and more often fatal, and survivors are left more disabled than patients with other causes of stroke.6
The Vasaloppet is the largest cross‐county ski race in the world. The race recruits both elite and recreational skiers. Among these skiers, a faster finishing time and a high number of completed races are associated with a future higher incidence of AF5 that may theoretically increase the risk for embolic stroke. Yet, in contrast, the participants in the Vasaloppet have a substantially lower mortality rate compared with the general population.7 There is a seemingly contradictory relationship between a high level off physical activity and risk of cardiovascular disease. Physically active and fit individuals appear to be protected against atherosclerotic artery disease8 but at the same time have a higher risk of volume and pressure overload in their left atrium, leading to an increased risk for AF,3–4 which may cause cardioembolic stroke.
We hypothesized that patients with a high level of physical activity prior to suffering stroke may have a lower risk of death, recurrent stroke, and myocardial infarction despite a higher incidence of AF. We also investigated whether these patients with a high level of physical activity suffer a less severe stroke with more favorable outcomes after stroke recurrence. Among patients with a high level of physical activity, we wanted to investigate whether there is a dose–response relationship between fitness and outcomes.