Physical activity cuts stroke risk

There is good evidence that regular physical activity reduces the risk for cardiovascular disease (1). However, the protective effect of physical activity specifically on stroke risk is less clear, and the results are inconsistent.

Study Results

Some studies (2-7), but not all (8-11) have indicated a significant inverse association between leisure-time physical activity and stroke risk. Moreover, studies on women are sparse (4-7, 11), and only three of them have found a significant inverse association between leisure-time physical activity and stroke risk (5-7). Small sample sizes and few stroke events, especially among women, may have contributed to the inconsistent observations.

In addition, it is not clear whether other types of physical activities, such as occupational and daily commuting physical activity on foot or by bicycle, are independently related to the risk of stroke. These studies have focused on total stroke risk, and few studies have assessed the association between physical activity and different subtypes of stroke (3, 7, 8).

In the Honolulu Study (3), active men experienced a lower risk of subarachnoid hemorrhagic or intracerebral hemorrhagic stroke as compared with inactive men, but no significant association of physical activity on thromboembolic stoke risk was found.

In the Physicians’ Health Study (8), an inverse association of leisure-time physical activity on hemorrhagic stroke risk disappeared after adjustment for other confounding factors, and no significant association with ischemic stroke was present.

In the Nurses’ Health Study (7), regular leisure-time physical activity was associated with a reduced risk of ischemic stroke only, but not with subarachnoid hemorrhagic or intracerebral hemorrhagic stroke. These studies usually have a relatively small number of hemorrhagic stroke cases.

The FINRISK study: does physical activity reduce the risk of stroke?

The analyses from the FINRISK study also evaluated whether leisure-time, occupational, or commuting physical activity is independently associated with a reduced risk of total and different types of stroke (12).

We reviewed data on 47,721 Finns ages 25 to 64 years who did not have a history of coronary heart disease, stroke, or cancer. We completed questionnaires on smoking habits, alcohol consumption, socioeconomic factors, medical history, and physical activity during leisure time, at work and while commuting. During an average follow up of 19 years, 2,863 strokes (260 subarachnoid hemorrhage, 339 intracerebral hemorrhage, and 2264 ischemic) occurred.

After adjustment for age, gender, body mass index, blood pressure, cholesterol, education, smoking, alcohol consumption, diabetes and other two types of physical activity, we found that participants who described their leisure-time physical activity as moderate had a 14 percent lower risk of suffering any type of stroke than those whose activity level was low.

Similarly, participants who reported high leisure-time physical activity had a 26 percent lower risk of total stroke than those who had a low physical activity level.

Compared to participants with low activity levels, the risk of ischemic stroke was:

• 13 % lower for those who reported that they were moderately active during leisure times;
• and 20% lower among participants who said they were highly active.

Subarachnoid stroke risk was:

• 13 percent lower among participants with moderate activity;
• and 54 percent lower among those with high activity levels.

Intracerebral hemorrhage risk was:

• 23 percent lower for those with a moderate activity level;
• and 37 percent lower for those with a high activity level.

Lower stroke risk was also associated with increased amounts of physical activity while commuting. Compared to people without any activity while commuting to or from work, the risk of total stroke was 8 percent lower for those who were physically active for one to 29 minutes on their way to work each day (moderate) and 11 percent lower for people who were active for more than 30 minutes on their way to work (high). The risk of ischemic stroke was 7 percent lower for moderate commuting activity and 14 percent lower for high commuter activity.

There was no association between commuting physical activity and hemorrhagic strokes. Occupational activity had a modest association with ischemic stroke in the multivariate analysis.

The results revealed an inverse association between leisure-time physical activity and the risk of any stroke

The strengths of our study were the large sample size and in recording the largest number of strokes during its follow up. Not only leisure-time physical activity, but also occupational and commuting physical activities were included in the analysis. The results from our study revealed an inverse association between leisure-time physical activity and the risk of any stroke, including ischemic stroke, subarachnoid hemorrhage, or intracerebral hemorrhage. By increasing their physical activity during leisure time or commuting people can reduce their risk of stroke.

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.