Does exercise lower my risk of stroke?
Yes, especially for the type of stroke caused by a blocked vessel ( ischemic stroke). Exercise reduces your stroke risk by the same amount that it reduces your risk of heart disease. This is not surprising since stroke and heart disease share many risk factors that exercise helps to control. Findings from the Nurses' Health Study of over 72,000 women aged 40 to 65 show that regular exercise can cut your risk of blocked-vessel stroke in half. Even moderate or brisk walking—done on a regular basis—reduces the risk of stroke by 30% to 50%.1
It has been known for a while that lifelong regular exercise—beginning at around age 15—is associated with up to a 70% reduced risk of blocked-vessel stroke later in life,2 but there is accumulating evidence that starting exercise in mid-life also helps. Increasing your level of activity by 3.5 hours per week can reduce your stroke risk by almost 40%, regardless of the age at which the increase is made.1
How does exercise protect against stroke?
Regular physical activity helps reduce risk factors for stroke (and heart disease) including high blood pressure, high cholesterol and triglycerides, diabetes, and obesity. If you already have these risk factors, being active can stop them from getting worse. Exercise also keeps your arteries flexible (stiff arteries are prone to clogging) and can reverse or stall the buildup of fatty plaque in blood vessels, which can lead to clots and stroke.3, 4 If you are not used to regular exercise, talk to your doctor before starting an exercise program because the risk of heart attack and stroke may increase during and immediately after strenuous exercise.
A study involving nearly 30,000 women (ages 45 to 90) from the Women's Health Study finds that almost 60% of the effects of exercise on cardiovascular risk reduction are due to changes in known risk factors, mostly inflammatory blood markers and high blood pressure. Lowering inflammatory blood markers through exercise reduced risk of heart disease and stroke by 33%, and lowering blood pressure reduced risk by 27%.5
Another major risk factor for stroke is obesity. Adopting a healthy lifestyle, including exercise, to get to a healthy weight is the best way to modify this risk. Women with a BMI greater than 30 have a 72% increased risk of blocked-vessel stroke in comparison to women with a BMI less than 25.6
Exercise also reduces the likelihood of developing type 2 diabetes—a major risk factor for stroke—by increasing the body's sensitivity to insulin. This in turn makes it easier for your body to maintain suitably low blood sugar levels.1
How much exercise do I need?
The amount of exercise that you need for optimal control of your stroke risk factors generally depends on how intense the exercise is. The good news is that studies show that any exercise at all appears to reduce stroke risk, and the more you exercise the more your risk decreases.7
A large study of about 1000 people (57% women) looked at the effects of both light and moderate-to-heavy exercise on stroke risk. The average age of participants was 69, and the average amount of exercise they got was 4 to 5 hours/week. Researchers found that any form of exercise reduced stroke risk in all groups, but both higher intensity exercise and longer periods of any exercise translated to a lower stroke risk. Light activity reduced risk by 61%, and moderate-to-heavy exercise reduced risk by 77%. Less than 2 hours of exercise per week was associated with a 58% risk reduction, while exercising for more than 5 hours per week was associated with a 69% risk reduction. "Light-moderate" exercise included walking, calisthenics, dancing, golf, bowling, horseback riding, and gardening. "Heavy" exercise included hiking, tennis, swimming, bicycle riding, jogging, aerobic dancing, handball, racquetball and squash.8
Will I benefit from exercise if I already had a stroke?
Exercise may help to prevent recurrent stroke, and it can aid stroke recovery. After a stroke, many patients, especially the elderly, have a decreased tolerance for physical activity that could be due to limited range of movement, depression, or fatigue from lack of exercise during the recovery period. Research studies show that aggressive rehabilitation beyond the usual 6-week period increases aerobic capacity and motor function in stroke patients, and an aerobic exercise program can improve multiple cardiovascular risk factors. Compared with “usual” stroke care and recovery, an exercise-intensive program can lead to better outcomes in patients' endurance, balance, and mobility.9, 10
The key to preventing further strokes is the control of your risk factors by lifestyle modification and medication. Current data suggest that less than half of stroke patients have their risk factors adequately controlled for preventing another stroke.9 One of the most prevalent risk factors that persist after stroke is high blood sugar. Many people who suffer stroke in the first place have diabetes, a major risk factor for stroke. In addition, a paralyzing stroke makes it harder for subsequently weaker muscles to metabolize sugar ( glucose), which contributes to insulin insensitivity and high blood sugar, thereby increasing the risk of recurrent stroke. Improving sugar metabolism is therefore crucial to staving off further strokes.
Preliminary studies suggest that exercise may be one way of improving sugar metabolism. A small study of 12 stroke patients with abnormal sugar metabolism found that 6-month exercise therapy improved two measures of abnormal blood sugar—glucose intolerance and insulin response—in 7 (58%) patients, compared with only 1 of the non-exercising patients. Fasting insulin levels decreased by 23% in 6 months in the exercising group, compared with an increase of 9% for the non-exercisers.11 Larger studies are needed to confirm these results.
You should talk to your health care provider before beginning an exercise program if you:
- Have heart disease, have had a stroke, or are at high-risk for either
- Are middle-aged (45 to 50) or older and currently inactive
- Have diabetes or are at high risk for it
- Take blood pressure medication
- Are obese (body mass index [BMI] of 30 or more)
- Are pregnant
- Have a medical condition or disability that may affect your ability to exercise (for example, knee problems, arthritis)
See the next page for more information about types of exercise and how to get started on an exercise program.