Physical activity has been shown to reduce the risk for cardiovascular disease, possibly in part by decreasing blood pressure. The level of physical activity needed to reduce blood pressure includes brisk walking; however, the value of mild physical activity, such as routine walking, is less clear. Hayashi and associates studied the relationship between mild physical activity, specifically walking to work and leisure-time physical activity, and the risk for hypertension.
The Osaka Health Survey is an ongoing cohort study of risk factors for chronic disease. All male employees of a gas company in Osaka underwent detailed clinical examinations and completed questionnaires on health-related behaviors, including exercise. Specifically, the questionnaires elicited information about leisure-time physical activity, duration of the walk to work, nature of occupation, alcohol consumption and smoking habits. The study sample of 6,017 men was followed for six to 16 years, excluding those with diagnosed hypertension or borderline hypertension, diabetes or impaired glucose tolerance.
During the 59,784 person-years of follow-up between 1981 and 1997, hypertension developed in 626 men. Men whose walk to work was 21 minutes or more had a decreased risk for incident hypertension compared with men whose walk was 10 minutes or less. Men who engaged in leisure-time physical activity at least once weekly had a lower relative risk of hypertension than those who did not. However, there was no relationship between a longer walk to work and a more active life style.
The authors conclude that the duration of the walk was associated with a decreased risk for incident hypertension, even after adjustment for age, body mass index, alcohol consumption, leisure-time physical activity, smoking status, systolic or diastolic blood pressure at baseline, and fasting plasma blood glucose. Regular physical activity at least once weekly was inversely related to the incident risk of hypertension. Physicians should recommend walking to work as an adjunct to weight control, reduction of alcohol consumption and increased leisure-time physical activity. Women were not included in this study, so it is uncertain whether these results apply to them as well.