Dose-Response Association Between Level of Physical Activity and Mortality in Normal, Elevated, and High Blood Pressure

It has been a challenge to verify the dose of exercise that will produce the maximum health benefits in hypertension. This study aimed to explore the association between level of daily physical activity, all-cause mortality and cardiovascular outcome at different blood pressure levels. A random sample of 18 974 white men and women aged 20 to 98 years were examined in a prospective cardiovascular population study. Self-reported activity level in leisure-time was drawn from the Physical Activity Questionnaire (level I: inactivity; II: light activity; and III: moderate/high-level activity). Blood pressure was defined as normal blood pressure: <120/<80 mm Hg; Prehypertension: 120-139/80-89 mm Hg; Stage I hypertension: 140-159/90-99 mm Hg; Stage II hypertension >= 160/>= 100 mm Hg. The mean follow-up time was 23.4 +/- 11.7 years. At all levels of blood pressure, higher levels of physical activity were associated with lower all-cause mortality in a dose-response pattern. The pattern remained unchanged after adjustment for following confounders: sex, age, smoking status, education, diabetes mellitus, previous cardiovascular disease, body mass index, and calendar time. Compared with inactivity, following hazard ratios were found for stage I hypertension: light activity, hazard ratio 0.78 (0.72-0.84; P<0.001), moderate/high-level activity, hazard ratio 0.69 (0.63-0.75; P<0.001). At all levels of blood pressure, the risk of cardiovascular events was significantly reduced independent of the level of physical activity. In conclusion, the association between physical activity and all-cause mortality was present in an inverse dose-response pattern at all levels of blood pressure. Physical activity was associated with reduction in cardiovascular events independent of the level of physical activity.