Cardiovascular Risk Factors and Physical Activity: How Much Is Enough?

In reply

We appreciate the comments by Messerli et al and the information about an inverse relationship between physical activity and certain cardiovascular risk factors. However, they suggest a possible undefined upper limit of the dose response curve between physical activity and most cardiovascular risk factors. However, we observed, when stratifying by age, a U-shaped relationship between sustained physical activity and systolic blood pressure for certain age groups. This pattern was especially evident among men 40 to 49 years old at study entry after 7 years of increasing levels of leisure time activity (Table 1). This finding indicates a higher level of physical activity effect on systolic blood pressure. Among women, the high and very high activity level were merged (few women reported a very high activity level), and the U-shaped relationship was less marked. This U-shaped relationship was not observed after 7 years among those 30 to 39 years old at entry; for this age group our results corroborate with other studies of the same age group.¹ In contrast, this age-related U-shaped relationship was not observed between physical activity and diastolic blood pressure for either sex in our study.