Decreasing population blood pressure is not mediated by changes in habitual physical activity. Results from 15 years of follow-up

Objective. Population blood pressure (PBP) is the average BP shared by all members of a population. In PBP research, the main focus is on the great majority of individuals who are healthy in respect to blood pressure. From previous studies, we know that PBP decreased 2 mmHg during 15 years of follow-up. This decrease leads to significant reductions in cardiovascular ( CV) and cerebrovascular risk. The major aim of the present study was to evaluate the effect of habitual physical activity on PBP. Design. Copenhagen City Heart Study is a longitudinal epidemiological study of CV risk in a random population sample. Three surveys were performed with 15 years of follow-up. Methods. BP was measured under standardized circumstances. A questionnaire concerning physical exercise was completed. Two scales were used, describing physical activity at work and during leisure-time, respectively. Results. Most of the subjects belonged to the sedentary or low physical activity categories. The population did not change physical activity habits during the observation time. There was no significant difference in either systolic or diastolic BP between the categories. Conclusions. The previously observed reduction in PBP is not explained by a change in the population physical activity habits. This fact illustrates the difference between the high-risk strategy and the population strategy. In the first, the preventive strategy identifies hypertensive individuals and offers them antihypertensive medication and lifestyle modulation such as more and regular physical activity to improve blood pressure and lower individual CV and cerebrovascular risk. In contrast, the "population strategy'' seeks to control the determinants of incidence in the population as a whole. This paper demonstrates that physical activity is not a determinant of PBP.