Exercise blood pressure and the risk of incident cardiovascular disease (from the Framingham Heart Study)

Abstract

Exaggerated systolic blood pressure (BP) augmentation with exercise has been associated with impaired endothelial function and cardiovascular risk. However, previous studies were largely restricted to men, did not evaluate diastolic BP, and focused on peak exercise measures, which are influenced by effort and fitness level. The aim of this study was to determine the association of exercise BP responses with risk of incident cardiovascular disease (CVD). BP was assessed during stage 2 of the Bruce protocol and during recovery in 3,045 Framingham Study subjects (mean age 43 years; 53% women). The association between exercise BP and CVD events during 20 years of follow-up was examined using Cox proportional hazards models. In age- and sex-adjusted analyses, exercise systolic and diastolic BP were associated with incident CVD (adjusted hazard ratios [HRs] for top quintile 1.55, 95% confidence interval [CI] 1.18 to 2.04; and 1.77, 95% CI 1.35 to 2.31, respectively, relative to the lower 4 quintiles; p <0.005). After adjustment for BP at rest and conventional risk factors, exercise diastolic BP (HR 1.41, 95% CI 1.01 to 1.95, p = 0.04), but not exercise systolic BP (HR 0.97, 95% CI 0.68 to 1.38, p = 0.86), remained a significant predictor of CVD. Similarly, in recovery responses after exercise, only diastolic BP (HR 1.53, 95% CI 1.08 to 2.18, p = 0.02) predicted incident CVD in multivariable models. In conclusion, in middle-aged adults, diastolic BP during low-intensity exercise and recovery predicted incident CVD. Our findings support the concept that dynamic BP provides incremental information to BP at rest and suggest that exercise diastolic BP may be a better predictor than exercise systolic BP in this age group.

Figure 1. Distribution of Blood Pressures during Exercise

Histograms showing the distribution of systolic and diastolic BP responses (panel A and B, respectively) for men and women at stage 2 of exercise. BP values plotted represent interval midpoints (e.g., 115 mm Hg represents range 110–119 mm Hg).

Figure 2. Distribution of Blood Pressures during Recovery from Exercise

Histograms showing the distribution of systolic and diastolic BP responses (panel A and B, respectively) for men and women at the third minute of recovery following exercise. BP values plotted represent interval midpoints (e.g., 115 mm Hg represents range 110–119 mm Hg).

Figure 3. Kaplan-Meier Plot: Blood Pressure

Kaplan-Meier plot of survival free of cardiovascular events according to the presence of systolic and diastolic BP in excess of the sex-specific 80^th percentile (Panel A and B, respectively), obtained at the midpoint of the second stage of exercise.