A graded association of exercise capacity and all-cause mortality in males with high-normal blood pressure

INTRODUCTION: Information regarding the effect of exercise capacity on mortality risk in individuals with high-normal blood pressure is severely limited. Thus, we evaluated the association of exercise capacity and all-cause mortality in individuals with high-normal blood pressure. METHODS: Exercise test was performed in 1727 males with high-normal blood pressure at two Veteran sites (Washington, DC, and Palo Alto, CA). Fitness status was assessed in metabolic equivalents (METs) at exercise peak. All-cause mortality was recorded for a mean follow-up period of 9.8+/-6.0 years. RESULTS: Exercise capacity was inversely associated with all-cause mortality, and the association was independent of traditional cardiovascular risk factors. For each 1 MET increase in exercise capacity, the adjusted mortality risk was reduced by 13%, underscoring the strong predictive value of exercise capacity that was confirmed by ROC analysis. Data analysis according to fitness levels revealed a threshold level of 4 METs, over which the mortality risk was progressively reduced by 30% (hazard ratio=0.70; CI 0.51-0.95) for those who achieved 4.1-6.0 METs and 61% (hazard ratio=0.39; CI 0.26-0.57) for those who achieved 8.1-10 METs. No additional reductions in risk were noted until the MET level achieved exceeded 12 METs. CONCLUSIONS: We observed a strong, inverse, graded and independent association between exercise capacity and all-cause mortality in individuals with high-normal blood pressure. Our findings indicate that a shift of the fitness curve to the right is associated with significant survival benefits, and even slight differences in fitness levels are associated with substantial reductions in mortality risk.