Title

Exercise blood pressure, cardiorespiratory fitness and mortality risk

Document Type

Journal Article

Publication Date

1-1-2021

Journal

Progress in Cardiovascular Diseases

DOI

10.1016/j.pcad.2021.01.003

Keywords

Blood pressure; Cardiorespiratory fitness; Exercise; Hypertension

Abstract

© 2021 Objective: To assess the cardiorespiratory fitness (CRF) impact on the association between exercise blood pressure (BP) and mortality risk. Patients and methods: We assessed CRF in 15,004 US Veterans (mean age 57.5 ± 11.2 years) who completed a standardized treadmill test between January 1, 1988 and July 28, 2017 and had no evidence of ischemia. They were classified as Unfit or Fit according to the age-specific metabolic equivalents (METs) achieved <50% (6.2 ± 1.6 METs; n = 8440) or ≥ 50% (10.5 ± 2.4 METs; n = 6264). To account for the impact of resting systolic BP (SBP) on outcomes, we calculated the difference (Peak SBP-Resting SBP) and termed it SBP-Reserve. We noted a significant increase in mortality associated with SBP-Reserve ≤52 mmHg and stratified the cohort accordingly (SBP-Reserve ≤52 mmHg and > 52 mmHg). We applied multivariable Cox models to estimate hazard ratios (HR) and 95% confidence interval (CIs) for outcomes. Results: Mortality risk was significantly elevated only in Unfit individuals with SBP-Reserve ≤52 mmHg compared to those with SBP-Reserve >52 mmHg (HR = 1.35; CI: 1.24–1.46; P < 0.001). We then assessed the CRF and SBP-Reserve interaction on mortality risk with Fit individuals with SBP-Reserve >52 mmHg serving as the referent. Mortality risk was 92% higher (HR = 1.92%; 95% CI: 1.77–2.09; P < 0.001) in Unfit individuals with SBP-Reserve ≤52 mmHg and 47% higher (HR = 1.47; 95% CI: 1.33–1.62; P < 0.001) in those with SBP-Reserve >52 mmHg. Conclusion: Low CRF was associated with increased mortality risk regardless of peak exercise SBP. The risk was substantially higher in individuals unable to augment their exercise SBP >52 mmHg beyond resting levels.

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