Elsevier

Progress in Cardiovascular Diseases

Volume 67, July–August 2021, Pages 11-17
Progress in Cardiovascular Diseases

Exercise blood pressure, cardiorespiratory fitness and mortality risk

https://doi.org/10.1016/j.pcad.2021.01.003Get rights and content

Abstract

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.

Section snippets

Alphabetical List of Abbreviations

BMIBody Mass Index
BPBlood Pressure
CADCoronary artery disease
CHFChronic Heart Failure
CIConfidence Interval
CPRSComputerized Patient Record System
CRFCardiorespiratory Fitness
CVDCardiovascular Disease
DM2Type 2 diabetes mellitus
ETHOSExercise Testing and Health Outcomes Study
ETTExercise Treadmill Test
HRHazard Ratio
METsMetabolic Equivalents
PAPhysical activity
PPPulse Pressure
PPIPulse Pressure Index
SBPSystolic Blood Pressure
VETSVeterans Exercise Testing Study

Design and sampling

This prospective cohort study included individuals from a larger dataset, the Exercise Testing and Health Outcomes Study (ETHOS) based at the Veterans Affairs Medical Center, Washington, DC and the Veterans Exercise Testing Study (VETS) based at VA Palo Alto Health Care System. The combined cohort included 21,474 Veterans who had completed a maximal exercise treadmill test (ETT) at the two sites between January 1988 and July 2017 and exhibited no evidence of ischemia (symptoms or

Baseline characteristics and follow-up data

The mean age at the time of the exercise test for the entire cohort (n = 15,004) was 57.5 ± 11.2 years. The mean follow-up time was 13.7 ± 6.8 years, with a median of 13.8 years, comprising a total of 206,683 person-years. There were 4532 deaths (30.2%) with an average annual incidence rate of 21.92 events per 1000 person-years. There was a significant interaction between SBP-Reserve, peak METs (P = 0.01) and CRF categories (P = 0.03). There were no interactions between site and CRF (P = 0.40)

Discussion

The findings of the current study support two clinically significant concepts. First, failure to augment peak exercise SBP by >52 mmHg above resting SBP (SBP-Reserve) was associated with a significantly higher risk of all-cause mortality. Second, this risk was modulated considerably by CRF status. Specifically, when the association between mortality risk and SBP-Reserve was assessed within CRF categories, Fit individuals with SBP-Reserve ≤52 mmHg exhibited no increase in risk. Among Unfit

Study strengths and limitations

Our study has several notable limitations. First, the association between mortality risk, CRF and SBP-Reserve at peak exercise, while compelling, does not demonstrate cause. Second, we do not have data on physical activity (PA) patterns throughout the follow-up; PA patterns not only influence CRF level but may have a direct effect on mortality. Third, the onset of other chronic conditions, their severity, and duration of therapy were not evaluated. The use of 2 different exercise protocols used

Conclusions and clinical relevance

The current findings suggest that the inability to augment SBP in response to exercise >52 mmHg beyond resting levels (SBP-Reserve), was associated with higher mortality in unfit individuals defined as those with peak MET levels ≤6.2. There was no elevated risk regardless of the SBP response among fit individuals (peak METs >6.2; mean 10.2 ± 2.5). There was no elevated risk regardless of the SBP response among fit individuals (peak METs >6.2; mean 10.2 ± 2.5). Therefore, when assessing risk

Sources of funding

None.

Declaration of Competing Interest

None.

Acknowledgment

No conflicts of interest for any of the authors.

References (38)

  • J.A. Dominitz et al.

    Assessment of vital status in Department of Veterans Affairs national databases. Comparison with state death certificates

    Ann Epidemiol

    (2001)
  • P. Kokkinos et al.

    Cardiorespiratory fitness and health outcomes: a call to standardize fitness categories

    Mayo Clin Proc

    (2018)
  • M.G. Schultz et al.

    Blood pressure response to exercise and cardiovascular disease

    Curr Hypertens Rep

    (2017)
  • J.S. Gottdiener et al.

    Left ventricular hypertrophy in men with normal blood pressure: relation to exaggerated blood pressure response to exercise

    Ann Intern Med

    (1990)
  • J. Polonia et al.

    Higher left ventricle mass in normotensives with exaggerated blood pressure responses to exercise associated with higher ambulatory blood pressure load and sympathetic activity

    Eur Heart J

    (1992)
  • J.P. Singh et al.

    Blood pressure response during treadmill testing as a risk factor for new-onset hypertension. The Framingham heart study

    Circulation

    (1999)
  • P. Kokkinos

    Cardiorespiratory fitness, exercise, and blood pressure

    Hypertension

    (2014)
  • K. Hedman et al.

    Workload-indexed blood pressure response is superior to peak systolic blood pressure in predicting all-cause mortality

    Eur J Prev Cardiol

    (2020)
  • K. Currie et al.

    Exercise blood pressure guidelines: time to re-evaluate what is Normal and exaggerated?

    Sports Med

    (2018)
    • View full text
    © 2021 Published by Elsevier Inc.