The influence of vigorous physical exertion on cardiac demand under conditions of daily living among firefighters with elevated blood pressure

Christina A Day; Rachel S Berkowsky; Amanda L Zaleski; Ming-Hui Chen; Beth A Taylor; Yin Wu; Paul M Parducci; Yiming Zhang; Bo Fernhall; Antonio B Fernandez; Linda S Pescatello

doi:10.1016/j.hrtlng.2024.07.008

The influence of vigorous physical exertion on cardiac demand under conditions of daily living among firefighters with elevated blood pressure

Heart Lung. 2024 Nov-Dec:68:208-216. doi: 10.1016/j.hrtlng.2024.07.008. Epub 2024 Jul 23.

Authors

Affiliations

¹ Department of Kinesiology, University of Connecticut, Storrs, CT 06268, USA.
² Department of Kinesiology, University of Connecticut, Storrs, CT 06268, USA. Electronic address: Rachel.berkowsky@uconn.edu.
³ Department of Kinesiology, University of Connecticut, Storrs, CT 06268, USA; Department of Preventive Cardiology, Hartford Hospital, Hartford, CT 06102, USA.
⁴ Department of Statistics, University of Connecticut, Storrs, CT 06268, USA.
⁵ Department of Exercise and Health Sciences, University of Massachusetts, Boston, MA 02125, USA.
⁶ Department of Preventive Cardiology, Hartford Hospital, Hartford, CT 06102, USA.

PMID: 39047646
DOI: 10.1016/j.hrtlng.2024.07.008

Abstract

Background: Firefighters have a high prevalence of cardiovascular disease. The poor heart health of firefighters is implicated in their increased risk of sudden cardiac death (SCD). Exercise may be protective against SCD partially due to the immediate blood pressure (BP) reductions of 5-8 mmHg following exercise, termed postexercise hypotension (PEH) OBJECTIVES: To examine PEH under ambulatory conditions after a maximal cardiopulmonary exercise test (CPET) among career firefighters METHODS: Firefighters (n = 19) completed a maximal CPET and non-exercise control (CONTROL) in random order on separate non-workdays and left the laboratory instrumented to an ambulatory BP (ABP) monitor. Ambulatory systolic BP (ASBP), diastolic BP (ADBP), and heart rate (AHR) were recorded at hourly intervals over 19hr. The ambulatory rate pressure product (ARPP) was calculated as ASBPxAHRx10^-3 at each hourly interval. Repeated measures ANCOVA tested if the ABP, AHR, and ARPP responses differed after CPET vs CONTROL over 19hr RESULTS: Firefighters were middle-aged (39.5 ± 8.9 yr), overweight (29.2 ± 4.0 kg/m²) men with elevated BP (123.1 ± 9.6/79.8 ± 10.4 mmHg), while resting HR (67.7 ± 11.3 bpm) and RPP (8.4 ± 1.7mmHg*bpm*10^-3) were in normal ranges. ASBP (16.6 ± 5.7 mmHg) and ADBP (3.1 ± 4.6 mmHg) increased after the CPET vs CONTROL over 19hr (ps<0.01), as did AHR (9.4 ± 7.9 bpm, p = 0.02) and ARPP (2.5 ± 1.1mmHg*bpm*10^-3, p < 0.01).

Conclusions: Unexpectedly, the firefighters exhibited postexercise hypertension rather than PEH. The increases in ABP and AHR we observed indicated a sustained increase in cardiac demand. Further investigation is needed to confirm our findings and determine whether the adverse hemodynamic responses we observed contribute to the high prevalence of SCD that firefighters experience on the job.

Keywords: Cardiovascular diseases; Exercise; Hypertension; Rate pressure product.

MeSH terms

Adult
Blood Pressure Monitoring, Ambulatory / methods
Blood Pressure* / physiology
Death, Sudden, Cardiac / epidemiology
Death, Sudden, Cardiac / etiology
Death, Sudden, Cardiac / prevention & control
Exercise Test* / methods
Female
Firefighters* / statistics & numerical data
Heart Rate / physiology
Humans
Hypertension* / epidemiology
Hypertension* / physiopathology
Male
Middle Aged
Physical Exertion* / physiology