The Association of Resting Heart Rate and Incident Hypertension: The Henry Ford Hospital Exercise Testing (FIT) Project

Abstract

Background: Given that sympathetic tone is associated with hypertension, we sought to determine whether resting heart rate (RHR), as a surrogate for cardiac autonomic function, was associated with incident hypertension.

Methods: We analyzed 21,873 individuals without a history of hypertension who underwent a clinically indicated exercise stress test. Baseline RHR was assessed prior to testing and was categorized as <70, 70-85, and >85 beats-per-minute (bpm). Incident hypertension was defined by subsequent diagnosis codes for new-onset hypertension from three or more encounters. We tested for effect modification by age (<60 vs. ≥60 years), sex, race, and history of coronary heart disease (CHD).

Results: Mean (±SD) age was 49 (±12) years, 55% were men and 21% were Black. Compared to the lowest RHR (<70 bpm) category, patients in the highest category (>85 bpm) were younger, more likely to be female, heavier, diabetic, and achieve lower metabolic equivalents (METS). Over a median of 4 years follow-up, there were 8,179 cases of incident hypertension. Compared to RHR <70 bpm, persons with RHR >85 bpm had increased risk of hypertension after adjustment for CHD risk factors, baseline blood pressure (BP), and METS (hazard ratio = 1.15 (95% confidence interval 1.08-1.23)). Age was an effect modifier (interaction P = 0.02), whereas sex, race, and CHD were not. In age-stratified analyses the relationship remained significant only in those younger than 60 years.

Conclusion: Elevated RHR is an independent risk factor for incident hypertension, particularly in younger persons. Whether lifestyle modification or other strategies to reduce RHR can prevent incident hypertension in high-risk individuals warrants further study.

Keywords: blood pressure; fitness; hypertension; resting heart rate..