Elevated resting heart rate is associated with several cardiovascular disease risk factors in urban-dwelling black South Africans

N Peer,K Steyn,N Levitt,C Lombard

doi:10.1038/s41598-020-61502-4

Abstract

This study determined the associations of resting heart rate (RHR) with cardiovascular disease risk factors (CVDRF) in 25–74-year-old black South Africans. This cross-sectional study determined CVDRF by administered questionnaires, clinical measurements and biochemical analyses, including oral glucose tolerance tests. Multivariable linear regression models determined the associations of rising RHR with CVDRF. The basic model comprised age, gender, urbanisation, problematic alcohol use, daily cigarette smoking, physical activity and waist circumference. Glucose, blood pressure and cholesterol variables were entered separately and individually in the above model. Among the 1054 participants (382 men and 672 women, mean age 42.8 years), mean RHR was 70.6 beats per minute (bpm) and significantly higher in women (73.6 bpm) compared with men (65.3 bpm). RHR peaked in 45–54-year-old men (69.3 bpm) and 25–34-year-old women (75.3 bpm). Prevalence of RHR < 60 bpm and ≥90 bpm was 24.3% and 6.2%. In the regression model, female gender, problematic alcohol use, decreasing physical activity and increasing waist circumference were significantly associated with rising RHR. All glycaemic variables (diabetes, fasting glucose and 2-hour glucose) and diastolic blood pressure were significantly associated with RHR. The use of RHR in daily primary healthcare settings to identify increased risk for CVDRF should perhaps be encouraged.

Highlights

The mechanism whereby elevated resting heart rate (RHR) wields its harmful effect remains unidentified, several plausible biological mechanisms have been postulated[2]
Elevated RHR has been found to be associated with incident CVD risk factors such as impaired glucose metabolism and type 2 diabetes mellitus, obesity, raised blood pressure (BP) and hypertension, dyslipidaemia, smoking, and physical activity levels[2,7,8,9]
While the mean RHR was 70.6 bpm (SD ± 12.4) overall, it was significantly higher in women (73.6 ± 11.3) compared with men (65.3 ± 12.4) (p < 0.001) (Fig. 1); the gap was wide in 25–34-year-olds at 75.3 bpm in women and 61.1 bpm in men

Summary

Introduction

The mechanism whereby elevated RHR wields its harmful effect remains unidentified, several plausible biological mechanisms have been postulated[2]. Elevated RHR is associated with raised metabolic activity and increased systemic inflammation and is present in the common final pathway of many systemic conditions which involve inflammatory, metabolic, and neurology processes[5]. Elevated RHR has been found to be associated with incident CVD risk factors such as impaired glucose metabolism and type 2 diabetes mellitus (referred to hereafter as diabetes), obesity, raised blood pressure (BP) and hypertension, dyslipidaemia, smoking, and physical activity levels[2,7,8,9]. To our knowledge, these associations have not been established in populations living in Africa; RHR is an overlooked risk factor for CVD4. The aim of this study was to determine the CVD risk factors associated with elevated RHR in 25–74-year-old black residents in Cape Town, South Africa

Objectives

Methods

Results

Conclusion