Objectives: Heart rate (HR) has been associated with cardiovascular (CV) risk factors and with CV mortality. Trends in CV risk factors have been described in recent decades, but HR changes over time have been less studied. We thus aimed to examine the secular trends in HR and interrelationships between HR and traditional CV risk factors and mortality.
Methods: We studied 226,288 consecutive participants (141,533 men and 84,755 women) aged 44.7 ± 12.7 years who had a free standard health check up, between 1992 and 2007. Each had resting HR measured systematically on a 10-cycle electrocardiogram, and assessment of lipoproteins, blood pressure, smoking, glycemic status, body mass index, and physical activity. Sex-specific trends in mean HR were estimated by a general linear model adjusted for traditional CV risk factors and CV treatment. In that model, year was considered as a continuous variable.
Results: Crude mean HR decreased over the study period (from 68.9 ± 10.4 to 63.7 ± 9.0 beats/min in men; from 72.2 ± 10.3 to 65.2 ± 9.0 beats/min in women; p < 0.001 for both). The amplitude of the HR decrease was similar after full adjustment and across the pre-cited risk factors categories. On multivariate analysis, higher HR (≥ 80 beats/min vs. <60 beats/min) was associated with higher mortality rate over 5 years in men (hazard ratio 2.11, 95% CI 1.79-2.49) and women (hazard ratio 1.58, 95% CI 1.16-2.15).
Conclusion: In this large population-based study of 226,288 middle-aged participants, heart rate declined over 16 years independently of traditional CV risk factors.