The impact of time-updated resting heart rate on cause-specific mortality in a random middle-aged male population: a lifetime follow-up

BACKGROUND: A high resting heart rate (RHR) is associated with an increase in adverse events. However, the long-term prognostic value in a general population is unclear. We aimed to investigate the impact of RHR, based on both baseline and time-updated values, on mortality in a middle-aged male cohort. METHODS: A random population sample of 852 men, all born in 1913, was followed from age 50 until age 98, with repeated examinations including RHR over a period of 48 years. The impact of baseline and time-updated RHR on cause-specific mortality was assessed using Cox proportional hazard models and cubic spline models. RESULTS: A baseline RHR of ≥ 90 beats per minute (bpm) was associated with higher all-cause mortality, as compared with an RHR of 60-70 bpm (hazard ratio [HR] 1.60, 95% confidence interval [CI] 1.17-2.19, P = 0.003), but not with cardiovascular (CV) mortality. A time-updated RHR of < 60 bpm (HR 1.41, 95% CI 1.07-1.85, P = 0.014) and a time-updated RHR of 70-80 bpm (HR 1.34, 95% CI 1.02-1.75, P = 0.036) were both associated with higher CV mortality as compared with an RHR of 60-70 bpm after multivariable adjustment. Analyses using cubic spline models confirmed that the association of time-updated RHR with all-cause and CV mortality complied with a U-shaped curve with 60 bpm as a reference. CONCLUSION: In this middle-aged male cohort, a time-updated RHR of 60-70 bpm was associated with the lowest CV mortality, suggesting that a time-updated RHR could be a useful long-term prognostic index in the general population.