Objective: To study the protective role of lower resting heart rate (RHR) in cardiovascular disease (CVD) and all-cause mortality.
Patients and methods: Patients (n=53,322) who received a baseline medical examination between January 1, 1974, and December 31, 2002, were recruited from the Cooper Clinic, Dallas, Texas. They completed a medical questionnaire and underwent clinical evaluation. Patients with CVD or cancer or who had less than 1 year of mortality follow-up were excluded from the study. Relative risks and 95% CIs for all-cause and CVD mortality across RHR categories were estimated using Cox proportional hazards models.
Results: Highest cardiorespiratory fitness with lower mortality was found in individuals with an RHR of less than 60 beats/min. Similarly, patients with a higher RHR (≥80 beats/min) were at greater risk for CVD and all-cause mortality compared with an RHR of less than 60 beats/min. This analysis was followed by stratification of the data by hypertension, where hypertensive individuals with high RHRs (≥80 beats/min) were found to be at greater risk for CVD and all-cause mortality compared with those with hypertension and lower RHRs (<60 beats/min). In addition, unfit individuals with high RHRs had the greatest risk of CVD and all-cause mortality. The unfit with low RHR group had a similar risk for CVD and all-cause mortality as the fit with high RHR group.
Conclusion: Lower cardiorespiratory fitness levels and higher RHRs are linked to greater CVD and all-cause mortality.
Keywords: ACLS; Aerobics Center Longitudinal Study; BP; CHD; CRF; CV; CVD; HR; HTN; PA; RHR; blood pressure; cardiorespiratory fitness; cardiovascular; cardiovascular disease; coronary heart disease; hazard ratio; hypertension; physical activity; resting heart rate.
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