Relationship Between Exercise Heart Rate and Age in Men vs Women

Objective: To analyze a large cohort of patients who underwent exercise testing and also report sex differences in other exercise heart rate (HR) parameters to determine whether separate sex-based equations to predict peak HR are indicated. Patients and Methods: Patients aged 40 to 89 years who performed treadmill exercise tests (Bruce protocol) from September 21, 1993, to December 20, 2010, were included. Patients with cardiovascular disease or taking HR-attenuating drugs were excluded. After analyses on preliminary cohort, peak HR-modifying factors were eliminated to obtain a pure data set. Analysis of variance was used to test difference in HR responses by sex with age adjustment. Results: A total of 37,010 patients (67.3% men) were included in the preliminary cohort. Men had higher peak HR (166 +/- 17 vs 163 +/- 16 beats/min [bpm]; P<.001), HR reserve (90 +/- 19 vs 84 +/- 17 bpm; P<.001), and HR recovery (19 +/- 8 vs 18 +/- 9 bpm; P<.03). Poor exercise capacity, current smoking, diabetes, and obesity had significant peak HR-lowering effects (all P<.001). In a pure cohort of 19,013 patients (51.3% of full cohort) without these factors, regression lines approximated more closely the traditional line of 220 - age. For men, the regression line in our final cohort was peak HR = 220 - 0.95 x age. For women, both slope (0.79 bpm/y) and intercept (210 bpm) were still substantially different from those obtained with the traditional formula. Conclusion: The HR responses to exercise are different in men and women. The HR response of men was close to that obtained with the traditional formula, but peak HR in women had a lower intercept and decreased more slowly with age. A separate formula for peak HR in women appears to be appropriate. (C) 2014 Mayo Foundation for Medical Education and Research