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Evaluation of Maximal Heart Rate Prediction Equations for Women During Breast Cancer Treatment: A Measurement Focused Study

Background: Maximal heart rate (HRmax) prediction equations based on age are commonly used for determining exercise test endpoints and training heart rate intensities for exercise prescriptions. The accuracy of currently recommended prediction equations has not been evaluated among women in treatment for breast cancer. Objective: To determine whether predicted HRmax values are similar to HRmax measures from women undergoing breast cancer treatment. Design: The study was a measurement focused design. Methods: Following institutional review board approvals, subjects were recruited from a cancer treatment center. HRmax was measured during symptom‐limited graded exercise tests (GXT) using a 12‐lead electrocardiogram and oxygen uptake analysis among 13 women [49.08 (7.64) years] undergoing breast cancer treatment. Subjects performed two GXTs approximately 8 weeks apart resulting in 26 total tests. Graded exercise tests ended when HR or oxygen uptake plateaued or when respiratory exchange ratios were >1.15. Friedman's (ANOVA) assessed differences between current predication equations [206.9 − (0.67 × age in years)] and [220 − (age in years)] and the actual HRmax measures with significance at P ≤ .05 (two‐tailed). Results: Predicted HRmax values from both equations were significantly higher than measured values by 7 to 10 beats per minute (Chi2 = 45.2; df = 2; P < .001). A subsequent linear mixed models statistical analysis generated a new HRmax prediction equation of [206.7 − (0.86 × age)]; significant for the age intercept (P < .001) and the coefficient (P = .040). Limitations: The small sample and inability to generalize to other cancer diagnoses. Conclusions: Current prediction equations may significantly overestimate actual HRmax measures among women in breast cancer treatment. A significant univariate HRmax prediction equation was generated from study measures. The equation requires further confirmation with larger samples and among individuals with other cancer diagnoses.