Validation of Maximal Heart Rate Prediction Equations Based on Sex and Physical Activity Status

The purpose of the study was to determine if measured maximal heart rate (HR_max) was affected by sex or aerobic training status, and to determine the accuracy of three common clinical age-prediction maximal heart rate regression equations used to predict HR_max: HR_max= 220 - age, HR_max= 226 - age, and HR_max= 208 - (0.7 · age). Fifty-two participants in total, 30 of which were in the active group (15 M, 15 F) and 22 subjects in the sedentary group (9 M, 13 F), within the age range of 18-25 years and with a normal BMI (18.5-24.9 kg·m^-2) underwent a Bruce maximal treadmill exercise protocol. The effect of sex and training status on HR_max was analyzed through a two-way ANOVA, and the effect of sex, aerobic training status, and regression equation on accuracy of the HR_max prediction was assessed with a three-way ANOVA (α=0.05). Overall, males had a higher HR_max than females (198.3 v. 190.4 beats • min^-1, p<.001) and sedentary individuals had higher measured HR_max than active individuals (197.3 v. 191.4 beats • min^-1, p=.002). Furthermore, HR_max= 208 - (0.7 · age)(equation 3) calculated the smallest signed and unsigned residuals from the difference between observed HR_max and predicted HR_max values for the significant main effects of equation (3), equation × sex (females × 3), and equation × activity level (active × 3). Therefore, based on our results, we conclude that HR= 208 - (0.7 · age) has greater accuracy than the other two equations studied for predicting observed values of HR_max in 18-25 year olds.