The Accuracy of Selected Equations to Predict Maximal Heart Rate in African American Men

Abstract

Strength and conditioning professionals, exercise physiologists, and coaches have long used maximal heart rate (MHR) as an acceptable method for prescribing aerobic exercise intensity. There have been a large number of age-predicted MHR equations developed. However, some age-predicted MHR equations appear to be more accurate for certain individuals, which seems to depend on various factors such as sex, age range, training status, and the mode of exercise used. While there is limited evidence to suggest a racial difference between African-American (AA) individuals and Caucasians in the kinetics of heart rate during and after exercise, the data regarding age-predicted MHR equations specifically for AA subjects is lacking. PURPOSE: The purpose of this investigation was to compare five of the most commonly used MHR prediction equations to actual MHR in young adult AA men. METHODS: Thirty AA men (mean age = 22.1 +/- 2.2 years, range = 19 to 31 years) volunteered to participate in this study. Each subject performed a maximal graded exercise test on a treadmill. Heart rate was measured continuously throughout the exercise test via electrocardiography. Gas exchange was also assessed to determine maximal oxygen consumption (V̇o2max). The heart rate value that corresponded to V̇o2max was recorded as actual MHR (aMHR). MHR was also predicted by using five commonly used age-predicted MHR equations as follows: 1) 220-age (Fox et al. 1971); 2) 208 - [0.7 × age] (Tanaka et al. 2001); 3) 216 - [0.84 × age] (Åstrand, 1952); 4) 205.8 - [0.685 × age] (Inbar et al. 1994); and 5) 206.9 - [0.67 × age] (Gellish et al. 2007). Repeated measures analysis of variance (ANOVA) with an LSD follow-up was used to determine if there were any differences between the aMHR and the five MHR equations (p < 0.05). RESULTS: The mean aMHR for the entire group was 188.5 +/− 4.7 beats/min. Each equation's predicted MHR mean was as follows: Fox et al. = 196.8 +/− 3.2 beats · min−1; Tanaka et al. = 191.7 +/− 3.2 beats · min−1; Åstrand et al. = 196.5 +/− 2.7 beats · min−1; Inbar et al. = 189.9 +/− 2.2 beats · min−1; and Gellish et al. = 191.4 +/− 2.1 beats · min−1. The mean predicted MHR of Fox et al., Tanaka et al., and Åstrand et al. were significantly higher compared to aMHR (p < 0.05). However, there was no difference between the predicted MHR of Inbar et al. and aMHR. CONCLUSIONS: For predicting MHR in young adult AA men, it appears that the MHR prediction equation of Inbar et al. is the most accurate. The other age-predicted MHR equations (i.e., Fox et al., Tanaka et al., Åstrand, Gellish et al.) significantly over-estimated MHR. PRACTICAL APPLICATIONS: It is very common to use MHR for establishing aerobic exercise intensity in the fitness industry. The results of this present investigation suggest that of the MHR prediction equations analyzed in the study, the equation by Inbar et al. (1993) appears to be the most precise for AA men. Currently, there are no MHR equations available that are race-specific. Therefore, future research is warranted to further explore the possibility of developing predicted MHR equations that are specific for AA individuals.