[Development and evaluation of a new target heart rate formula for the adequate exercise training level in healthy subjects].

Little data is available recommending the adequate exercise level for physical fitness, so we hypothesized that the anaerobic threshold (AT) point is an ideal exercise level. We aimed to determine a new target heart rate formula for the adequate exercise training level in healthy subjects. This study first developed a new formula in 405 subjects (221 males, 184 females, mean age 48.9 +/- 12.3 years). The AT was determined during cycle ergometer exercise with continuous respiratory gas measurements. The correlation of heart rate at the AT to resting heart rate, age and gender was analyzed by the multiple regression method. Based on this correlation, a new formula calculating target heart rate was established as 74.8 + 0.76 x (resting heart rate) - 0.27 x (age) + 7.3 x S (male: 0 or female: 1). This formula was then compared to Blackburn's method in 210 subjects (139 males, 71 females, mean age 44.5 +/- 14.4 years). The difference between the new target heart rate and the heart rate at the AT was significantly lower than that between the target heart rate by Blackburn's method [(220 - age) x 0.7] and the heart rate at the AT (8.8 +/- 6.3 vs 12.7 +/- 8.2 beat/min, p < 0.001). The resting heart rate and gender are important factors in determining the target heart rate for exercise. This new formula indicates the adequate exercise training level more accurately in healthy subjects.