A new method for detecting anaerobic threshold from heart rate recording

The authors detect the anerobic threshold (AT) only from heart rate (HR) recording. Ten subjects performed 13-min cycle exercise on an electrically braked ergometer. The work rate (WR) varied between 40-100 by a pseudorandom binary sequence (dt=1 s, 8 bits, 3 cycles), while HR (beats/min) was calculated every second from R-R intervals. Frequency analysis revealed that the transferred gains from WR to HR at the frequencies of 0.1, 0.2, and 0.3 Hz were less attenuated for all subjects comparing to those of the other frequencies. Therefore, each subject performed incremental exercise (mean Delta =0.33 W/s) with the compounded sinusoidal fluctuation. From this study, it is concluded that AT can be determined only from HR recording. As HR is one of the easiest parameters to measure, especially during exercise, evaluation of AT would therefore be easier by this method.<>