ABSTRACT

　Aerobic exercise is an excellent way to maintain good health, and marathons are a popular form of aerobic exercise. It has been suggested the appropriate level of exercise intensity should be evaluated to ensure that athletes newly adopting the sport do not harm themselves. Studies that using spectral analysis of heart rate variability （HRV） to evaluate autonomic nervous activity have established HRV as an indicator of exercise intensity. HRV is analyzed in terms of four distinct frequency bands of spectral power: ultra low （ULF）， very low （VF）， low （LF）， and high （HF） frequencies. Evidence suggests that the HF band reflects parasympathetic activity and the LF band reflects sympathetic activity. Thus, the LF/HF ratio reflects sympathovagal balance.This study evaluated two male pacesetter marathon runners wearing ECG leads monitored during a 30-km marathon in Japan. Time series data of the runners’ R-R intervals over 90 min was analyzed with a method of time series analysis based on maximum entropy method. The result obtained showed that the spectral power values in ULF and VLF bands exceeded those in LF and HF bands. Others have reported that ULF and VLF power values decrease as cardiovascular disease severity increases. Accordingly, these values all have clinical prognostic potential for the evaluation of individuals' capacity for exercise.

DECENTE SPORTS SCIENCE Vol.41/The DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE