The aim of this study was to clarify whether the physiological fatigue status of elite speed skaters is influenced by the approximately five-month international competition season by comparing morning heart rate variability (HRV) at the beginning of the competition season (Japan Single Distances Championships: JSDC) with that at the end of the competition season (World Single Distances Championships: WSDC). Five international-class speed skaters participated in the study. HRV indices and subjective fatigue were measured each morning of the four days prior to the first races of the JSDC and WSDC in the 2007/2008 season. The parasympathetic HRV indices: root mean square of the successive R-R interval differences (RMSSD) (JSDC, 61.0 ms; WSDC, 42.1 ms; p < 0.05), high-frequency component power (HF) (JSDC, 1393 ms²; WSDC, 443 ms²; p < 0.05), and normalized unit of HF (HFnu) (JSDC, 53.2%; WSDC, 25.5%; p < 0.05) were lower for the WSDC than for the JSDC. The decrease in these indices may reflect the skaters’ accumulated fatigue during the course of the competition season. Morning measurements of HRV may thus be an efficient way for elite speed skaters and coaches to objectively monitor physiological fatigue throughout the competition season.

中文翻译：

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优秀速滑运动员比赛季节开始和结束时早晨心率变异性的比较

这项研究的目的是通过比较比赛季节开始时的早晨心率变异性（HRV）来阐明精英速滑运动员的生理疲劳状态是否受到大约五个月的国际比赛季节的影响（日本单距离锦标赛： JSDC）与比赛结束时（世界单人距离锦标赛：WSDC）一起使用。五名国际一流的速滑运动员参加了这项研究。在2007/2008赛季的JSDC和WSDC首次比赛前四天的每个早晨，测量HRV指数和主观疲劳。副交感神经的HRV指数：连续RR间隔差的均方根（RMSSD）（JSDC，61.0 ms; WSDC，42.1 ms; p <0.05），高频分量功率（HF）（JSDC，1393 ms）² ; WSDC，443 ms ²；p <0.05）和HF（HFnu）的标准化单位（JSDC，53.2％; WSDC，25.5％; p <0.05）低于JSDC。这些指数的降低可能反映了滑冰运动员在比赛季节中累积的疲劳。因此，HRV的早间测量可能是优秀的速滑运动员和教练在整个比赛赛季中客观监测生理疲劳的有效方法。