Influence Of Training Load On Heart Rate Variability And Salivary Cortisol In Elite Badminton Players: 2804 Board #119 May 29, 3

In order to make athletes good form for a competition, it is necessary to continuously monitor their physical condition. Recent studies suggest that measuring heart rate variability (HRV) would be efficient to evaluate physical condition. It has not been shown, however, whether HRV indices are influenced by changes in training load toward a competition in elite athletes. PURPOSE: To examine influence of training load on HRV indices as well as salivary cortisol concentration (SCor), salivary immunoglobulin A secretion rate (SIgA) and subjective feeling of fatigue in elite athletes. METHODS: Eleven Japanese badminton national team players (22.5±3.0 yrs) participated in the study. Data were collected during an 8-day badminton national team training camp. As it was immediately followed by a major international competition, the main purpose of the training camp was to make the players in good form for the competition. Training load was quantified by Training Impulse (TRIMPs). Every morning, beat-to-beat heart rate (HR) was recorded for 5 minutes. Spectral analysis was used to calculate spectral power in the high-frequency (HF: 0.15-0.40Hz) band which represents parasympathetic autonomic activity. Saliva samples were collected to measure SCor and SIgA. The subjects were also asked to estimate subjectively perceived fatigue on a visual analogue scale. RESULTS: As training intensity and duration both decreased in the course of the training camp, TRIMPs in the second half (Day5-8) of the training camp significantly decreased from that in the first half (Day1-4) (325.9±71.9 vs. 223.2±47.6 a.u., p<0.01). In response to the decrease in TRIMPs, HF significantly increased whereas HR and SCor significantly decreased from the first to the second half (HF: 1032.5±557.7 vs. 2217.7±1354.4 msec2, p<0.01, HR: 56.8±5.5 vs. 53.2±4.6 beats/min, p<0.01, SCor: 0.50±0.11 vs. 0.43±0.08 ug/dl, p<0.05). In contrast, no significant change was observed in SIgA and subjective feeling of fatigue (SIgA: 140.2±72.1 vs. 122.2±65.6 ug/min, subjective feeling of fatigue: 54.0±12.1 vs. 61.2±15.4 mm). CONCLUSION: HF, HR and SCor would be efficient indices for elite athletes to objectively monitor the influence of training load on physical condition. Supported by The Descente and Ishimoto Memorial Foundation for the Promotion of Sports Science.