Extensive training in elite athletes requires adequate recovery in order to increase performance or performance potential, and to avoid overtraining or other health problems. Heart rate variability (HRV) has been said to reflect the state in the autonomic nervous system and to provide essential information of the parasympathetic regulation, which is significant for post-exercise recovery. HRV has been widely investigated during and after exercise in daytime and after exercise at night, with conflicting results. Therefore, the aim of this study was to investigate the nocturnal cardiac autonomic recovery after one high-intensity interval training session (HIIT) and one long-slow duration training session (LSD), with approximately equivalent training impulse (TRIMP). We hypothesized a greater impact on HRV after the HIIT session and more rapid recovery after the LSD session. Methods: 4 well-trained endurance athletes` nocturnal HRV was monitored during a 7-day protocol: after two non-training days, and for two nights after HIIT and LSD training sessions. Recommendations of Brandenberger et al. (2005) were followed in order to isolate a 5-minute sequence during the first slow wave sleep for further HRV analysis. HRV data for frequency analyzes were processed by Kubios HRV software. TRIMP was calculated prior to exercise according to Foster et al. (2001). Also, TRIMP was calculated after the sessions according to the actual %HRmax during both training sessions. Athletes` life satisfaction was investigated using the Quality of Life Index questionnaire in order to consider the non-training stressors influencing the HRV. Results: No significant effect in the nocturnal cardiac autonomic recovery was found between rest and training, or between the training sessions. Also, no significant change in the non-training stressors was found. Discussion: HIIT or LSD sessions did not introduce significant effects on cardiac autonomic recovery when the non-training stressors remain unchanged. Therefore, the results do not support the hypothesis that a HIIT session would cause greater changes in HRV compared to a LSD session. Also, the hypothesis regarding
© Copyright 2012 17th Annual Congress of the European College of Sport Science (ECSS), Bruges, 4. -7. July 2012. Veröffentlicht von Vrije Universiteit Brussel. Alle Rechte vorbehalten.