Effects of Late-Night Training on “Slow-Wave Sleep Episode” and Hour-by-Hour-Derived Nocturnal Cardiac Autonomic Activity in Female Soccer Players
in International Journal of Sports Physiology and PerformanceClick name to view affiliation
Purpose: To assess the sensitivity of nocturnal heart-rate-variability-monitoring methods to the effects of late-night soccer training sessions in female athletes. Methods: Eleven female soccer players competing in the first division of the Portuguese soccer league wore heart-rate monitors during sleep at night throughout a 1-wk competitive in-season microcycle, after late-night training sessions (n = 3) and rest days (n = 3). Heart rate variability was analyzed through “slow-wave sleep episode” (10-min duration) and “hour by hour” (all the RR intervals recorded throughout the hours of sleep). Training load was quantified by session rating of perceived exertion (281.8 [117.9] to 369.0 [111.7] arbitrary units [a.u.]) and training impulse (77.5 [36.5] to 110.8 [31.6] a.u.), added to subjective well-being ratings (Hopper index = 11.6 [4.4] to 12.8 [3.2] a.u.). These variables were compared between training and rest days using repeated-measures analysis of variance. Results: The log-transformed slow-wave sleep-episode cardiac autonomic activity (lnRMSSD [natural logarithm of the square root of the mean of the sum of the squares of differences between adjacent normal RR intervals] varying between 3.92 [0.57] and 4.20 [0.60] ms;
Costa, Oliveira, and Rebelo are with the Center of Research, Education, Innovation and Intervention in Sport, Faculty of Sport, University of Porto, Porto, Portugal. Brito is with the Portugal Football School, Portuguese Football Federation, Oeiras, Portugal. Nakamura is with the Dept of Medicine and Aging Sciences, “G. d’Annunzio” University of Chieti-Pescara, Chieti, Italy, and the College of Healthcare Sciences, James Cook University, Douglas, QLD, Australia.
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