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Effects of Training Load on Sleep Characteristics, Hormonal, and Immune Responses of Adolescent Female Water Polo
Isidora Krimizi1, Argyris Toubekis1,2, Panagiota Klentrou3
1School of Physical Education and Sports Science, National and Kapodistrian University of Athens, Athens,Greece.
Purpose:
To compare the sleep behavior, cortisol, and immunoglobulin A responses between 2 conditions; an experimental condition consisting of 2 consecutive weeks of school and training commitments with low- and high-load training and a 3-day control condition without school and training obligations.
Methods:
Objective sleep characteristics were monitored using ActiGraphy in 11 female water polo athletes (age: 12.9 [1.2] y) during both conditions. In the experimental condition, a low-load training week was followed by a high-load training week. Salivary cortisol and immunoglobulin-A were measured before training.
Results:
Sleep duration was lower and awakenings were fewer in experimental condition compared to control condition (duration: 464.1 [20.6] vs 501.3 [85.0] min, P = .02, d = 0.66; awakenings: 17.4 [8.4] vs 21.1 [10.2], P = .02, d = 0.71). Sleep characteristics were similar between training conditions; however, variability in time in bed and total sleep time was lower during high- (12.34% [6.46%] and 13.32% [7.59%]) than low-load training (16.30% [7.43%] and 17.32% [5.50%]) (P < .01, d = 1.12 and P = .04, d = 0.70). Salivary cortisol and immunoglobulin-A levels were higher during high-load than low-load training (P < .01, d = 1.02 and P < .01, d = 1.38).
Conclusions:
School and sports training commitments reduce sleep duration but improve sleep quality in adolescent water polo athletes, while high-load training reduces sleep variability and increases allostatic load without altering sleep characteristics.
