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Published on: June 18, 2014
A 14-Day Sleep Hygiene Intervention Improves Aerobic Performance and Reduces Anticipatory Cortisol in University
Adele Broodryk1, Retief Broodryk1
1Physical Activity, Sport and Recreation Research Focus Area (PhASRec), Faculty of Health Sciences, North-West University, Potchefstroom 2520, South Africa.
Abstract:
Background: Sleep is a critical recovery mechanism for athletes, supporting hormonal regulation, muscle repair, and cognitive function. Dual-career athletes are particularly vulnerable to sleep disruption, which may impair performance and stress regulation. This study examined the effects of a 14-day sleep hygiene intervention protocol (SHIP) on aerobic and anaerobic performance, as well as anticipatory cortisol responses, in university-level soccer players. Methods: Thirty athletes (females: n = 14, 22.1 ± 3.3 y, 157.8 ± 6.0 cm, 53.5 ± 3.9 kg, males: n = 16, 21.5 ± 1.7 y, 167.5 ± 5.9 cm, 62.7 ± 5.4 kg) completed the Pittsburgh Sleep Quality Index (PSQI), provided pre-test salivary cortisol samples, and performed the Yo-Yo Intermittent Recovery Test Level 1 (YYIR1) and Repeated Anaerobic Sprint Test (RAST) before and after the intervention (adhering daily to 10-18 individualized sleep hygiene). Results: The SHIP significantly reduced sleep latency (p = 0.04) and increased sleep duration (p = 0.03), and PSQI scores (p < 0.001) in both sexes. Females showed marked increases in sleep duration (p = 0.002), while males showed improved latency (p = 0.07). Five behaviourally coherent clusters derived from the SHIP adherence explained a substantial proportion of variance (74.99%). Stimulant and metabolic regulation, and bedroom light and thermal environment control consistently predicted sprint and physiological outcomes (p < 0.05). Anticipatory cortisol decreased before both tests (p = 0.03-0.04). YYIR1 performance improved for the full cohort (p = 0.001). RAST times slowed slightly (p = 0.02), though fatigue index improved (p = 0.05). Conclusions: A short-term SHIP effectively enhanced sleep, reduced physiological stress, and improved key performance outcomes in collegiate athletes.
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