Effects of Nightly Electronic Device Restriction and Morning Bright Light on Sleep, Mood, and Performance Among Elite Athletes

ABSTRACT: Hoshikawa, M. Effects of nightly electronic device restriction and morning bright light on sleep, mood, and performance among elite athletes. J Strength Cond Res 39(11): 1155-1162, 2025-This study aimed to evaluate whether restriction of electronic device use before bedtime and morning bright-light exposure influences sleep, sleepiness, mood, and performance parameters among elite athletes. Twenty-five elite athletes (24 international level and 1 national level) were divided into 2 groups: with (INT; n = 12) and without (CON; n = 13) intervention. The INT turned off their electronic devices 30 minutes before bedtime and were exposed to morning bright light (approximately 10,000 lux) for 20 minutes after waking. Their nocturnal sleep parameters, Karolinska sleepiness scale, subjective sleep quality, fatigue, and heart rate immediately after waking were monitored every morning for 2 weeks. The Epworth sleepiness scale (ESS) score, Profile of Mood States (POMS) vigor and fatigue scores, reaction time, isometric grip strength, squat jump (SJ) height, rebound jump (RJ) height, RJ index, and heart rate during aerobic exercise were evaluated before and after the 2-week period. The RJ index was calculated as RJ height (m)/ground contact time (sec). For the INT, POMS vigor score ( p < 0.001), reaction time ( p = 0.016), RJ height ( p = 0.001), and RJ index ( p < 0.001) improved without any change in sleep parameters. The improvements in ESS score and SJ height seemed to be greater in the INT group, but the interactions did not reach a significant level ( p < 0.10). No statistically significant interaction was observed in the exercise heart rate and isometric grip strength. Two weeks of 30 minutes nighttime electronic device restriction and 20 minutes morning bright-light exposure improved mood and some performance parameters among elite athletes. However, the intervention did not change athletes' sleep parameters.