Sleep/Wake Behaviour Of Competitive Adolescent Athletes In New Zealand: Insight Into The Impact Of Early Morning Training

Objective: Sleep plays a crucial role in the health, wellbeing, and development of adolescent athletes' sporting and academic lives. This study aimed to monitor the sleep/wake behaviour of adolescent athletes who have frequent early morning training sessions.Methods: 13 swimmers (mean age 14.8 +/- 1.4; 46% male) and 19 rowers (mean age 16.5 +/- 1.1; all male) wore actigraphs and completed sleep diaries over a 2-week training period. Diaries included the Hooper Index and a question regarding device use before bed. Participants also completed chronotype questionnaires. Nights of the week were categorised as taking place before "morning training", "mornings off", "weekend mornings off", and "weekend morning training". Actigraphy and sleep diary variables were compared for different nights of the week.Results: All athletes were classified as "morning type". Average sleep duration across the study was 7h55 (+/- 1h33). Median sleep duration was significantly shorter on nights before weekday morning training (6h44) compared to weekday mornings off (8h45). This was due to an earlier wake time (04:51) while bedtime remained constant (similar to 22:15). Athletes went to bed later, woke later and slept for longer on nights before weekend mornings off compared to weekday nights.Conclusions: Early morning training advanced the wake times of the athletes while bedtime remained constant. This shortened sleep below age recommended durations on the nights before early morning training during the week. These findings suggest that weekly average sleep duration does not accurately reflect athletes' nightly sleep given the large variability across a training week. (C) 2020 Elsevier B.V. All rights reserved.