Reducing scheduled evening training does not improve recruits' sleep duration or quality during British Army basic training.

Introduction: Sleep is critical to the health, wellbeing and performance of recruits during Army basic training, however, is often sacrificed due to the constraints of basic training schedules. In an effort to improve sleep duration of recruits, the revised Common Military Syllabus 21 (CMS21) restricted daily scheduled military training from 18:30, thus enabling greater opportunity for earlier bedtimes and longer nocturnal sleep periods. Our objective was to evaluate the effectiveness of the revised CMS21 basic training programme on measures of sleep-wake indices and compare against the previous programme (CMS18) as a control group. Methods: Several actigraphy-derived and self-reported sleep-wake indices assessed potential changes in sleep opportunity between groups (CMS21 vs CMS18) and across 12-weeks of basic training. Actigraphy was measured daily to deduce weekly averages and self-report measures (i.e., sleep diaries) were captured during weeks 1, 6 and 11 of basic training. Sleep-wake data are presented descriptively (mean ± SD) and a series of linear-mixed models determined differences in actigraphy between groups and across each week. Results: Compared to CMS18, no significant improvements in any sleep-wake indices were observed during CMS21. The average sleep duration for both groups remained below the minimum national sleep duration recommendations for young adults (deficit of ~1 h 20 m), with 67% to 94% of recruits in CMS18 and 69% to 97% of recruits in CMS21 achieving an average of <7 h sleep per night, respectively. Similar proportions of recruits reported poor-levels of sleep quality (≤ 60%) during CMS18 and CMS21, with excessive noise and early-morning wake times identified as the most common sleep disturbances. The contracted early-morning feeding times and the magnitude of non-scheduled late-evening military admin were determined as key factors preventing adequate sleep opportunity despite restricting scheduled military training from 18:30 during CMS21. Discussion: The results of this study warrant the application of improved sleep hygiene practices within the basic training environment. It is also recommended that the contracted early-morning feeding times and magnitude of non-scheduled training activity be considered as factors for change within future programme design to optimize sleep opportunity during basic training.