FORT LEONARD WOOD, MO - Rise and shine may not work as well with young military recruits awakened too early.

That’s according to a new study published in the journal Sleep that found that accommodating adolescent sleep patterns significantly improved mental health and performance in the training environment. To test the theory, sleep periods were altered for a group of U.S. Army recruits at Fort Leonard Wood, MO.1

Recruits assigned to one of two training companies were compared in the quasi-experimental study, according to the authors. One group of 183 had a customary sleep regimen from 20:30 to 04:30, while the other group of 209 was allowed a phase-delayed sleep regimen from 23:00 to 07:00. Researchers note that the latter sleep period aligns better with biologically driven sleep-wake patterns of adolescents.

Demographic and psychophysiological measures were collected for all of the trainees, with weekly assessments of subjective fatigue and mood, periodic physical fitness, marksmanship scores and attrition rates from basic training.

Actigraphy was collected on approximately 24% of trainees. Based on actigraphy, trainees on the phase-delayed sleep schedule obtained 31 minutes more of sleep at night than trainees on the customary sleep schedule.

The intervention group - those with the later sleep schedule — also reported less total mood disturbance relative to baseline.

While improvements in marksmanship correlated positively with average nightly sleep during the preceding week when basic marksmanship skills were taught, no differences were noted in physical fitness or attrition rates.

Yet, compared with the intervention group, the control group was 2.3 times more likely to experience occupationally significant fatigue and 5.5 times more likely to report poor sleep quality.

1. Miller NL; Tvaryanas AP; Shattuck LG. Accommodating adolescent sleep-wake patterns: the effects of shifting the timing of sleep on training effectiveness. SLEEP 2012;35(8):1123-1136.