Can you snooze your way to an 'A'? Exploring the complex relationship between sleep, autonomic activity, wellbeing...

Medical training brings with it multiple stressors, including demanding workloads in highly competitive environments, with well-documented impact on psychiatric morbidity. This study evaluated the impact of sleep-related factors on psychological wellbeing, cognitive task performance and academic standing in medical students.

A total of 59 undergraduate medical students took part in this cross-sectional study over two consecutive days. Participants responded to questionnaires about their physical and psychological health, sleep, functioning and academic performance at the initial visit. Participants then wore an ambulatory bioharness overnight (to derive heart rate variability measures), before returning to complete a computerised battery of cognitive tasks. A sleep diary was completed for the next 7 days.

Poor sleep quality in the month preceding assessment correlated with psychological distress ( p < 0.001) and reduced nocturnal heart rate variability ( p = 0.007). Psychological distress also correlated with reduced nocturnal heart rate variability ( p = 0.031) and less refreshing sleep during the monitoring week ( p < 0.001), but not with sleep timing parameters. A greater increase in heart rate variability during the transition from awake to sleep significantly predicted better spontaneous cognitive performance ( p = 0.021). Better academic standing was predicted by consistently short, less refreshing sleep (all p < 0.001), along with earlier bedtimes ( p = 0.004) and greater psychological wellbeing ( p = 0.009).

Unrefreshing, short-duration sleep and psychological distress are prevalent in medical students during university training and were associated with reduced nocturnal parasympathetic autonomic activity. Achieving higher academic grades was associated with high psychological wellbeing despite consistently short, unrefreshing sleep. The long-term repercussions of such sleep behaviours on later professional functioning remain unclear, warranting further research.