Altering meal timing to improve cognitive performance during simulated nightshifts

Altering meal timing could improve cognition, alertness, and thus safety during the nightshift. This study investigated the differential impact of consuming a meal, snack, or not eating during the nightshift on cognitive performance (ANZCTR12615001107516). 39 healthy participants (59% male, age mean?SD: 24.5???5.0y) completed a 7-day laboratory study and underwent four simulated nightshifts. Participants were randomly allocated to: Meal at Night (MN; n=?12), Snack at Night (SN; n =?13) or No Eating at Night (NE; n =?14). At 00:30?h, MN consumed a meal and SN consumed a snack (30% and 10% of 24?h energy intake respectively). NE did not eat during the nightshift. Macronutrient intake was constant across conditions. At 20:00?h, 22:30?h, 01:30?h, and 04:00?h, participants completed the 3-min Psychomotor Vigilance Task (PVT-B), 40-min driving simulator, post-drive PVT-B, subjective sleepiness scale, 2-choice Reaction Time task, and Running Memory task. Objective sleep was recorded for each of the day sleeps using Actigraphy and for the third day sleep, Polysomnography was used. Performance was compared between conditions using mixed model analyses. Significant two-way interactions were found. At 04:00?h, SN displayed increased time spent in the safe zone (p ?355?ms; p