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Altering meal timing to improve cognitive performance during simulated nightshifts.

  • Gupta, Charlotte C1
  • Centofanti, Stephanie1, 2
  • Dorrian, Jillian1
  • Coates, Alison1, 3
  • Stepien, Jacqueline M1
  • Kennaway, David4
  • Wittert, Gary5
  • Heilbronn, Leonie5, 6
  • Catcheside, Peter7
  • Noakes, Manny8
  • Coro, Daniel1
  • Chandrakumar, Dilushi1
  • Banks, Siobhan1
  • 1 Behaviour-Brain-Body Research Centre, School of Psychology, Social Work and Social Policy, University of South Australia, Adelaide, Australia. , (Australia)
  • 2 University of South Australia Online, University of South Australia, Adelaide, Australia. , (Australia)
  • 3 Division of Health Sciences, University of South Australia, Adelaide, Australia. , (Australia)
  • 4 Robinson Research Institute and Adelaide School of Medicine, University of Adelaide, Adelaide, Australia. , (Australia)
  • 5 Discipline of Medicine, Adelaide Medical School, University of Adelaide, Adelaide, Australia. , (Australia)
  • 6 South Australia Medical Research Institute (SAHMRI), Adelaide, Australia. , (Australia)
  • 7 Adelaide Institute for Sleep Health, College of Medicine and Public Health, Flinders University, Adelaide Australia. , (Australia)
  • 8 Food and Nutrition Flagship, Commonwealth Scientific and Industrial Research Organization, Adelaide, Australia. , (Australia)
Published Article
Chronobiology International
Informa UK (Taylor & Francis)
Publication Date
Dec 01, 2019
DOI: 10.1080/07420528.2019.1676256
PMID: 31599661


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 < .001; percentage of time spent within 10 km/h of the speed limit and 0.8 m of lane center), and decreases in speed variability (p < .001), lane variability (p < .001), post-drive PVT-B lapses (defined as RT > 355 ms; p < .001), and reaction time on the 2-choice reaction time task (p < .001) and running memory task (p < .001) compared to MN and NE. MN reported greater subjective sleepiness at 04:00 h (p < .001) compared to SN and NE. There was no difference in objective sleep between eating conditions. Eating a large meal during the nightshift impairs cognitive performance and sleepiness above the effects of time of night alone. For improved performance, shiftworkers should opt for a snack at night.

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