The impact of meal timing on performance, sleepiness, gastric upset, and hunger during simulated night shift

Ind Health. 2017 Oct 7;55(5):423-436. doi: 10.2486/indhealth.2017-0047. Epub 2017 Jul 25.


This study examined the impact of eating during simulated night shift on performance and subjective complaints. Subjects were randomized to eating at night (n=5; 23.2 ± 5.5 y) or not eating at night (n=5; 26.2 ± 6.4 y). All participants were given one sleep opportunity of 8 h (22:00 h-06:00 h) before transitioning to the night shift protocol. During the four days of simulated night shift participants were awake from 16:00 h-10:00 h with a daytime sleep of 6 h (10:00 h-16:00 h). In the simulated night shift protocol, meals were provided at ≈0700 h, 1900 h and 0130 h (eating at night); or ≈0700 h, 0930 h, 1410 h and 1900 h (not eating at night). Subjects completed sleepiness, hunger and gastric complaint scales, a Digit Symbol Substitution Task and a 10-min Psychomotor Vigilance Task. Increased sleepiness and performance impairment was evident in both conditions at 0400 h (p<0.05). Performance impairment at 0400 h was exacerbated when eating at night. Not eating at night was associated with elevated hunger and a small but significant elevation in stomach upset across the night (p<0.026). Eating at night was associated with elevated bloating on night one, which decreased across the protocol. Restricting food intake may limit performance impairments at night. Dietary recommendations to improve night-shift performance must also consider worker comfort.

Keywords: Circadian misalignment; Hunger; Performance; Psychomotor vigilance; Shift-work; Sleep loss; Sleepiness; Timed eating.

MeSH terms

  • Adolescent
  • Adult
  • Circadian Rhythm / physiology*
  • Humans
  • Hunger / physiology*
  • Male
  • Meals*
  • Middle Aged
  • Psychomotor Performance / physiology
  • Shift Work Schedule*
  • Sleep Deprivation
  • Stomach Diseases
  • Task Performance and Analysis