RT Journal Article
SR Electronic
T1 Scheduled afternoon–evening sleep leads to better night shift performance in older adults
JF Occupational and Environmental Medicine
JO Occup Environ Med
FD BMJ Publishing Group Ltd
SP 179
OP 184
DO 10.1136/oemed-2019-105916
VO 77
IS 3
A1 Cheryl Martine Isherwood
A1 Evan D Chinoy
A1 Audra S Murphy
A1 Jee Hyun Kim
A1 Wei Wang
A1 Jeanne F Duffy
YR 2020
UL http://oem.bmj.com/content/77/3/179.abstract
AB Objectives This study investigated whether an intervention designed to reduce homeostatic sleep pressure would improve night shift performance and alertness in older adults.Methods Non-shift workers aged 57.9±4.6 (mean±SD) worked four day (07:00–15:00) and four night shifts (23:00–07:00). Two intervention groups were instructed to remain awake until ~13:00 after each night shift: the sleep timing group (ST; n=9) was instructed to spend 8 hours in bed attempting sleep, and the sleep ad-lib group (n=9) was given no further sleep instructions. A control group (n=9) from our previous study was not given any sleep instructions. Hourly Karolinska Sleepiness Scales and Psychomotor Vigilance Tasks assessed subjective sleepiness and performance.Results The ST group maintained their day shift sleep durations on night shifts, whereas the control group slept less. The ST group were able to maintain stable performance and alertness across the initial part of the night shift, while the control group’s alertness and performance declined across the entire night. Wake duration before a night shift negatively impacted sustained attention and self-reported sleepiness but not reaction time, whereas sleep duration before a night shift affected reaction time and ability to sustain attention but not self-reported sleepiness.Conclusions A behavioural change under the control of the individual worker, spending 8 hours in bed and waking close to the start of the night shift, allowed participants to acquire more sleep and improved performance on the night shift in older adults. Both sleep duration and timing are important factors for night shift performance and self-reported sleepiness.