TY - JOUR
T1 - Cognitive Impairments during the Transition to Working at Night and on Subsequent Night Shifts
AU - McHill, Andrew W.
AU - Wright, Kenneth P.
N1 - Funding Information:
A.W.M. reports speaker honorarium or travel reimbursement fees from the Utah Sleep Research Society and the California Precast Concrete Association; K.P.W. received funding from the NIH, Office of Naval Research, Philips Inc., Torvec Inc; consulting fees from or served as a paid member of scientific advisory boards for NIH, CurAegis Inc. Circadian Therapeutics, Kellogg; and speaker honorarium or travel reimbursement fees from the American Academy of Sleep Medicine, American College of CHEST Physicians, American College of Sports Medicine, American Diabetes Association, Associated Professional Sleep Societies, Daylight Academy, Illuminating Engineering Society, and the Sleep Research Society.
Funding Information:
The authors would like to thank the participants, Clinical Translational Research Center staff, and Sleep and Chronobiology Laboratory staff as well as T. Moehlman, E. Stothard, B. Birks, B. Smith, B. Brainard, B. Griffin, T. Dear, E. Chinoy, and G. Wright for study assistance. This work was supported by the National Institutes of Health grants R21 DK092624 (K.P.W.), R01 HL109706 (K.P.W.), KL2 TR002370 (A.W.M.), F32 DK107146 (A.W.M.), and T32 HL007901 (A.W.M.), National Institutes of Health (NIH)/National Center for Advancing Translational Sciences Colorado Clinical and Translational Science Award grant UL1 TR002535. Contents are the authors’ sole responsibility and do not necessarily represent official NIH views. These funding sources had no involvement in study design, collection, analysis, interpretation, writing of study results, or decision to submit for publication.
Publisher Copyright:
© 2019 The Author(s).
PY - 2019/8/1
Y1 - 2019/8/1
N2 - Demands of modern society force many work operations into the night when the internal circadian timekeeping system is promoting sleep. The combination of disturbed daytime sleep and circadian misalignment, which is common in overnight shift work, decreases cognitive performance, yet how performance may differ across multiple consecutive nights of shift work is not fully understood. Therefore, the primary aim of this study was to use a simulated night-shift protocol to examine the cognitive performance and ratings of sleepiness and clear-headedness across the hours of a typical daytime shift, a first night shift with an afternoon nap and extended wakefulness, and 2 subsequent overnight shifts. We tested the hypothesis that cognitive performance would be worse on the first night shift as compared with the baseline and subsequent nighttime shifts and that performance during nighttime shifts would be reduced as compared with the baseline daytime shift. Fifteen healthy adults (6 men) were studied in the 6-day in-laboratory protocol. Results showed that working during the night increased subjective sleepiness and decreased clear-headedness and performance on the Psychomotor Vigilance Task (i.e., slower median, fastest and slowest reaction times, and increased attentional lapses), Stroop color word task (decreased number of correct responses and slower median reaction time), and calculation addition performance task (decreased number attempted and correct). Furthermore, we observed limited evidence of sleepiness, clear-headedness, or performance adaptation across subsequent nights of simulated night work. Our findings demonstrate that night-shift work, regardless of whether it is the first night shift with a nap and extended wakefulness or subsequent night shifts, decreases performance and clear-headedness as compared with the day shift.
AB - Demands of modern society force many work operations into the night when the internal circadian timekeeping system is promoting sleep. The combination of disturbed daytime sleep and circadian misalignment, which is common in overnight shift work, decreases cognitive performance, yet how performance may differ across multiple consecutive nights of shift work is not fully understood. Therefore, the primary aim of this study was to use a simulated night-shift protocol to examine the cognitive performance and ratings of sleepiness and clear-headedness across the hours of a typical daytime shift, a first night shift with an afternoon nap and extended wakefulness, and 2 subsequent overnight shifts. We tested the hypothesis that cognitive performance would be worse on the first night shift as compared with the baseline and subsequent nighttime shifts and that performance during nighttime shifts would be reduced as compared with the baseline daytime shift. Fifteen healthy adults (6 men) were studied in the 6-day in-laboratory protocol. Results showed that working during the night increased subjective sleepiness and decreased clear-headedness and performance on the Psychomotor Vigilance Task (i.e., slower median, fastest and slowest reaction times, and increased attentional lapses), Stroop color word task (decreased number of correct responses and slower median reaction time), and calculation addition performance task (decreased number attempted and correct). Furthermore, we observed limited evidence of sleepiness, clear-headedness, or performance adaptation across subsequent nights of simulated night work. Our findings demonstrate that night-shift work, regardless of whether it is the first night shift with a nap and extended wakefulness or subsequent night shifts, decreases performance and clear-headedness as compared with the day shift.
KW - circadian misalignment
KW - mood
KW - performance
KW - sleep deprivation
KW - sleepiness
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U2 - 10.1177/0748730419848552
DO - 10.1177/0748730419848552
M3 - Article
C2 - 31072264
AN - SCOPUS:85065697320
VL - 34
SP - 432
EP - 446
JO - Journal of Biological Rhythms
JF - Journal of Biological Rhythms
SN - 0748-7304
IS - 4
ER -