Night-shift work increases cold pain perception

European Journal of Pain

Knardahl

et al. 2019

Background The increased pain sensitivity following reduced sleep may be related to changes in cortical processing of nociceptive stimuli. Expectations shape pain perception and can inhibit (placebo) or enhance (nocebo) pain. Sleep restriction appears to enhance placebo responses; however, whether sleep restriction also affects nocebo responses remains unknown. The aim of the present study was to determine whether sleep restriction facilitates nocebo‐induced changes in pain and pain‐evoked cortical potentials. Methods In an experimental study with a crossover design, the sensitivity to electrically induced pain was determined in 53 nurses under two sleep conditions, after habitual sleep and after two consecutive nights at work. Nocebo was induced by conditioning one‐third of the pain stimuli. Pain‐elicited cortical event‐related potentials were recorded by electroencephalography (EEG). Data were analysed both in the time domain (N2P2 amplitude) and in the time–frequency domain (ERP magnitude). Sleepiness and vigilance were also assessed. Results Both nocebo alone and sleep restriction alone increased the sensitivity to electrically induced pain. However, no interaction effect was found. Moreover, the magnitude of the pain‐elicited responses increased after sleep restriction and decreased after nocebo expectation, suggesting that nocebo is probably not an underlying mechanism for the commonly observed hyperalgesia induced by sleep restriction. Conclusions The present work addresses whether sleep restriction, known to increase the sensitivity of the pain system, facilitates nocebo‐induced hyperalgesia. Our findings suggest that this is not the case, indicating that the increased sensitivity of the pain system following nocebo and sleep restriction are mediated by different cortical mechanisms.

Section: Discussionsupporting

confidence: 89%

“…After night work, compared to after habitual sleep, subjective pain scores increased by 19% (mean difference 0.4 cm). This effect size was comparable to other studies on heat pain (26.5% increase) based on data from the same individuals (Matre et al, 2017) and another study on cold pain after night work (28% increase) (Pieh et al, 2018) Nilsen, 2016;Matre, Hu, et al, 2015;Schuh-Hofer et al, 2015;Tiede et al, 2010). Subjective pain scores increased by 20% (mean difference 0.30 cm) in the nocebo versus control conditions.…”

Section: Discussionsupporting

confidence: 85%

Sleep restriction does not potentiate nocebo‐induced changes in pain and cortical potentials

Ree

European Journal of Pain

Knardahl

et al. 2019

“…Two other shift-work factors with well-documented impact on health are the number of consecutive night shifts (Jensen et al 2016), and the length of the restitution period between shifts (Vedaa et al 2015). Night shifts disturb the diurnal rhythm (Jensen et al 2016) and has been associated with pain complaints in micro-longitudinal studies (Katsifaraki et al 2018), findings supported by experimental studies (Matre et al 2017;Pieh et al 2018). Quick returns (QRs), defined as < 11 h off between shifts, disturb sleep (Vedaa et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Pain complaints are associated with quick returns and insomnia among Norwegian nurses, but do not differ between shift workers and day only workers

Matre

Int Arch Occup Environ Health

Katsifaraki

et al. 2019

“…In addition, Katsifaraki et al investigated an increase in pain on a Likert-type scale from day to day, whereas in the present study pain was dichotomized each day as no pain or pain. Another study showed increased pain sensitivity the day after a night shift, but this was normalized after a night of normal sleep (35). It is therefore conceivable that there could be an association when examining TST and an increase in pain from day to day, but not when analyzing TST and number of days with pain.…”

Section: Discussionmentioning

confidence: 99%

The association between proportion of night shifts and musculoskeletal pain and headaches in nurses: a cross-sectional study

Stavas¹,

Matre³

2023

Preprint

Objectives: To investigate whether a higher proportion of night shifts is associated with a higher occurrence of musculoskeletal pain and headaches. Furthermore, to investigate whether sleep duration can mediate this potential association. Method: The study included 684 nurses in rotating shift work (day, evening, night) who responded to a daily questionnaire about working hours, sleep, and pain for 28 consecutive days. The data were treated as cross-sectional data. Results: A negative binomial regression analysis adjusted for age and BMI revealed that working a higher proportion of night shifts is not associated with a higher occurrence of musculoskeletal pain and headaches. On the contrary, those working ≥50 % night shifts had a significantly lower occurrence of pain in the lower extremities than those who worked <25 % night shifts (IRR 0.69 95 % CI 0.51, 0.94). There was no indication of a mediation effect with total sleep time (TST). Conclusion: The results of this study indicate that working a higher monthly proportion of night shifts is not associated with a higher occurrence of musculoskeletal pain and headaches.