Daytime napping and its effects on alertness and short-term memory performance in shiftworkers

Härmä, Mikko; Knauth, Peter; Ilmarinen, Juhani

doi:10.1007/bf00409390

Cited by 36 publications

(3 citation statements)

References 12 publications

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“…Future studies could investigate whether potential benefits of a shorter period of prior wake outweighs the effects of sleep loss and are associated with improved night shift performance for early chronotypes using a strategically delayed sleep. Future research could also assess the impact of chronotype on the effect of a delayed main sleep combined with a nap, as daytime naps alleviate sleep pressure and improve performance during the first night shift (Akerstedt, 2003; Åkerstedt, 1998; Boivin & Boudreau, 2014; Harma et al, 1989; Kosmadopoulos et al, 2016; Macchi et al, 2002; Mchill & Wright Jr., 2019; Purnell et al, 2002). As chronotype shows a relationship with sex (Roenneberg et al, 2003), future studies could also examine differences between males and females in the effects of chronotype on sleep during normally timed and delayed sleep opportunities.…”

Section: Discussionmentioning

confidence: 99%

The night before night shift: Chronotype impacts total sleep and rapid eye movement sleep during a strategically delayed sleep

Reiter

Roach

Sargent

2022

Journal of Sleep Research

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Summary Transition to night shift may be improved by strategically delaying the main sleep preceding a first night shift. However, the effects of delayed timing on sleep may differ between chronotypes. Therefore, the study aim was to compare the impacts of chronotype on sleep quality and architecture during a normally timed sleep opportunity and a delayed sleep opportunity. Seventy‐two (36 female, 36 male) healthy adults participated in a laboratory study. Participants were provided with a normally timed sleep opportunity (23:00–08:00) and a delayed sleep opportunity (03:00–12:00) over two consecutive nights in a sleep laboratory. Sleep was monitored by polysomnography (PSG), and chronotype was determined from dim light melatonin onset (DLMO). A tertile split of DLMO defined early (20:24 ± 0:42 h), intermediate (21:31 ± 0:12 h), and late chronotype (22:56 ± 0:54 h) categories. Although there was no main effect of chronotype on any sleep measure, early chronotypes obtained less total sleep with delayed sleep than with normally timed sleep (p = 0.044). Intermediate and late chronotypes obtained more rapid eye movement (REM) sleep with delayed sleep than with normally timed sleep (p = 0.013, p = 0.012 respectively). Wake was more elevated for all chronotypes in the later hours of the delayed sleep opportunity than at the start of the sleep opportunity. Strategically delaying the main sleep preceding a first night shift appears to benefit intermediate and late chronotypes (i.e., more REM sleep), but not early chronotypes (i.e., less total sleep). Circadian processes appear to elevate wakefulness for all chronotypes in the later stages of a delayed sleep opportunity.

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Section: Discussionmentioning

confidence: 99%

The night before night shift: Chronotype impacts total sleep and rapid eye movement sleep during a strategically delayed sleep

Reiter

Roach

Sargent

2022

Journal of Sleep Research

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“…Napping has been shown to be an effective tool for managing sleep deprivation and dysrhythmia brought about by chronic or acute circadian disruption [22]. The negative physical and psychological symptoms of disrupted sleep are improved by naps during the day or nightshifts [23-27]. Additionally, in healthy, well-rested subjects, napping has been shown to improve performance across a range of memory tasks [28-35].…”

Section: Discussionmentioning

confidence: 99%

The effect of nap frequency on daytime sleep architecture

McDevitt

Alaynick

Mednick

2012

Physiology & Behavior

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It is well documented that the quality and quantity of prior sleep influences future sleep. For instance, nocturnal sleep restriction leads to an increase in slow wave sleep (SWS) (i.e. SWS rebound) during a subsequent sleep period. However, few studies have examined how prior napping affects daytime sleep architecture. Becuase daytime naps are recommended for management of disrupted sleep, understanding the impact of napping on subsequent sleep may be important. We monitored sleep-wake patterns for one week with actigraphy followed by a 75-minute polysomnographically-recorded nap. We found that greater nap frequency was correlated with increased Stage 1 and decreased SWS. We categorized subjects based on nap frequency during the prior week (0 naps, 1 to 2 naps, and 3 to 4 naps) and found differences in Stage 1, Stage 2, and SWS between groups. Subjects who took no naps had the greatest amount of SWS, those who took 1 to 2 naps had the most Stage 2 sleep, and those who took 3 to 4 naps had the most Stage 1. While correlations were not found between nap frequency and nocturnal sleep measures, frequent napping was associated with increased subjective sleepiness. Therefore, frequent napping appears to be associated with lighter daytime sleep and increased sleepiness during the day. Speculatively, low levels of daytime sleepiness and increased SWS in non-nappers may help explain why these individuals choose not to nap.

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“…Fortunately, coping strategies, such as daytime napping before a night shift, can contribute greatly to both the social and health consequences of shift work (Fig. 1 , panel b) [ 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

The effect of chronotype on sleepiness, fatigue, and psychomotor vigilance of ICU nurses during the night shift

et al. 2015

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PurposeIn general, sleeping and activity patterns vary between individuals. This attribute, known as chronotype, may affect night shift performance. In the intensive care unit (ICR), night shift performance may impact patient safety. We have investigated the effect of chronotype and social demographics on sleepiness, fatigue, and night shift on the performance of nurses.MethodsThis was a prospective observational cohort study which assessed the performance of 96 ICU night shift nurses during the day and night shifts in a mixed medical–surgical ICU in the Netherlands. We determined chronotype and assessed sleeping behaviour for each nurse prior to starting shift work and before free days. The level of sleepiness and fatigue of nurses during the day and night shifts was determined, as was the effect of these conditions on psychomotor vigilance and mathematical problem-solving.ResultsThe majority of ICU nurses had a preference for early activity (morning chronotype). Compared to their counterparts (i.e. evening chronotypes), they were more likely to nap before commencing night shifts and more likely to have young children living at home. Despite increased sleepiness and fatigue during night shifts, no effect on psychomotor vigilance was observed during night shifts. Problem-solving accuracy remained high during night shifts, at the cost of productivity.ConclusionsMost of the ICU night shift nurses assessed here appeared to have adapted well to night shift work, despite the high percentage of morning chronotypes, possibly due to their 8-h shift duration. Parental responsibilities may, however, influence shift work tolerance.

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Daytime napping and its effects on alertness and short-term memory performance in shiftworkers

Cited by 36 publications

References 12 publications

The night before night shift: Chronotype impacts total sleep and rapid eye movement sleep during a strategically delayed sleep

The night before night shift: Chronotype impacts total sleep and rapid eye movement sleep during a strategically delayed sleep

The effect of nap frequency on daytime sleep architecture

The effect of chronotype on sleepiness, fatigue, and psychomotor vigilance of ICU nurses during the night shift

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