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- Akerstedt, Torbjörn, et al.
(författare)
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Accounting for partial sleep deprivation and cumulative sleepiness in the Three-Process Model of alertness regulation.
- 2008
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Ingår i: Chronobiol Int. - : Informa UK Limited. - 1525-6073 .- 0742-0528. ; 25:2, s. 309-19
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Tidskriftsartikel (refereegranskat)abstract
- Accounting for partial sleep deprivation and cumulative sleepiness in the Three-Process Model of alertness regulation.Akerstedt T, Ingre M, Kecklund G, Folkard S, Axelsson J.Stress Research Institute, University of Stockholm, Stockholm, Sweden. torbjorn.akerstedt@ki.seMathematical models designed to predict alertness or performance have been developed primarily as tools for evaluating work and/or sleep-wake schedules that deviate from the traditional daytime orientation. In general, these models cope well with the acute changes resulting from an abnormal sleep but have difficulties handling sleep restriction across longer periods. The reason is that the function representing recovery is too steep--usually exponentially so--and with increasing sleep loss, the steepness increases, resulting in too rapid recovery. The present study focused on refining the Three-Process Model of alertness regulation. We used an experiment with 4 h of sleep/night (nine participants) that included subjective self-ratings of sleepiness every hour. To evaluate the model at the individual subject level, a set of mixed-effect regression analyses were performed using subjective sleepiness as the dependent variable. These mixed models estimate a fixed effect (group mean) and a random effect that accounts for heterogeneity between participants in the overall level of sleepiness (i.e., a random intercept). Using this technique, a point was sought on the exponential recovery function that would explain maximum variance in subjective sleepiness by switching to a linear function. The resulting point explaining the highest amount of variance was 12.2 on the 1-21 unit scale. It was concluded that the accumulation of sleep loss effects on subjective sleepiness may be accounted for by making the recovery function linear below a certain point on the otherwise exponential function.
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| 2. |
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| 3. |
- Marquié, Jean-Claude, et al.
(författare)
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Chronic effects of shift work on cognition : findings from the VISAT longitudinal study
- 2015
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Ingår i: Occupational and Environmental Medicine. - : BMJ. - 1351-0711 .- 1470-7926. ; 72:4, s. 258-264
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Shift work, like chronic jet lag, is known to disrupt workers' normal circadian rhythms and social life, and to be associated with increased health problems (eg, ulcers, cardiovascular disease, metabolic syndrome, breast cancer, reproductive difficulties) and with acute effects on safety and productivity. However, very little is known about the long-term consequences of shift work on cognitive abilities. The aim of this study was to assess the chronicity and reversibility of the effects of shift work on cognition.METHODS: We conducted a prospective cohort study of 3232 employed and retired workers (participation rate: 76%) who were 32, 42, 52 and 62 years old at the time of the first measurement (t1, 1996), and who were seen again 5 (t2) and 10 (t3) years later. 1484 of them had shift work experience at baseline (current or past) and 1635 had not. The main outcome measures were tests of speed and memory, assessed at all three measurement times.RESULTS: Shift work was associated with impaired cognition. The association was stronger for exposure durations exceeding 10 years (dose effect; cognitive loss equivalent to 6.5 years of age-related decline in the current cohort). The recovery of cognitive functioning after having left shift work took at least 5 years (reversibility).CONCLUSIONS: Shift work chronically impairs cognition, with potentially important safety consequences not only for the individuals concerned, but also for society.
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| 4. |
- Tucker, Philip, et al.
(författare)
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The impact of junior doctors' worktime arrangements on their fatigue and well-being
- 2010
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Ingår i: Scandinavian Journal of Work, Environment and Health. - : Scandinavian Journal of Work, Environment and Health. - 0355-3140 .- 1795-990X. ; 36:6, s. 458-465
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Tidskriftsartikel (refereegranskat)abstract
- Objective Many doctors report working excessively demanding schedules that comply with the European Working Time Directive (EWTD). We compared groups of junior doctors working on different schedules in order to identify which features of schedule design most negatively affected their fatigue and well-being in recent weeks. Methods Completed by 336 doctors, the questionnaires focused on the respondents’ personal circumstances, work situation, work schedules, sleep, and perceptions of fatigue, work–life balance and psychological strain. Results Working 7 consecutive nights was associated with greater accumulated fatigue and greater work–life interference, compared with working just 3 or 4 nights. Having only 1 rest day after working nights was associated with increased fatigue. Working a weekend on-call between 2 consecutive working weeks was associated with increased work–life interference. Working frequent on-calls (either on weekends or during the week) was associated with increased work–life interference and psychological strain. Inter-shift intervals of <10 hours were associated with shorter periods of sleep and increased fatigue. The number of hours worked per week was positively associated with work–life interference and fatigue on night shifts. Conclusion The current findings identify parameters, in addition to those specified in the EWTD, for designing schedules that limit their impact on doctors’ fatigue and well-being.
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| 5. |
- Tucker, Philip, et al.
(författare)
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Work Scheduling
- 2012. - 1
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Ingår i: The Handbook of Operator Fatigue. - Farnham : Ashgate. - 9780754675372 - 9781315557366 ; , s. 457-468
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Bokkapitel (refereegranskat)
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| 6. |
- Tucker, Philip, et al.
(författare)
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Working time, health and safety : a research synthesis paper
- 2012
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Rapport (refereegranskat)abstract
- It is hoped that this study will provide useful guidance regarding how to respond to new trends and developments in the area of working time and develop innovative, mutually beneficial working-time arrangements without compromising workers’ health and workplace safety.
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| 7. |
- Åkerstedt, Torbjörn, 1946-, et al.
(författare)
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Predictions from the Three-Process Model of Alertness
- 2004
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Ingår i: Aviation, Space, and Environmental Medicine. - : Aerospace Medical Association. - 0095-6562. ; 75:3, Suppl., s. A75-A83
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Tidskriftsartikel (refereegranskat)abstract
- This paper summarizes a computer model for predicting alertness/performance in daily life. The model uses the timing of work hours (and/or sleep hours) as input and uses both a circadian and a homeostatic component (amount of prior wake and amount of prior sleep) that are summed to yield predicted subjective alertness (on a scale between 1 and 21). The model also includes prediction of psychomotor performance on various tasks, an identification of levels at which the risk of performance/alertness impairment start, as well as a prediction of sleep latency and time of awakening from sleep. The model is currently being used to evaluate work/rest schedules for navy, airline and railway applications. It is also used for teaching sleep/wake regulation and for generating research hypotheses.
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