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Practice Essentials

Optimising sleep for night shifts

BMJ 2018; 360 doi: (Published 01 March 2018) Cite this as: BMJ 2018;360:j5637
cropped thumbnail of infographic

Visual summary available

A suggested sleep strategy covering before, during, and after night shifts

Is individual responsibility the answer to optimising sleep at work to improve safety?

I read with interest the paper by McKenna and Wilkes (BMJ 2018; 360: j5637), their infographic and your Editorial (BMJ 2018; 360: k947). I am pleased to see greater interest in the subject more than 10 years since the problem was raised by a number of articles in the US1-4 and in the UK5-7. There is strong evidence from clinical trials to indicate that long and frequent shifts, especially in junior doctors' rotas, lead to harm to patients and to doctors, due to tiredness, fatigue, attentional failures and cognitive impairment1-4,7. The recent article aims to provide guidance to shift workers (specifically doctors) on how to cope with these problems individually. However, the article may give the false impression that changing individual behaviour will solve the problem. The importance of barriers to implementing the measures suggested are underestimated, as individual choices are too often frustrated by unfavourable environmental and organizational structures. Unsafe working patterns are often adopted by individuals due to economic and societal pressures5 and, without institutional fail-safe mechanisms and sound organizational structures and rota designs, patients would have every right to be concerned about being cared for by a tired doctor, and doctors, likewise, about their personal safety.

In the first randomized trial conducted in an NHS hospital in the United Kingdom, junior doctors were assigned to either a 48h/week EWTD-compliant rota or to a 56h/week standard rota7. Medical errors were assessed in a blind fashion over a 12-wk period. The 'intervention' rota not only included reduced weekly working hours, but it had several important components that were based on well-established principles of sleep medicine and circadian biology8. First, it limited consecutive night shifts to three nights maximum, in order to reduce the build-up of chronic partial sleep deprivation due to the limited sleep between night shifts. Second, shift duration was limited to 12h maximum to minimize acute sleep deprivation. Third, the sequence of shifts was designed to abolish 'slam shifts' in which doctors change from a day to a night shift immediately, which ensures complete circadian desynchrony9, and instead gradually stagger the shifts from morning to evening to night in the direction that the circadian system most easily adapts to10. This sequence also facilitates sleep and reduces performance decrements on the first night shift11 by providing an opportunity for a long recovery sleep after the evening shift prior to starting the first night shift. Finally, the intervention rota reduced the proportion of long work weeks, with an upper limit of 60h per week, again reducing chronic sleep deprivation, in stark contrast to control rota, during which 25% of the shifts were >58 h/week and as long as 77 h/week. The results were striking. The 'intervention' rota was associated with a 33% reduction in medical errors, an increase in total daily sleep time (7.26h v 6.75h), a substantial recovery sleep of nearly 9h after the evening shift, and more frequent naps in the hours preceding the start of the night shifts7.

Despite the evidence, after a prolonged moratorium on the implementation of the EWTD Directive in the UK, in 2009 it became law. Soon afterwards, however, opt-out clauses where developed12 and lobbying at European level led to a reduced and patchy implementation in the NHS. With Brexit looming at the horizon, there is concern that these regulations will be relaxed even more and greater responsibility will be diverted to the individual13.

It is unquestionable that more doctors and health-care providers are needed to implement optimal rotas for doctors and nurses in the NHS. This would require to ring-fence allocated budgets for provision of more staff. This is a difficult scenario to envisage given the inefficient use of resources and recurrent underfunding of the NHS. Given the high negative impact of long hours on doctors' ability to perform safely, however, we cannot ignore the need to find any available opportunity that might have the potential to improve patients' safety and doctors working conditions and personal safety.

Francesco P Cappuccio, DSc FRCP
Professor of Cardiovascular Medicine & Epidemiology and Consultant Physician
University of Warwick, Warwick Medical School, Division of Health Sciences (MHWB)
University Hospitals Coventry & Warwickshire NHS Trust
Coventry, UK

1. Landrigan CP, Rothschild JM, Cronin JW, Kaushal R, Burdick E, Katz JT, et al. Effect of reducing intern's work hours on serious medical errors in intensive care units. N Engl J Med 2004; 351: 1838-48.
2. Lockley SW, Cronin JW, Evans EE, Cade BE, Lee CJ, Landrigan CP, et al. Effect of reducing interns' weekly work hours on sleep and attentional failures. N Engl J Med 2004; 351: 1829-37.
3. Barger LK, Cade BE, Ayas NT, Cronin JW, Rosner B, Speizer FE, et al. Extended work shifts and the risk of motor vehicle crashes among interns. N Engl J Med 2005; 352: 125-34.
4. Barger LK, Ayas NT, Cade BE, Cronin JW, Rosner B, Speizer FE, Czeisler CA. Impact of extended-duration shifts on medical errors, adverse events, and attentional failures. Plos Med 2006; 3: e487.
5. Cappuccio FP, Lockley SW. Safety and the flying doctor. Br Med J 2008; 336: 218
6. Cappuccio FP, Lockley SW, Landrigan CP. EWTD is to improve health and safety of patients and doctors. Br Med J 2008; 337: a3080
7. Cappuccio FP, Bakewell A, Taggart FM, Ward G, Ji C, Sullivan JP, Edmunds M, Pounder R, Landrigan CP, Lockley SW, Peile E on behalf of the Warwick EWTD Working Group. Implementing a 48 h EWTD-compliant rota for junior doctors in the UK does not compromise patients' safety: assessor-blind pilot comparison. Q J Med 2009; 102: 271-282
8. Horrocks N, Pounder R. Working the night shift: preparation, survival and recovery - a guide for junior doctors. Clin Med 2006; 6: 61-7.
9. Czeisler CA, Moore-Ede MC, Coleman RM. Rotating shift work schedules that disrupt sleep are improved by applying circadian principles. Science 1982; 217: 460-3.
10. Czeisler CA, Duffy JF, Shanahan TL, Brown EN, Mitchell JF, Rimmer DW, et al. Stability, precision, and near-24-hour period of the human circadian pacemaker. Science 1999; 284: 2177-81.
11. Santhi N, Horowitz TS, Duffy JF, Czeisler CA. Acute sleep deprivation and circadian misalignment associated with transition onto the first night of work impairs visual selective attention. PLoS One 2007; 2: e1233.
12. British Medical Association. European Working Time Directive: Junior Doctors FAQ. (accessed 7 March, 2018)
13. The Royal College of Surgeons of Edinburgh. Brexit Statement. (Accessed 7 March, 2018)

Competing interests: No competing interests

07 March 2018
Francesco P Cappuccio
Academic Clinician
University of Warwick, Warwick Medical School
Gibbet Hill Road, Coventry CV4 7AL