Knowledge Centre

Shift workers know that multiple strategies need to be used to stay vigilant on night shift. Whilst getting enough sleep in preparation for night shift is important, there are many other strategies used during the shift as well, particularly if the task is boring, monotonous and conducted at low circadian times (i.e. 00:00 to 06:00). The following strategies are commonly cited as strategies used by shift workers to ensure their vigilance and safety whilst undertaking their tasks:

If you are a shift worker and have other strategies not listed, please do not hesitate to contact us at enquiries@ethoshealth.com.au to share your intelligence with other shift workers.

Task

• Schedule additional breaks
• Rotate to alternative tasks
• Remove from safety sensitive work
• For monotonous task, provision of additional stimulus (e.g. trivia)
• Provide transport home or use accommodation.

Supervision

• Work together with other personnel
• Regular check-ins with supervisor/peer

Take a break

• Take a break/rest
• Have a conversation
• Eat something (meal or snack)
• Drink (water or other fluid)
• Drink coffee, tea or a caffeinated drink
• Physical activity
• Relax or stretch
• 15-20 min sleep/nap

Environmental

• Increase ventilation/airflow
• Adjust light
• Change temperature

In a 2018 article in the British Medical Journal (BMJ 2018;360:j5637 doi: 10.1136/bmj.j5637 [Published 1 March 2018]) the topic of optimsing sleep for night shift was covered with the aim to provide sleep management skills for the individual.

The article presents the best evidence from trials, guidance material and expert opinion, but outlines the limited amount of high-quality evidence and that sleep and performance are complex, and highly variable depending on individuals and environmental factors. Thus, it is unlikely that a single intervention will act to optimise sleep, but rather a multilayered approach be taken by individuals to build their own sleep strategies and fine tune approaches that work for them personally. Below is a summary of the findings of the review, and the suggested strategies captured in an infographic by the authors that can be sources and printed at this link.

Background

• Working at night disrupts the circadian rhythm and can lead to the accumulation of a sleep debt, impairing performance and health.
• Full circadian adaptation to night shift work is not possible in the short term.
• Night shift workers should be aware of reduced performance during critical tasks and on the journey home.

Minimising sleep debt before nights

• Performance is impaired when a person achieves two hours less sleep than required, and performance deteriorates progressively. Thus, the following tips strive to get as much sleep at the beginning of a set of night shifts is the initial goal.
• Go to bed at usual time on the evening prior to the first night shift
• Allow unrestricted sleep on the morning before shift (waking without an alarm)
• Supplement sleep time by napping (ideally 60-90min) during the afternoon prior to beginning night shift (during the circadian dip between 2-6pm)

Optimising performance on night shift

• Napping has been shown to improve alertness and performance.
  • Keep naps to less than 30 minutes, to avoid sleep inertia.
• Caffeine has been shown to improve cognitive performance during shift work.
  • Peak onset is 20-45 minutes and lasts 3-5 hours.
  • Avoid caffeine 3-4 hours prior to sleep to avoid sleep disruption.
• Bright light exposure during shifts might reduce sleepiness by inhibiting secretion of melatonin.
• Eat your main meal immediately before night shift and just enough to remain comfortable during the shift.

Between shifts

• Shift worker get conflicting signals from environmental, light and social cures during days between shifts, making circadian adaptation impossible during short term rotation shift work. Therefore, the goal is to get as much sleep between shifts to offset the accumulated sleep debt by eliminating factors that can disrupt sleep including:
  • Avoid bright daylight on journey home (wear UV protective glasses)
  • Avoid blue screens on computers and phones
  • Create dark, quiet and cool environment for sleeping (i.e. blackout blinds, eye masks, ear plugs or white noise generators, fans and/or air conditioning)
  • Create a predictable routine before bed (e.g. bath, reading, gentle stretch, meditation app).
  • Avoid stimulants such as caffeine and/or nicotine before bed.
  • Seek advice from your doctor regarding sleep medication.

Resetting after nights

• Balance repayment of sleep debt with the return to normal sleep rhythm by:
  • Taking a nap of 90-180 minutes,
  • Going outside in the sun, doing activities of daily living, socialise and be as physical active as possible, and
  • Aim to go to bed as near to the usual (family) sleep time as possible.

There is a body of evidence that supports the statement that shift work can detrimentally impact on health, as well as, other factors that impact on human wellbeing and safety (i.e. alertness, fatigue, cognitive performance).

Rather than provide a detailed review of the literature, attached is an editorial of a group of publications from the Scandinavian Journal of Work, Environment and Health [1] that provide a reasonable summary of the body of evidence to answer the question.

It concludes, “that we have sufficient knowledge to conclude that shift work may indeed have detrimental consequences for health, despite the lack of information on all the possible health outcomes and the knowledge gaps related to exposure assessment and specific disease mechanisms. There is also a fairly large body of evidence showing how the negative consequences of shift can be prevented by countermeasures on both the individual and organizational level, although well-controlled intervention studies are rare.”

• a number of reviews and discussion papers on shift work and health, focusing on risk of cardiovascular disease, cancer, eating habits, diabetes, poor mental health, and gastrointestinal disorders provides core evidence on the detrimental effects of shift work on health…taking this all together, shift work is probably related to a wide range of public health problems…Although the risk estimates for the outcomes are low (OR about ≤2)…
• Two recent systematic reviews suggest that shift work probably increase the risk of ischemic heart disease and breast cancer. This “probably” means that, although the evidence for causal associations is still limited, the observed associations are unlikely to be explained by chance, bias or confounding.
• Problems relating to exposure assessment [i.e. how long has someone done shiftwork, at what intensity], study design, and statistical analysis, as well as controlling for relevant confounders are still common, making the possibility for accurate interpretations of the studies’ findings difficult.
• Whilst there is an association between shift work and detrimental health outcomes the knowledge of the pathways and mechanism remain unclear…In their review, Sallinen & Kecklund [2] suggest that sleep and work-related alertness are ameliorated by reducing the number of consecutive night shifts, avoiding long or early-morning shifts, and permitting sufficient time for sleep and rest between work shifts. However, the beneficial effects are rather modest and, even with a sleep-friendly shift system that minimizes circadian disruption, sleepiness is still relatively high during night time.

It is also important to note that shift work may disturb health by way of several psychosocial, behavioural and physiological mechanisms include an array of modifiable lifestyle risk factors, including smoking, nutrition, alcohol, physical activity, stress, heath surveillance, obesity, and sleep; which can all independently contribute to cardiovascular disease, cancer, diabetes, poor mental health, and gastrointestinal disorders.

One of the primary impacts of shift work is its disruption to the normal sleep/wake cycle and consequently reduce a person capacity to attain sufficient sleep to maintain optimal health. Gallicchio et al (2009) in their meta-analysis did show that a reduction in sleep duration increased mortality in adults where short sleepers (<7 hours) had a higher relative risk of all-cause mortality, cardiovascular- and cancer-related mortality [3]. This was also found for long sleepers (>9 hours), suggesting the optimal amount of sleep for optimal health was between 7 to 9 hours.

However, Horne (2010) [4] argued, citing a range of other evidence, that “healthy adults, whose habitual daily sleep is 6 h or thereabouts, should not be concerned that this amount of sleep, alone, is any more likely to lead to illness or death than for 7–8 h sleepers unless there is also Excessive Daytime Sleepiness (EDS), when the more likely immediate concern is having a sleepiness-related accident…Where there is a greater mortality risk for habitual very short sleepers (e.g. <5 h) it is probably largely due to waking pressures and life-style factors also causing short sleep, especially as there is no evidence that extra sleep, alone, will rectify these latter problems.”

Considering these findings and the requirement for shift work in a range of other industries, ongoing review of the health risks associated with shift work is needed. As well as ongoing exploration of prevention, detection and treatment of shift work related problems to alleviate the health problems associated with shift work.

1. Harma, M. and G. Kecklund, Shift work and health - how to proceed? Scand J Work Environ Health, 2010. 36(2): p. 81-4.
2. Sallinen, M. and G. Kecklund, Shift work, sleep, and sleepiness - differences between shift schedules and systems. Scand J Work Environ Health, 2010. 36(2): p. 121-33.
3. Gallicchio, L. and B. Kalesan, Sleep duration and mortality: a systematic review and meta-analysis. J Sleep Res, 2009. 18(2): p. 148-58.
4. Horne, J., Habitual 'short sleep': six hours is 'safe'. J Sleep Res, 2010. 19(1 Pt 1): p. 119-20.

“Mouth breathing”, as opposed to “nose breathing,” has been linked with a variety of health issues including sleep. Mouth breathing may be a matter of habit for some individuals, whereas nasal passage obstruction may be the cause for other people. Both can be treated.

Signs that you are mouth breathing may include dry mouth, bad breath as a result of altered bacterial population, as well as, increase prevalence of oral and upper respiratory infections.

Mouth breathing has the potential to disrupt restorative sleep and is associated with increased the risk of snoring and obstructive sleep apnoea. If you wake in the morning and/or continue to feel drowsy, tired or lethargy and have other symptoms associated with mouth breathing it is recommended you see your doctor to explore whether this is impacting on your sleep or whether other reasons are causing your fatigue symptoms.

Light is captured through photoreceptors in the eyes which transmit this to the suprachiasmatic nucleus (SCN), or internal body clock, via a dedicated neural pathway. Each day the light-dark cycle resets the internal clock, which in turn synchronizes physiological and behavioural patterns known as our circadian rhythms.

People who are visual impaired with no perception of light, experience circadian desynchrony through a failure of light information to reach the SCN, which may result in poor sleep, daytime sleepiness reduced alertness and performance. All can impact on social and work life.

Daily melatonin administration, which provides a replacement synchronising daily “time cue,” is a promising therapeutic strategy, although optimal treatment dose and timing remain to be determined. [1]

If you are experiencing any sleep related problems that you believe are related to being visually impaired, it is recommended to consult with your doctor to explore methods of managing treatment options.

[1] Lockley SW, Arendt J, Skene DJ. Visual impairment and circadian rhythm disorders. Dialogues Clin Neurosci. 2007;9(3):301-14. doi: 10.31887/DCNS.2007.9.3/slockley. PMID: 17969867; PMCID: PMC3202494.

It is still largely unknown how many exact hours of sleep per day are needed in adults, according to their age, their environmental and socio-cultural characteristics. It is generally cited that 7-8 hours of sleep is sufficient for adults and there is ongoing research to identify what is the optimal sleep need. However, there is increasing evidence that shows that sleeping too little or too much impacts on health and mortality. Whilst not as strongly correlated as shorter sleep (<5 hours per day) there is evidence that long sleepers (>10 hour per day) is associated with poorer mental health, obesity, diabetes, hypertension or other cardiovascular diseases, as well as, higher mortality risk.[1]

[1] Léger, Damien et al. “The risks of sleeping "too much". Survey of a National Representative Sample of 24671 adults (INPES health barometer).” PloS one vol. 9,9 e106950. 16 Sep. 2014, doi:10.1371/journal.pone.0106950

Trying to develop good sleep hygiene practices will be a crucial part of falling asleep more quickly.

1. Stick to a bedtime routine (remember your routine starts with your waking time. A consistent waking time will set a consistent urge (approx. 16-7 hours) to sleep in the evening)
2. Relax and avoid stimulating activities before going to bed (e.g. social media)
3. Avoid caffeine and nicotine
4. Avoid alcoholic drinks
5. Avoid large meals or lots of fluids
6. Take medication as prescribed by a medical professional
7. Avoid afternoon naps
8. Create a cool, dark, quiet environment for sleeping
9. Sunlight exposure (preferably in the morning and for >30mins)
10. Address anxiety provoking thoughts that stop you sleeping (list thoughts in notebook, breathing, mediation, remove visible clocks)

If you have followed the tips above and are still having trouble sleeping, it is recommended you see your doctor to explore other reasons for your disrupted sleep.

Many women report disturbed sleep during perimenopause and menopause. This often includes difficulty falling or staying asleep and waking through the night or very early in the morning. There are many possible contributing factors during this period, including:

• Changing hormone levels (hormones playing a role in sleep include growth hormone, prolactin, cortisol and melatonin)
• Vasomotor symptoms (sweating and flushing) and mood disorders (depression and anxiety)
• Abnormalities in circadian rhythm
• Other health issues (snoring, airway obstruction, restless legs syndrome, periodic limb movement disorder, musculoskeletal pain and fibromyalgia)
• Existing sleep issues (insomnia)
• Lifestyle factors (poor sleep hygiene, irregular schedules, caffeine, alcohol, snoring partner).

To improve sleep during perimenopause and menopause, the contributing factors that are specific to you will need to be addressed. Effective strategies may include medication and lifestyle changes but it is also important to consider your sleep habits, particularly those relating to sleep hygiene, which form an important foundation for good sleep. Sleep hygiene includes regular sleep schedules, avoiding caffeine and alcohol, appropriate and comfortable bedding and temperatures (Search “Top 10 Sleep tips” on Fatigue Tech Knowledge Centre.). In addition, the body’s production of melatonin declines with age affecting our sleep-wake cycle. To improve your circadian rhythm, exposure to daylight at the time of waking combined with walking can help consolidate night-time sleep and reduce early morning wakefulness. Discuss your sleep disturbances with your GP who can determine whether your sleep issues can also be managed with menopausal hormone therapy (MHT) or specific medications.

Further information:

Sleep problems and menopause: What Can I Do?
National Institute on Aging   https://www.nia.nih.gov/health/menopause/sleep-problems-and-menopause-what-can-i-do

The Australasian Menopause Society website (www.menopause.org.au)For information and resources or search the register to find a GP who has a special interest in women’s health in midlife and menopause
https://www.menopause.org.au/health-info/find-an-ams-doctor