Sleep and food are truly amongst the most basic of needs – in fact, they’re on the same level as breathing (and excretion!) on Maslow’s pyramid of needs. Even the CanMEDS framework of the Royal College states that as a Professional, physicians must be able to manage personal and professional demands to maintain a sustainable practice.
In 2011, 1.8 million Canadians (12% of the working population) were exposed to night shiftwork, with 45% of them being female. The highest prevalence by occupation was protective services (37%), healthcare workers (35%), and manufacturing (24%). When considering not just nightshifts, but all shiftworkers, numbers rise as high as 28% – over a quarter of the working population!
Clearly, a lot of people are doing shiftwork…..
The implications of shiftwork are enormous.
- ECONOMIC: On an economic level, there are additional costs associated with work-related accidents and injuries, insuring for these accidents and injuries, and retraining for new employees due to higher turnover rates.
- SOCIAL: On a social level, it’s quite simply difficult to be social when you work a lot of evenings and nights – shiftworkers are twice as likely to be divorced and much more likely to be engaged in substance misuse.
- HEALTH: And of course, the health risks involved with shiftwork are well-known, from everything metabolic (hypertension, diabetes, obesity, dyslipidemia) to increased risk of motor vehicle collisions, depression, and even infertility and immune dysfunction. In 2007, the International Agency for Research on Cancer classified shiftwork as a Group 2A carcinogen, placing it in the same class as lead, UV radiation, and insecticides. Consequently, in 2011, Cancer Care Ontario also acknowledged that shiftwork in Canadian industries is a probable cancer risk factor.
There is even evidence that shiftwork may be shrinking your brain!
Why is this particularly important to emergency physicians? A survey of more than 1,000 emergency physicians in the USA showed that:
- 58% felt night shiftwork negatively influenced job satisfaction
- 43% indicated that nightshifts had caused them to think about leaving emergency medicine
- Perhaps most alarmingly, among those who had left emergency medicine, 56% said that late evenings and nightshifts were a major factor in their decision to leave
Shiftwork is an integral part of emergency medicine and yet is simultaneously a huge reason for turnover. We must learn to effectively deal with shiftwork to not only survive, but to THRIVE.
First, let’s talk about how things get set up for a nightshift. We’ve all been there before. You’re about to start a string of three nightshifts. There’s a lot already going on with your life. You haven’t even started the first night, and you’re already exhausted. You’re laying in bed, and you want to sleep, but the only thought that keeps going through your mind is some variation of: “If I don’t sleep now, I’ll only get 3 hours of sleep.”
So what do you do?
Of course, you get out your phone. Bad move. You know this is a bad move because you’ve heard of sleep hygiene somewhere before, and this is pretty basic.
Michael Jordan didn’t become the greatest of all time by practicing insane windmill dunks or crazy half court 3-pointers. He became the best by sticking to the fundamentals.
Sleep hygiene is the most basic yet perhaps most often neglected aspect of effective sleep.
Let’s review. Sleep hygiene means:
- Making sure your bedroom is quiet, dark, and at a comfortable temperature
- Removing all electronic devices: No work in bed
- Avoiding large meals, caffeine, and alcohol before bedtime
- Getting regular exercise (but not too close to bedtime)
For sure, these are the fundamentals and a great place to start. But even under ideal sleep hygiene conditions, it’s not always easy to fall asleep.
How do people in the worst possible sleeping conditions do it?
The Skill of Sleep
The US Naval Pre-flight School has been training its pilots to sleep under terrible conditions since World War 2. They have highly effective program for getting their pilots to fall asleep in under 2 minutes. And that’s even with coffee and simulated machine gunfire in the background. Initially published in 1981, this technique became famous after going viral on a 2018 blog post. By the end of 6 weeks of practice, 96% of the pilots were consistently able to fall asleep in under 2 minutes.
Sleeping, much like everything else we do in medicine, is a skill.
If it can be practiced, it can be perfected.
The Dangers of the Night
A landmark study in Nature from 1997 showed how fatigue could cause just as much impairment as alcohol use. The study took 40 subjects and split them into two groups, where one was kept awake for 28 hours, and the other consumed alcohol at regular intervals until their blood alcohol concentration (BAC) was 0.1%. After 17 hours of sustained wakefulness, the results showed cognitive and psychomotor performance decreased to a level equivalent to the impairment observed at a BAC concentration of over 0.05%, which is the legal limit in many places throughout North America. Multiple other studies have replicated these findings.
A study from the University of Texas in 2016 was the first of its kind – it examined the impact of nightshift work on measures of drowsiness and driving performance while operating an actual motor vehicle on a closed track. Of the 16 post-sleep drives, there were zero near-crashes or early drive terminations. Of the 16 post-nightshift drives, 7 of 16 were terminated early for safety reasons. The authors concluded what we all intuitively know, which is that night shiftwork increases driver drowsiness, degrades driving performance and increases the risk of near-crash events.
And this risk is not theoretical. A cross-sectional study from 2021 of 273 residents in British Columbia doing shiftwork found that 54% of residents reported at least one motor vehicle collision (MVC) in the previous year. Furthermore, every additional 10km of travel time equated to an adjusted odds ratio of 1.54 increased risk of MVC on the way home.
Fight the Night with Bright Light
If shiftwork is unavoidable, and shiftwork is dangerous – what can we do about it?
A 2017 RCT used bright light therapy to see if it could help improve safety in sleep-deprived subjects. Towards the end of a simulated nightshift in relatively dark environments, one group of participants was exposed to dim light, and the other to 5600 lux bright light for 45 minutes each. Both groups then completed a driving test. The authors found significantly decreased rates of MVCs in the bright light group.
Light can also help with performance while still on shift.
Bright lights at night significantly increase subjective alertness and cognitive performance in shiftworkers. Numerous studies have demonstrated this going back at least three decades, starting with a landmark study in the New England Journal of Medicine in 1990. There is a reason why casinos look the way they do, and we can take a page out of their playbooks, because this is an opportunity for us to do better.
Keeping nurse and physician workstations as bright as possible overnight could help with performance, with minimal costs. Patient areas can remain dark to help with preventing delirium.
Morning handover could also be an opportunity and location to have bright lights, to
1) improve the safety of the team going home, but also with the added benefit of
2) transitioning the day-team into wakefulness.
Speaking of wakefulness, let’s talk about caffeine. So many of us use it – the big question is: Is it effective? The psychology literature is full of small-scale trials examining the effects of caffeine on cognitive performance. Caffeine seems to facilitate learning. Caffeine appears to improve memory. Caffeine seems to improve reaction times. However, these studies were based predominantly on paper and pencil tests.
Is it useful in real life? A 2010 Cochrane review attempted to assess the effects of caffeine for preventing injuries caused by impaired alertness in shiftworkers. The pooled effect estimates on performance suggested that, when compared to a placebo, caffeine improved concept formation and reasoning, memory, orientation, attention, and perception. So, overall caffeine intake may be beneficial in our line of work. Plus, it’s tasty!
But we don’t know that it improves safety. Despite the title of the review, none of those studies actually measured an injury outcome. Let’s go back to the theme of driving home safely. A recent 2020 study showing that sleep deprivation was just as debilitating as alcohol consumption also demonstrated that coffee was NOT an effective countermeasure for sleep-deprived driving.
If you’ve ever thought a cup of coffee on the way home would help: It does not make you a safer driver.
A 2003 study from the Journal of Biologic Rhythms found that, when used together, bright light, scheduled dark, sunglasses and melatonin were useful in manipulating circadian rhythm for night shift work. We’ve talked about everything else so far, but what is melatonin?
It’s essentially the sleep hormone that is secreted by the pineal gland. More melatonin = More sleepy. In a “typical” dayshift sleep pattern, melatonin release begins around 8:00 pm and peaks at around 3:00 am. This peak lasts until about 5:00 am, which is why the hours of 3:00 to 5:00 am are the witching hours for the night shiftworker. You feel sluggish, foggy, and at peak fatigue during these hours.
By 7:00 am, our melatonin levels have fallen significantly. Its release is further inhibited by light exposure, and thus levels are negligibly low throughout the daylight hours. This is one of the reasons why it’s difficult for shiftworkers to fall into a restful daytime sleep. Interestingly, melatonin decreases with age, which partly explains why your grandparents are up at 4:00 am every day, and why teenagers seem to sleep till the afternoon and get called lazy. It’s their melatonin!
There is a lot of research surrounding melatonin and its use in helping with insomnia and shiftwork. A meta-analysis from 2013 showed that melatonin helped fall asleep faster, increased total sleep time, improved overall sleep quality, and had a favourable side effect profile. Even more relevant to us as shiftworkers, a 2014 Cochrane review showed that melatonin after a night shift was associated with increased daytime sleep duration.
The effects, however, are modest. The time required to fall asleep, or sleep latency, improved by an average of 7 minutes, depending on the review. This may not sound like much on the surface, but considering average sleep latency is 10 to 20 minutes, 7 minutes could be regarded as significant. Total sleep time increased by about 8-24 minutes, depending on the trial. So overall, the effects are modest, but the harm is quite minimal.
Reassuringly, the meta-analyses showed no dose-response association, and the effects did not appear to fade with continued melatonin use. There was thus no habituation. It’s safe, affordable and definitely worth trying to see if it helps you. Melatonin can reasonably be used:
1) in the afternoon before a night shift, to help flip into a nocturnal rhythm;
2) in the morning after a night shift to stay in the nocturnal rhythm and get more daytime sleep ahead of more night shifts, or;
3) after a string of nights, the following evening, to help flip back into a daytime rhythm.
There are several apps out there, like Headspace for example, designed around mindfulness. They help users practice meditation, deep breathing, relaxation, and general mental wellness. Most of these apps feature a sleep component: mental exercises, stories, or sounds designed to help promote better sleep.
One of the most studied is an app called Calm. According to a cross-sectional survey, 90% of its users have sleep difficulties, and 77% started using the app primarily for sleep. So you wouldn’t be alone in trying it – and you wouldn’t be wrong to either. According to a randomized controlled trial (RCT) from Arizona State, 10 minutes a day for 8 weeks is all it took to get significant improvements in sleep quality. A cross-sectional survey run by the same group showed that the majority of participants using Calm reported that it helped them fall asleep, stay asleep, and get more restful sleep.
These are relatively inexpensive, low commitment interventions that may seem like mumbo jumbo at first, but are proven to work, not only through modern scientific research, but the hundreds of years behind the history of meditation techniques.
SLEEP: TAKE-HOME MESSAGES
- Sleep is a skill
- It can be practiced, and perfected
- Respect sleep hygiene discipline
- Adjuncts can help
- Apps like Calm can be helpful
- Melatonin is modestly effective and quite safe
- Caffeine can help with alertness but not necessarily safety
- Night shiftwork can be dangerous
- Driving home post-nights can be fatal
- Light therapy is a safe, inexpensive tool that can improve both performance overnight and safety going home
- Sleep is a skill
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