This is not a blog post on why good sleep is essential or about the physiology underlying human sleep/wake cycle. Many folks have written about this and I will add some good resources at the bottom of this page. This is a condensed version of a talk Jamie and myself give about shift work with a focus on how I personally cope with being a shift worker and the strategies that seem to work as borne out by my own personal experience and also the experience of others who have been on a receiving end of this talk: from nurses to air traffic controllers.
Something obvious that gets missed in the conversation about shift work – it is not all about nights.
Most shift workers do a combination of day shifts, evening shifts, and night shifts. If you are working only or primarily nights you will need a strategy specific to your nocturnal lifestyle and this post may not be for you.
My own shifts vary between a day shift (any time between 7am and 5pm), evening shift (4pm to 1am), night shift (11.30pm to 7.30am) and an occasional “swing shift” (any time between 10am and 8pm). Some people have a set roster, e.g. they do 5 nights in a row followed by 5 days. Some people including myself, have a fairly random schedule: 2 mornings, followed by 2 evenings, followed by a night, swing shift, morning shift, – you get the picture. Recently I have locked in my shifts into a more predictable pattern but it is essentially still a mix.
So what do you do and how the hell do you plan your sleep around a 24/7 schedule?
A few key considerations:
- Circadian rhythm vs. hours slept.
In my experience, people focus to much on the latter and not enough on the former. Yes, sleep duration is important but the goal of sleep management for shift workers is to MINIMISE THE SHIFT. Under some circumstances, sleeping less is more advantageous than sleeping more but screwing up your sleep-awake cycle in the process. I know somebody’s bubble of certainty just exploded into a billion pieces. Stop beating yourself up for not sleeping 8 hours during the day after the night shift.
- Sleep cycles vs hours slept
The magic number 8 (as in 8 hours) is a social construct born out of the industrial action of the early 20th century when the unions demanded fair conditions for workers which included “8 hours work, 8 hours sleep, 8 hours leisure”. Our bodies operate on an ultradian rhythm with each cycle lasting APPROXIMATELY 90 minutes. Five cycles of sleep gives you 7.5 hours, six cycles gives you 9 hours. APPROXIMATELY. Setting your alarm for 8 hours exactly may wake you up in the middle of the cycle, causing sleep inertia. Waking up half an hour earlier than the alarm may signal the end of the cycle. Don’t try to go back to sleep just to steal the last 25 minutes. You will dive back into deep sleep and feel like crap when the alarm goes off. If you are sleeping during the day you might find it helpful to break your total sleep times into sleep cycle blocks: eg. 3 cycles in the morning, 2 cycles in the afternoon
- Minimise the jet-lag
When you travel across the time zones you shift your circadian rhythm. When you change your awake/sleep time with shift work you effectively travel across time zones which is why you feel like you are permanently jet-lagged. It is recognised that each hour of circadian shift takes about a day of adjustment. A two-hour time shift seems to be about the limit of what you can easily handle physiologically. Anything over 2 hours is a jet-lag territory. As I said, your goal should be to MINIMISE THE SHIFT. If you are switching between days and evenings you don’t want your morning wake up time to vary widely. Some people wake up at 5.30am for an early morning start but sleep in till 11am or midday for their 4/5pm start. Bad idea. Minimise the gap. The closer to 2 hours the better.
- Anchor the rhythm
Whatever combination of days/evenings/nights you are doing, chances are you are still doing more days then overnights. Plus, when you have a day off you want to be awake during the day. (Once again, if you work only/predominantly night shifts this may not apply to you.) So it makes sense to anchor your rhythm to days as much as possible, viewing your night shift as a temporary perturbation. There are three main environmental anchors to our circadian rhythm:
- Physical activity
You don’t want to be eating a meal at 3am on your night shift.
You don’t want to be sleeping through ALL the daylight hours and not see the sun for several days in a row.
You don’t want to be a sloth during the day and save all your physical activity to nighttime.
No matter what shift you do, eat at ROUGHLY the same time, see the light at SOME point during the day, be active at ROUGHLY the same time.
- Specific recovery strategies
Respecting the circadian physiology means that we schedule our life around my shift work. Our training is scheduled around my shifts in such a way that I never do strength or conditioning work after 3 late shifts in a row. I am also a big fan of naps. I have a nap most days that I work in the evenings (more on napping in the next post). My days off usually involve going out in nature: either hiking or mountain biking. I have discovered that if I don’t go out in nature on my day off I have a much harder time at work the following day: less focus, less motivation, less empathy (important!). Hence, we make it our priority to go somewhere where we can be among the trees, mountains, or stunning harbour views. Luckily, living in Christchurch, it’s not hard.
- Don’t expect miracles
We are diurnal creatures. No matter how much you hack, how fancy your blue blockers are, or how many sleep apps you get, shift work will affect you. Don’t be an ostrich. Mitigation strategies are just that: they are not solutions. Why do you work shift? What’s your health cost to benefit ratio? Can you avoid it and still get the same benefit (career, money, recognition)? If you choose to do it – be aware of the consequences. On a daily basis this means recognising that you shouldn’t be aiming to set any PRs on the week with maximum circadian rhythm disruption. You will be hungrier and crave more sweets after evening/night shifts. You will be more cranky, less motivated, more emotionally labile, and more tired. Try not to schedule an important interview or a test for at least 48 hours post night shift. Understanding that the physiological effects are inevitable helps me cope with them when they come. If I forget and start blaming myself for a self-perceived failure in some aspect of my life, Jamie is pretty quick to remind me that I probably had a few late evenings or nights.
We are diurnal creatures. No matter how much you hack, how fancy your blue blockers are, or how many sleep apps you get, shift work will affect you. Don’t be an ostrich. Mitigation strategies are just that: they are not solutions. Why do you work shift? What’s your health cost to benefit ratio? Can you avoid it and still get the same benefit (career, money, recognition)? If you choose to do it – be aware of the consequences.
Below is my roster for last week. We always write a copy of my upcoming roster on the fridge every Sunday and plan our week around it. My primary job is in an urgent care clinic and also do a few hours at an immigration clinic most weeks. KF stands for Kung Fu, and S/C for strength and conditioning, a.k.a garage training.
They are what they are, not miracles. If you are not doing all the other stuff: food, sleep, movement, sunlight, they are a bandaid at most. That being said, there are a few hacks that I find useful.
- Blue blocking apps/software. If you have lived under a rock and still haven’t downloaded the software that blocks the blue light coming out of your device and hitting your retinas in the evening and telling your brain that it is daytime, you are crazy and should do this right now.
- Our good friends, Craig and Steph, introduced us to Gunnars, blue-blocking glasses I can actually wear at work. Most patients don’t notice the slightly yellow tint although I had one nerdy-looking guy nearly pee his pants with excitement when he realised his doctor was wearing “gamer’s glasses”.
- I don’t know anybody who loves alarm clocks, but this comes pretty close. Lumi is a silent alarm which slowly brightens up your room simulating sunrise. You wake up at some time during those 30 minutes, when your body is ready. It’s a sanity-saver in winter.
- I have 600mg of magnesium every night before going to bed. Some people find that certain forms of Mg give them vivid dreams. I always have vivid dreams and sometimes sleepwalk, and I don’t find any difference with Mg.
In my experience these are the worst offenders when it comes to disrupting sleep and circadian rhythm. I either avoid them altogether or proactively manage them. There are various levels of scientific evidence to support this. I suggest you find your own tolerance levels and how much you can get away with.
Alcohol. This is a biggie for me, and not in a “I cannot drink a bottle of wine anymore” kind of way. My tolerance for alcohol since starting shift work is practically non-existent. Alcohol severely disrupts my deep sleep (a precious commodity!), makes me more likely to act out my dreams (Jamie particularly dislikes it when I dream about Kung Fu because he gets punched or kneed in the middle of the night) and makes me irritable and anxious the following day. I don’t get depressed but my mood becomes very labile. I limit myself to 1 drink on special occasions. I do know many colleagues who drink in the evenings and – *gasp!* – drink when arriving home after midnight to “settle down”.
Coffee. I have my last coffee at least 8 hours before my projected bedtime. This makes it 2pm for day shifts, 4 pm for evening shifts and 10pm for night shifts. Overall though I keep my coffee consumption to 7am to 12pm with after night shift excepted obviously.
Screens. From personal experience, the negative effects of screens go like this: mobile phone > computer screen > TV screen. I can manage mobile phone exposure pretty well before bedtime. Unfortunately I am stuck in front of computer screen at work at all hours of day and night. As I have mentioned before, Gunnars do a little bit to help out.
Artificial lighting. I found this a big problem. I am not sure whether it is the artificial lighting per se, or the lack of natural light, or both. It has a particularly prominent effect when I work a regular day shift and have to stay inside the clinic all day. It makes my eyes tired and vision blurry. In my opinion, this is one of the major reasons why I tolerate evening shifts better than days: when I have an evening shift I spend a huge chunk of my day either outside or inside our apartment which is flooded with natural light during the day. My alertness during the evening shift day lasts from 9am to 11pm easily, with a short 20 mins nap around 3pm. My alertness during the day shift is probably limited to 9am to 1pm with another short spike from 4pm to 6pm. Unfortunately, I am limited to a 30 minute lunch which I have to take inside the clinic. For those of you who are able to get out during the day, cherish that opportunity.
Stress. Gone are the days when I would feverishly type a witty response to someone who was wrong on the Internet and stay up way past my bed time. Being older and wiser, my ZFG levels are on “full-to-near full” most of the time. The events which most likely wind me up are difficult situations at work and personal relationships, rather than chimeric Interwebz battles with people I don’t know or don’t care about it. I know, it’s hard to avoid but starting a fight with a significant other before bed is pretty much a sleep-killer for everyone involved. Either resolve it, or leave it in the morning, don’t go to bed angry. In terms of managing work stress, biking home at the end of the shift is practically meditation and helps me shut down my work brain while also avoiding behind-the-wheel road rage.
In Part II I will give a glimpse of my totally non-glamourous shift work life and share a breakdown of what I do during my day shift, evening shift and night shift.
A few helpful articles below:
3 Simple Ways to Improve Your Sleep Before Lunch by Jamie Scott
5 Things You Can Do After Lunch to Improve Sleep Quality by Jamie Scott
Artificial Light Regulates Fat Mass: No bueno by Bill Lagakos
How a Week of Camping Resets Your Body Clock by The Conversation (based on Wright et al)