RHR: How Shift Work Impacts Your Health—and What to Do about It

Shift work is a really interesting topic.  I talked about it a little bit in my book, and it’s something that there’s a growing awareness of, thankfully.  Twenty percent now of the industrialized population around the world works beyond normal hours in various types of shift work or flexible work.  The days of just 9-to-5 work for everybody, if those days ever existed, are definitely gone, and this kind of shift work or flex-scheduling work is becoming increasingly common.

In this episode, we cover:

5: 28  How shift work impacts your health
16:52  How to mitigate the effects of shift work
25:32  How to schedule your day off

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Full Text Transcript:

Steve Wright:  Hey, everyone.  Welcome to another episode of the Revolution Health Radio Show.  This show is brought to you by ChrisKresser.com.  I’m your host, Steve Wright from SCDlifestyle.com, and with me is integrative medical practitioner, New York Times bestseller, and drinking coffee, Chris Kresser!

Chris Kresser:  It’s actually water, but I did have coffee this morning.  How’s it going, Steve?

Steve Wright:  Good.  I’m telecasting from my parents’ house in Michigan.

Chris Kresser:  Oh, right.  Cool.

Steve Wright:  And today’s a pretty special day for you, right?

Chris Kresser:  It’s my 40th birthday.

Steve Wright:  What?!

Chris Kresser:  The big 4-O.

Steve Wright:  Somebody better put, like, party stuff on the screen for this.

Chris Kresser:  Yeah, unfortunately it’s not feeling very festive.  I have a long day of work, which is great because I love my work, but we celebrated last weekend and had some people over to the house for a barbecue.  And then this weekend we rented a house in Tomales, which is a sweet little town up the coast.  We’re going to go to the beach and hike and just hang around.  So today is just another day.

Steve Wright:  Well, congratulations.  Happy birthday, Chris.

Chris Kresser:  Thank you.

Steve Wright:  And I’ll say it for every listener and reader and everybody else that you’ve influenced, so thank you.

Chris Kresser:  All right.

Steve Wright:  Yeah, so we’re doing the new format again today.  We have our recorded SpeakPipe question.  But before we get into that, we had kind of a tradition going, and that was talking about your breakfast, Chris.  It sounds like you started with some coffee, but there was probably other food mixed in there, wasn’t there.

Chris Kresser:  Actually, not today.  I was really busy, and it was my turn to take Sylvie to preschool this morning, and I had a bunch of stuff to do, so I just had coffee and cream and that was my breakfast.  A little intermittent fasting today.

Steve Wright:  Awesome.  Very cool.

All right, well, before we get into our question and play it, I just want to let everybody know that Chris has redone his website.  If you haven’t been back to it lately, you need to get over there.  It is a little simpler to navigate, and what he’s done is he’s also made his 63-page 9 Steps to Perfect Health eBook available again for you.  If you go to ChrisKresser.com, right there in the middle of your browser you’ll see the 9 Steps to Perfect Health eBook.  It has a ton of info about nine different steps.  You couple probably work on one of these steps every month throughout the rest of the year into the new year, and before you know it, you’d be changing your life and your health and those around you.  Go to ChrisKresser.com and get that eBook if you haven’t yet.  There’s a ton of Chris’ best tips, tricks, and lifestyle changes that could really turn your health around and set you up to live your best life possible, so check that out.

Chris Kresser:  All right, so we’re going to play the question for this week.

Question from James:  Hi, Chris.  My name is James.  My wife and I both work overnight shifts, myself as a firefighter and her as a mental health worker.  I was wondering what we can do before, during, and after to help us get through the night and to lessen the effects of working on a night shift.

Chris Kresser:  OK, so as you can see – or as you can hear, actually – James is wondering how to mitigate the potentially harmful effects of doing shift work.  This is a really interesting topic.  I talked about it a little bit in my book, and it’s something that there’s a growing awareness of, thankfully.  Twenty percent now of the industrialized population around the world works beyond normal hours in various types of shift work or flexible work.  The days of just 9-to-5 work for everybody, if those days ever existed, are definitely gone, and this kind of shift work or flex-scheduling work is becoming increasingly common.  In the US, about 9 or 10 million people perform shift work, and that doesn’t even include the flexible scheduling stuff that I just mentioned.  And if you think about it, there are a ton of professions that pretty much require this type of work, everything from medical professionals, so doctors, nurses, healthcare workers of all types, police, fire, financial professionals like stockbrokers and accountants, hospitality, so waiters, bartenders, people in the entertainment world like performers, DJs, the media, of course, manufacturing jobs, retail, and people who work in travel like pilots, flight personnel, people like that.  I’m sure everybody listening to this show knows somebody who is doing shift work, or perhaps you do it yourself.  The problem is that an increasing body of research has made it pretty clear that shift work can have a profound impact on our health, and it does that in two ways.  The first is lifestyle, and the second is biology.

How Shift Work Impacts Your Health

In terms of lifestyle, working long hours makes it harder to exercise regularly.  You’re probably more likely to eat irregular meals or eat less healthy meals.  We know that sleep deprivation and changes in sleep patterns can affect food cravings, so if you haven’t slept well the night before, your judgment around food is likely to be impaired.  That’s probably the best way to put it.  You’re more likely to reach for foods that you wouldn’t eat otherwise if you were sleeping well.  And then you have the effects of social isolation that can be significant with shift work.  If you’re sleeping during the day when all your friends are out spending time together and then you’re awake at night when they’re asleep, that can be problematic, and it can make it difficult because you’re essentially on a different schedule than everybody else.

Steve Wright:  Yeah, that’s a big one.  I did some shift work back when I was in the manufacturing industry.  I did second-shift and third-shift work, and it is so hard to have that energy to get to the gym when you’re off the normal schedule, and at least for me, it felt like I had to choose between social interaction and maybe some sort of healthy behaviors.  It really seemed to crunch time in a weird way even though I know we all have the same 24-hour cycles.

Chris Kresser:  Yeah, and that’s not a great choice, right?  Social interaction is crucial for health, as we’ve talked about a lot, and exercise and diet are also crucial.  That’s what makes this so tricky.

The second factor is biology, and this means essentially that being awake at odd or irregular hours really messes with our circadian rhythm, which is the internal body clock that is keyed to natural daylight and darkness.  If you think about it, all life on earth – and we’re talking about since the beginning, the very, very first single-celled organisms billions of years ago – evolved in the natural cycle of daylight and darkness that we have on this planet.  I mean, that hasn’t changed in a very, very long time!  Every form of life that arose on this earth evolved in that cycle, and we were constrained to that cycle, every form of life was constrained to that cycle up until about 150 years ago when artificial light was invented.  Just let that sink in.  We basically lived in sync with the natural rhythms of light and dark for billions of years – I mean, we weren’t living as humans for billions of years, but all life on this planet for billions of years up until 150 years ago.  And with the invention of artificial light, for the first time we could actually shift so that we weren’t just sleeping with the darkness and waking with the light.  We could actually, with artificial light, stay up and work or do something else all night and then, of course, start sleeping during the day.

The problem here is that our physiology is designed to function in harmony with these natural light and dark cycles.  In fact, every cell of our body is affected by these cycles, and so when we’re exposed to light at the wrong times, like at night, or irregularly, our circadian rhythm is completely disrupted, and this can throw everything out of whack from the cardiovascular system to metabolism to digestion to immune function to endocrine and hormone balance – you name it.  Because every cell in the body is affected, then there’s no system of our body that’s not going to be affected.  This explains why shift work is associated with such a wide variety of problems.  Just to name a few, in the short term you see GI disturbances, increased risk of injuries and accidents, insomnia, decreased quality of life, changes in mood, general malaise, depression, etc.  But over the long term you see more significant issues like increase in cardiovascular disease, diabetes and metabolic problems, obesity, more serious gastrointestinal problems like inflammatory bowel disease, depression and mood changes, decrease in fertility, increase in cancer rates, and an increase in the overall risk of death.

Now, some of these problems develop quickly.  Like, blood sugar can be affected almost overnight.  We’ve seen some studies where just a single night of poor sleep can decrease insulin sensitivity the next day, so that can be almost immediate.  Then other changes develop more gradually over time.  It seems like the risk of cancer only starts to go up if you’ve been doing shift work for 15 or 20, although the jury is still kind of out on that.

Steve Wright:  So, Chris, if we kind of just take a step back because that’s a lot of doom and gloom there regarding some people who protect our society who do the firefighting and policeman jobs and some really important jobs out there, soldiers as well.  What about the fact that as hunter-gatherers somebody had to stay awake to protect the tribe?  You know, they probably didn’t have regulated shift work every night five days a week, but it seems like back in the day somebody would’ve had to stay awake for most of our evolution to at least alert if the lions were hungry.

Chris Kresser:  I’m not sure if that’s totally true.  I think in hunter-gatherer societies, what you see is a more biphasic sleep pattern, which means they go to bed early when the sun goes down and there’s not a lot to do at night, so they might sleep from, like, 8 or 9 to midnight, and then they might wake up and be just kind of awake for a couple hours.  Then they might go back to sleep again.  And because they were sleeping outdoors and because of this biphasic or multiphasic sleep pattern, it’s probable that there was somebody awake at any given time during the night, and that served a protective function, but I doubt they had people that were working shifts that were staying up all night.  I don’t think that’s ever been observed in hunter-gatherer culture.

It’s tough.  I mean, there’s no doubt that shift work is associated with these problems, and I think we just need to be honest about that so that we can then take whatever steps we can to mitigate those potentially harmful effects.  And then also at a public policy level there are some important things that companies and governments can do to lessen the impact of shift work, and we’re going to talk about that in a second.

Steve Wright:  Yeah, if the hunter-gatherers did have that kind of philosophy around the way they lived, they had everything else dialed in.  They were walking around earthing all day, they were in the sun all day, they weren’t eating grains because they were moving a lot typically – they had pretty much the rest of their health dialed in, so maybe even if they did adopt some different sort of sleep patterns, that might have protected them against the shift.

Chris Kresser:  Yeah, no doubt.  Just to give a few examples here to finish up the gloom-and-doom segment before we go on – and the reason again that I’m sharing this is not to freak people out but just to communicate what the research shows and hopefully make the need for some of the suggestions that I’m going to make as clear as possible – rates of prostate and breast cancer tend to be about 40% to 70% higher in male and female shift workers, shift work has been shown to raise the risk of cardiovascular disease by about 40%, and one study found that the risk of stroke increases by about 5% for every year that somebody does shift work, but that only happens after 15 to 20 years of shift work.  Then one Japanese study found that shift workers had about a 50% higher incidence of diabetes than day workers.

Interestingly enough, these changes appear to have different effects depending on the person’s chronotype.  Chronotype means your natural pattern of sleeping and waking.  Some people naturally go to bed earlier and wake up earlier, some people naturally go to bed later and wake up later, and the people who naturally go to bed later and wake up later are more affected by shift work, especially the night shift, than people who have the early chronotype.  That’s some new research that’s recently become available.

Steve Wright:  So did you say that people who naturally go to bed later are more harmed by working later into the night?

Chris Kresser:  Yeah, basically.  They’re more harmed by the night shift, according to the research that we have.  You’d think it would be the other way around, but it has to do with the waking more than when they go to sleep.

A lot of these problems are mediated by changes in melatonin secretion.  Melatonin is a hormone that regulates our sleep-wake cycle.  It also is responsible for the feeling of sleep onset.  Like, as you get tired after the sun goes down, that’s melatonin levels rising.  Melatonin should be low during the day and high at night, and one of the problems with shift work is that when you get exposed to light, that decreases melatonin secretion and increases cortisol secretion.  So let’s say you sleep during the day at a time when cortisol levels should be higher and melatonin is lower, and then just as your melatonin levels start to rise at night, you are going to work in a brightly lit environment, and that will suppress melatonin levels.  So overall, because you’re sleeping in a dark room during the day and then you’re exposed to bright light at night, your melatonin production is going to shift and it may be lower overall than it would have been otherwise, and changes in melatonin secretion are thought to be involved or contribute to a lot of these issues that we’re discussing, particularly cancer.

OK, so enough of that.  I think everybody understands what the risk is.  I think James, who asked the question, obviously understands.  Otherwise, he wouldn’t have asked the question.  So let’s talk a little bit about what we can do to mitigate some of these potentially harmful effects.

How to Mitigate the Effects of Shift Work

The first thing – and in some ways the most important – is also something that you may not necessarily have control over, which is a bummer, but hopefully an increasing amount of research is going to shift this within private companies and public government institutions as well.  We know that working a regular shift where your shift is the same every day is way less harmful than when you’re on a rotating shift where, let’s say, you do two night shifts or three night shifts in a week and then you have three day shifts and even worse where that changes every week, so you’re on a constantly rotating shift.  The reason a lot of companies do it that way is out of a desire to be fair so somebody’s not working the night shift all the time or the day shift all the time, and while that kind of makes sense on a certain level, when you understand the research and the physiology behind this, it actually doesn’t make sense because there’s some evidence that you can adapt to a constant shift over time and your body does everything it can to mitigate some of these harmful effects that we talked about, but when you’re on a constantly changing shift, your body really can’t adapt to that.  That’s probably the biggest thing that people who are shift work should be advocating for if at all possible in their job, and I know that it isn’t always.  Then, as I said, on a public policy and company policy level, I think as the research gets out there more – and there’s a ton of research on this, and there are even some nonprofit organizations, advocacy groups that are working to raise awareness about that – we’ll see a shift, hopefully.

The next thing is diet and exercise.  Of course, this is obvious that we should all be paying attention to our diet and exercise, but it’s even more important for people who are doing shift work because as we said in the beginning, it’s really easy when you’re not sleeping regular hours to fall off the wagon, so to speak, and start eating convenience foods or junk foods or just not staying as on target with the diet as you might be otherwise.  This means doing a lot of planning and preparation in advance, maybe getting some help if that’s possible and necessary, preparing your food and taking it to work with you, spending some time during the week preparing large meals in advance that you can freeze and then just take out of the freezer and bring with you to work.

Exercise is really, really crucial, and in particular, the timing of exercise may make a difference.  Sometimes people want to exercise right after their shift and before they go to bed, and that may work if you’re not really exhausted after your shift, but if you feel really wreaked and worn down after your shift, it may not be a good idea to exercise right afterwards.  And if you find that exercise kind of stimulates you and makes it harder for you to go to sleep, it would be better to go to sleep first and then exercise later.

Sleep and sleep hygiene are crucial, again, for everybody but particularly for shift workers.  When you look at the scientific literature, there are actually some papers that talk about how to mitigate the effects of shift work and jet lag for flight personnel and things like that, and all of the papers, without fail, talk about not only sleep hygiene, but particularly artificial light control or just general light control.  For example, when you’re sleeping, you should be sleeping in a very dark room, as dark as possible, during the day especially, because you want your body to get the sign that it’s night, and that’s possible now with blackout shades or putting foil on your windows and just making your sleeping environment as dark as possible, getting rid of any devices that emit light or beeps or any other kind of thing that could distract you, sleeping in a cool room, and even using a facemask on top of all that and earplugs can really help to create a distraction-free environment and one that’s conducive to sleep.

Another tip is when you leave work, assuming it’s light, put on some amber-tinted glasses, and you can get these from Amazon and some other places.  These amber-tinted glasses filter out blue wavelengths of light, which is the type of light that suppresses melatonin.  Right when you leave work, you put these on, and on the way home, it’s already sort of telling your body that nighttime is approaching even if it’s not so that when you get home you’ll be more prepared to go to sleep.  On the other side of that, right when you wake up, even if it’s night, you should get some exposure to bright light, and if it’s nighttime one of the ways you can do that is to get a light machine.  These are used for seasonal affective disorder, like phototherapy.  Get a bright light machine, sit in front of that for 15 or 20 minutes while you’re getting ready to go to work, or you can install much brighter LED kind of lighting in your home and bring up the lights to full power so that you’re kind of training your body or telling your body that it’s daytime and to start increasing the cortisol levels.

Steve Wright:  Yeah, just from my experiences working second and third shifts, everybody hits that life factor where in regular shift work you can run to Chipotle or whatever whole food you have near you or whatever go-to source, but for these people, nobody else is working at those hours of the night, so having EPIC Bars or whatever your go-to nut source or snack is or the frozen meals you mentioned at work, I think, is a huge, huge must for these people, in my experience.  Then that earplugs thing and unplugging and turning off your phone device, I think, is huge.  That’s when I started wearing earplugs back in college when I was doing shift work, and I’ve been doing it ever since because it’s the only way I could sleep back then.

Chris Kresser:  Yeah.  It’s all about creating that cool, dark cave, which is helpful at night for sure, but it’s even more crucial during the day.  I know Michelle Tam from Nom Nom Paleo, she works night shifts at a hospital, and she always brings her foods in these little LunchBots stainless steel containers, which are fantastic.  I love them.  Doing that may sound like another thing to do during your time off, but it’ll really make a big difference.

Another thing in addition to the light control that is generally recommended is to avoid stimulants.  It may seem natural to drink coffee at the beginning of a night shift to keep you up all night, but that is often problematic because it just further kind of tweaks the rhythm, and if you do some of the things we’re talking about with light control and sleep hygiene and diet and exercise, your body should begin to adjust to that, especially if you’re on a regular shift over time, to the point where you don’t need stimulants or you don’t use them a lot.  Maybe a single cup of coffee rather than a quadruple latte or something like that would be fine.

Steve Wright:  What about food timing?  I know that when I was working third shift, for instance, I’d come home and eat a massive meal and it would just put me to sleep and it was part of my ritual to go to bed.  Nowadays if I eat a big meal and then go to bed, sometimes I can get GI discomfort, but that was part of the ritual for me to get to bed back in the day.

Chris Kresser:  Yeah, I think it depends on the person and their goals.  If people are trying to lose weight, that may not be the best idea.  If they have GI stuff, it may be better to eat a smaller meal and then eat again when they wake up.  I think you just really have to experiment there and make a decision based on your own personal needs and responses.

How to Schedule Your Day Off

There’s often a question about what to do on days off, right?  When you look at the research, it’s pretty clear that the optimal thing to do on days off would be to maintain the same schedule that you have when you’re working, but that’s pretty impractical for most people.  I mean, it’s hard enough to work the night shift as it is because you’re on a completely different schedule than all of your friends and other family members, etc., so then to keep that schedule on your days off is pretty difficult.  So some researchers have proposed a kind of hybrid model where on the days off your sleep should start about 5-1/2 or 6 hours earlier than it would typically start on the workday so you’re not fully shifting back to a daytime schedule but you’re shifting kind of part of the way.  And you still use the exposing yourself to light right when you wake up and creating a dark environment and wearing the amber glasses before you go to bed tips that I mentioned earlier so that your phase shift, the shift of the circadian clock, doesn’t go too far back in the other direction towards the day shift on those days off.  That’s been proposed as a kind of meeting point for people where they can still interact with other people who are not working the night shift and with family members and friends and things like that but without totally getting off track and having to start the adaptation process over again when they go back.

Steve Wright:  Not to be a super buzzkill on top of all this other buzzkilling information, but wouldn’t the days not to mess up your diet and lifestyle be those off-days when you’re switching from the off shift into a regular shift or a phase shift?  Because that would be like the jet lag scenario where you’re crossing time zones and kind of messing with your sleep cycle one way or the other and increasing your insulin resistance and things like that.  Am I on top of something there or am I way off base?

Chris Kresser:  Say it a different way.  I don’t understand your question.

Steve Wright:  For instance, I’ve seen some studies and heard some people speak on the fact that just phase shifting for jet lag across multiple time zones will start to harm insulin resistance and start to mess with our clocks in the same way we’re talking about right now.

Chris Kresser:  Mm-hmm.

Steve Wright:  So if I’m becoming accustomed to a night shift work schedule, on my days off if I go back to a day shift and that day shift is when I get to hang out with my friends or my loved ones and it’s much easier to, again, partake in maybe some non-paleo-approved fun activities, those would actually be the days where your hormones might be even more out of whack and they would be the worst for you to stray.

Chris Kresser:  Yeah, that’s right.  It’s also, as I said just now, that the hybrid thing is probably a good idea so you’re not going right from working night shift to staying up the next day all day long.  You’re modulating it a little bit so it’s kind of a hybrid for those couple days that you have off so it’s not such a dramatic change and you don’t have such a huge hormonal shift.  Then, yeah, as you’re saying, Steve, it’s really important that you stick to good habits on those days in particular.

I wish there was a way that I could just wave a magic wand and protect everybody from the potential harms here because, as Steve said, these are some of the most important professions:  medical workers, police, fire, military, etc.  It’s crucial work and it needs to be done, and people who are doing it, it’s admirable.  Hopefully all of these things that we’ve talked about can make a big difference in how your body responds.  The other thing to keep in mind is that a lot of these studies were just people who were probably eating a crappy diet and not following these sleep hygiene tips and not exercising regularly and not doing all the things that we always talk about, so it stands to reason that most people listening to this who are doing a better job of that are already going to be at lower risk before you even implement these tips, and then after you put these tips into practice, I’d imagine the risk would drop even more.

Steve Wright:  Yeah, and the other thing to throw in there that I think we should mention is stress because all of these professions are already higher than average stress and then you put that on top of the phase shifting.  So these people, I would stand to reckon, would benefit even more from some sort of meditation practice or their stress-reduction practice of choice.

Chris Kresser:  Absolutely.  Great point.

All right, so that’s it for this week.  Please remember to submit your questions via SpeakPipe, your recorded question.  That’s ChrisKresser.com/PodcastQuestion.  We’d love to hear from you.  As you can see, this new format is pretty much entirely driven by your questions, so make sure to leave one for us there, and we’ll talk to you next week.

Steve Wright:  Yeah, and make sure everybody wishes Chris a happy birthday!  Go have fun, Chris, and reduce your stress as well.  In between episodes, make sure you follow Chris over at Facebook.com/ChrisKresserLAc and Twitter.com/ChrisKresser.  That’s where he posts a lot of different studies and newsworthy articles that we might end up talking about a couple weeks later on the podcast, so if you want first dibs, go there.