UA researcher studies shift workers and how disrupted sleep can harm their health

Kat Kennedy is a post-doctoral researcher who studies sleep — specifically circadian rhythms, and what happens when they’re disturbed. For office workers, maybe that means the odd late night or early morning.

But Kennedy is particularly interested in the sleep patterns of shift workers — people who work in fields like food service, long haul trucking and nursing. These workers tend to have schedules that make it hard to get enough sleep, or consistent sleep, and Kennedy’s research at the University of Arizona’s BIO5 Institute focuses on what these disruptions mean for their health.

Kennedy spoke with The Show more about it.

Emily Gervais

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Handout

Full conversation

KAT KENNEDY: We know that when we try and force sleep, at a time when our bodies are not set up to be sleeping well, thinking here of the person who's, let's say, trying to sleep during the day so that they can be on the night shift, we know that their sleep tends to be impaired just because there's a mismatch between their biological drive and what the behavior is that they're trying to do.

So they have a biological drive to be awake because it's the daytime. But they're trying to engage in this sleep behavior because they have to be up at night to be working.

SAM DINGMAN: Well, tell us a little bit about some of the issues that shift workers encounter that correspond to difficult sleeping circumstances.

KENNEDY: What we seem to see is that for people who are experiencing shift work, especially these kind of rotating shifts where their body's not really able to adjust to any type of schedule, we tend to see that there are worse health outcomes in a lot of these people.

I like to say this with sort of like the caveat that there's no need to assume the very worst if you are shift work right now, because there's lots of things that you I'm happy to talk about this, lots of things that you can do to help yourself.

But we do sort of see worse health outcomes for a lot of these people just because these body clocks, these clocks that we have in virtually every single cell in our bodies, really dictate basically everything that the body does.

DINGMAN: Right, right. And this can be something as simple, if I'm not mistaken, as driving home after working an overnight shift. You're physically exhausted, but the sun is rising. And so, and you've been up all night. Your body is telling you that it's time to sleep, but your body is also receiving signals from the environment that the day is just beginning.

KENNEDY: Right. That's exactly it. Because if you're working during the day and then you're unwinding after work, it's getting darker. The sun has set. Even in extreme latitudes where there's longer days, you still eventually experience this period of darkness before bed or before you're going to sleep.

And that's really important because people have heard of melatonin. Melatonin is a really important signal for our brains that says, “it's nighttime.” And it serves as this really important antioxidant that gets to work in our bodies while we're sleeping.

DINGMAN: As I understand it, some of the health outcomes that shift workers are at higher risk for would be things like weight gain, appetite loss, mood disorders, loneliness, which I thought was an interesting one.

KENNEDY: Right, that's correct. So yeah, we definitely see a higher risk of different cardiometabolic disorders. So this could be things like weight gain, insulin resistance, Type 2 diabetes, things like this. We see things like irritable bowel syndrome, which is reported quite commonly.

And this tends to be worse among people who are on rotating shifts, because essentially you're trying to eat when your body is not really primed for food because let's say you've just switched from a different shift schedule the day before. During that shift schedule you're eating at a completely different time and your body's like, hey, this wasn't the time we ate yesterday. I'm not necessarily set up to be eating right now. So that can lead to sort of some gastrointestinal issues.

But the loneliness one, yeah, it's something that I've heard many people sort of anecdotally as I've spoken to people over the years. I've heard many people discuss that it can be really challenging if you have a, you know, the family members, your partner, your spouse, things like that, on a completely different shift to you because you're having to say no to things. You're having to say no to social, you know, various different social opportunities because you might be working or you're really trying to recover before you switch to the night shift the next day. And so there's sort of that extra time that's needed to recuperate.

So it's really just some missed opportunities sometimes that can come.

DINGMAN: Right. So this gets into what you were alluding to earlier, the idea that if someone is listening to this and is a shift worker and getting alarmed, which would be understandable, there are ways to counteract some of the deleterious effects of shift work on sleep that you are able to share.

One of those is finding a consistent sleep schedule, right? Even if it's not the same sleep schedule that others might keep to.

KENNEDY: That's right. Your consistency in your sleep timing is associated with better health across the board. So that's something that's really important to keep in mind. The general recommendation right now for people who do have shifts that chop and change, which might be unavoidable for you if you're a rotating nurse, for example, is to at least try and have half of your sleep episode, so most of us aiming for between seven and nine hours of sleep per night, try and have at least half of that, so three and a half, four, four hours, something like that, that is overlapping between all of your shifts.

So as best as possible, try and have what we'd consider to be like these anchor hours, of say four hours, that don't change no matter what shift you're on. And that just has a way of kind of tethering us to some amount of routine, even if our shifts are changing a lot around that.

DINGMAN: So this gets tricky though, right? Because shift work positions are often associated with not as much flexibility, right, in terms of how much control workers have over their schedules and things like that.

KENNEDY: That's right. And this is where it really is down to the employer. And a question that I think about a lot is, who is responsible for shift work to begin with? Who can take responsibility for it?

It's something that we all as a society, I think, take for granted, especially when we think of all these essential services that are available around the clock, whether that's first responders who will help us in a crisis, to even things like picking up your coffee at six, seven in the morning, there's a barista who's had to be up a couple hours before that.

We all take, I think, a lot of these services for granted. It's so normal in this 24-7 society that we have, that it begs the question, who is responsible?

DINGMAN: I know that some of that overlaps with other work that you've done on sleep insofar as it affects women's bodies, right? And a lot of shift workers, I mean, we've mentioned nurses a few times, are women. And it seems like female nurses are sort of in double jeopardy there.

KENNEDY: That's right. You know, women's sleep health is a largely understudied area, as is shift work. And the issue, so the reason that shift work is understudied is just because it's a really difficult population to get to participate in research studies.

You know, these are often really high stress roles. And the women especially, you know, I do a lot of women's health research and women have largely been left out of biomedical research for most of history. And so we're playing catch up across the board now in terms of having to include a female, whether it's animals in animal studies or humans in human participant research.

And it's really critical because not only because we have females filling these shift work roles, but because females experience many changes across the lifespan, right? So there's the kind of premenopausal years when many females are experiencing menstrual cycles, meaning completely different hormonal changes across the month. They might be using hormonal contraceptives, which I'm particularly interested in, which again completely change the hormonal milieu in the body. Then there's things like pregnancy and postpartum. There's things like the menopause transition.

So there are all of these really massive changes that happen in women's health across the lifespan. I think it's really important to be giving attention to women especially and some of the unique ways that they might be a bit more vulnerable.