Program: Chronotypes: early birds vs night owls

Tegan Taylor: Norman, wake up, it's not nap time, okay? 

Norman Swan: Fine, it's not nap time. Oh, I have dribbled down my shirt…

Tegan Taylor: I wanted to ask you which of the following animals you most identified with, and no further clarification will be provided at this time; a lion, a bear, a wolf and a dolphin. Who do you feel like you align more closely with?

Norman Swan: I think I like the idea of a lion, I think it's just a bit more sophisticated and elegant.

Tegan Taylor: I think it's hard to go past lion…

Norman Swan: I think you could have a good chat with a lion. 

Tegan Taylor: It would have a good chat as it was biting your head off. 

Norman Swan: So what about you? Well, you know why you're asking the question, you're biased.

Tegan Taylor: This is it, I'm the woman who knows too much here. Basically it has to do with something called your chronotype, that is what time of day you feel you're most productive, because that is what we are talking about today on What's That Rash?.

Norman Swan: That's the podcast where we answer the health questions that everyone's asking.

Tegan Taylor: And this week's question comes from Kerry, who says, 'Hi, Tegan and Norman, love the podcast.' Love you, Kerry. Kerry says, 'I've always been a person who enjoys sleep, and I find sleeping in to be one of life's simple pleasures. On average I like to get nine to ten hours per night. I'm wondering,' Kerry asks, 'if we are hard-wired to be either an early bird or a night owl, or both, or neither in my case, and if so, can this be changed?' Great question, Kerry. I love talking about sleep. 

Norman Swan: And do you want to just explain the animal thing that we got into there so we can just break that out before we answer Kerry's question?

Tegan Taylor: Okay, we'll get into a lot of science today. I know this is a chronotype breakdown developed by a researcher, but I don't really know how evidence based the animal equivalents are. So basically lions wake up early, they're diligent and most productive in the morning. They tend to wake up around 6am, they're most productive 9pm to 2pm and they like to go to bed around 10pm on average. Bears are most common, 55% of the population apparently are bears.

Norman Swan: So they sleep in winter. 

Tegan Taylor: They sleep all winter long. No, they basically just follow the sun. They wake up in the morning, they are productive in the middle of the day, and they go to bed at night. It's not very special to be a bear. A wolf is what we would probably consider to be a night owl. They'll wake up a little later in the morning, they're most productive in the afternoon, and they like to go to bed late. And then a dolphin…and I think this is based on…you know that little factoid that dolphins are never fully sleep, like only half of their brain is ever asleep at once. Dolphins are like insomniacs, pretty much, most productive in the afternoon, but fragmented sleep, irregular sleep schedule, but at least they are really smart and very smooth, I suppose. 

Norman Swan: Yeah, you get that impression, don't you.

Tegan Taylor: So now that I've told you what each of the animals are, do you change your…?

Norman Swan: No, I think I'm still…

Tegan Taylor: Still a lion.

Norman Swan: I'm biphasic. 

Tegan Taylor: Okay. What do you mean by that? 

Norman Swan: Well, I really get a lot of work done early in the morning…

Tegan Taylor: Very early in the morning, like 3am. I've received the texts, so everyone already knows this about you.

Norman Swan: It's true that's more my insomnia, that I wake up for an hour or two, then I go back to sleep again. But I am at my most productive in the morning, but then after a little nap in the afternoon, I power through in the evening, I get a lot of work done in the evening too. 

Tegan Taylor: That feels very dolphin-y to me, but this isn't really what this show is meant to be about. Do you know, when we got this question from Kerry, I was, like, we've done this before, but no, we haven't done this before. We have done nap times. Can you train yourself to sleep less? We've done a story on melatonin. We did a rapid-fire round on sleep, all in the last year or so. Definitely check out the deep and rich What's That Rash? sleep archives. But we haven't done chronotypes before, and I'm really excited to get into it. 

Norman Swan: We have on our sister podcast, the Health Report, and we'll put a link to that. But that predates What's That Rash? by a long way. It predates Coronacast, that's how old that one is. 

Tegan Taylor: That's the ancient archives. 

Norman Swan: I can't remember anything before Coronacast. But let's get into it. 

Tegan Taylor: Let's get into it. Well, I think what we could probably do…we don't usually do this, we usually like to delay the gratification a bit, but I think we can fairly summarily say yes, Kerry, yes, some people are hard-wired to be early birds or night owls, and some are both or neither. Am I right in thinking, Norman, we can kind of put that out there?

Norman Swan: Yeah, chronotypes have a strong genetic element, particularly what they call advanced phase chronotypes. So advanced phase chronotypes is, if you like, an extreme version of the lark, where you wake up earlyish in the morning and you're most productive in the morning, and then like to go to bed early. Now, there are people who have a more extreme form of that advanced sleep phase, where they're waking up at three or four o'clock in the morning, and they're really zinging at that point, and then they really clap out about six o'clock, seven o'clock in the evening. And the genetics of that are fairly strong. Some researchers believe it might even be autosomal dominant. 

Tegan Taylor: Oh, like genetically dominant?

Norman Swan: There's a one in two chance that if your parent had that advanced sleep phase, that you've got it too, but it certainly runs in families, and I think the genetic contribution weakens a little bit as you move into a more normal wake time, but there are still genetic elements to it. 

Tegan Taylor: It follows pretty much a normal distribution across the population, as far as I can tell. And you know that I love talking about evolutionary biology.

Norman Swan: Well, there is some evolutionary biology here behind chronotypes that would explain them being more evenly spread, and it's called the sentinel effect. 

Tegan Taylor: Yeah, this idea that probably someone's awake at whatever time it is of the day or night, because some people are morning people, some people are evening people, and so on. And that in your tribe, or your collection of humans that are living in the environment that humans lived in for most of human existence, which was a hunter-gatherer lifestyle…

Norman Swan: With no artificial light.

Tegan Taylor: Exactly, but also with fewer artificial time restrictions on us. So even before artificial light we had industrialisation, and we had agriculture, and we had times around things we needed to do, humans' natural habitat is actually much more like most animals, where it's a little more freewheeling. Anyway, there are still groups of humans that live in a very similar way to that hunter-gatherer lifestyle that we all lived more than 10,000 years ago. And there's a particular group of hunter-gatherers in Tanzania, the Hadza, that have been subject to these sorts of studies. And one of the studies that was done a few years ago was a sleep study, and they looked at basically people's sleep patterns across the group and across, I think, 20 days of observation. Only 18 minutes of the entire 20 days saw all of the subjects simultaneously scored as asleep. Across the 20 days, a median of eight people was awake at any given time period, or were in light stages of sleep. So at any given time, if some sort of predator or something like that was coming towards the humans, there was always going to be someone awake to rouse them, and they didn't organise it, it was just naturally occurring. 

Norman Swan: It wasn't like being on watch on a boat, it was just the natural variation within the population within that community had them awake at various times, which is why there's this even spread, although there are some people who have extreme versions of it, which can be very disruptive to their lives. But in answer to Kerry's first question, there is a genetic element here. The environment does have an influence. And when we get down to it, you can actually change your environment and change your chronotype a little bit.

Tegan Taylor: And it changes across your lifespan as well.

Norman Swan: That's right. So, as you get older, the tendency (again, this your reservation here, Tegan, always to say this is as an average and there are lots of exceptions) is to advance your sleep phase. And when you say 'advance', it sounds as if it's going to be later, but in fact it's earlier. So the earlier you wake up, the more important morning is to you in terms of productivity. And so there's a certain advance with every 10 years of ageing or getting on in life, and so older people tend to prefer mornings and going to bed a little bit earlier because their sleep phase has been affected. But it doesn't mean to say it can't be changed.

Tegan Taylor: So the thing I'd like to then explore, if we know that it's natural for there to be a span across the population, that some people are naturally early birds, some people are naturally night owls, just go with it, it's biology. We really (to borrow on your animal) lionise this idea of the early bird, the sort of morality of being an early riser. There's 'the early bird catches the worm', which is apparently from the 1600s. Have you seen this 'my five to nine before my nine to five' thing, Norman?

Norman Swan: No.

Tegan Taylor: It's a TikTok thing, I thought you were all over it. 

Norman Swan: I'm over TikTok, if that's what you mean, I'm not all over it. 

Tegan Taylor: Have you heard of rise and grind? 

Norman Swan: No…it sounds rude.

Tegan Taylor: I mean, it could be, depending on what you'd count as being productive. Anyway, the idea is that people are kind of showing off their hyper-productive lifestyles on social media. 'My five to nine before my nine to five' is like my early morning routine, my get up at 5am, drink my green juice, meditate, journal, do a workout, walk the dog, meal prep, and then I start work at nine and do my nine to five. It's this sense that if you're getting up, you're sort of like owning the day, owning the morning, you're being ultra productive. There are also people on TikTok or whatever, talking about their 5pm to 9pm but I don't think it has the same cultural resonance as this early morning…

Norman Swan: Not the moral certitude. 

Tegan Taylor: Yes, exactly. 

Norman Swan: So that goes back a long way, the idea that there's some superiority, both morally, ethically and in terms of productivity, of the person who gets up early and starts working early and is hugely productive. And there's a little bit of evidence that if you are a lark and you wake up early, you are more productive on average during the day than somebody who gets up later. But the reality is delayed phase people (in other words, owls) are very productive in the period after they wake up and get going as well. It's just might be three or four hours later than other people, and you might be more productive into the evening. And so there is this kind of moral superiority over the lark, over the person who gets up early, which is only slightly justified by the evidence. Basically, if you're an owl, your effort is a little bit later and probably just not recognised by the people who guarded our morals centuries ago, and they certainly didn't want you grinding first thing in the morning, I can tell you.

Tegan Taylor: No, no, the moral thing is super, super interesting, because I saw a study talking about this idea of, like, morality and early bird, and there is an association between early birdness or morningness and going to church and being spiritual or whatever, there's research into this. But one particular study that stood out to me was one that showed that early birds are more moral in the morning and less ethical at night. 

Norman Swan: Oh, that was that great study of cheating. 

Tegan Taylor: Yes, yes. 

Norman Swan: They got people playing games, and they had the opportunity to cheat. And if you only studied the morning, you'd think that larks were really moral people, but as the day went on, they became more and more crooked.

Tegan Taylor: And vice versa. So the night owls were cheating worse in the morning but they were more moral at night. I think this is so interesting.

Norman Swan: So we're not going to condemn the owls in this episode of What's That Rash?. You know, there are issues with chronotypes and mental health problems, mental health issues or developmental issues. So people with ADHD tend to be later risers, later to bed. There is some evidence that chronotherapy, in other words trying to move your chronotype to an earlier, more normal time of day, or usual time of day, does help people with ADHD. People with depression can wake up during the night, sleep a little bit later in the morning, or wake up early and be up early and be forced into a lark type situation. People with depression suffer a lot of sleep disruption in general, So it's hard to generalise about chronotypes.

Tegan Taylor: I feel like the thing with this story is that there's sort of three competing clocks. There's your internal body clock, there's light and dark, the way that the day is, solar time, and then there's something called social time, which is the time of day that clocks tell us that it is and all the activities that are associated with that, this idea that we have a shared understanding of when the day should start, when we should be eating meals, when should we should be going to sleep and leaving people alone, and that that really only fits one chunk of the population, and when there are discrepancies, especially on the social side of things, It can affect our health, our relationships, our work, everything.

Norman Swan: And of course we haven't even got into the influence of artificial light on this, that really does screw around with the day-night cycle. And there can be relationship issues. If you are an owl, particularly at the extreme end of owishness, or you're a lark, particularly at the extreme end of larkishness, and you are partnered with somebody who is…a lark has partnered with an owl and you're both at the extreme end, that does not go well for you, by and large, because unless your jobs match that, and you wouldn't be seeing each other anyway, one's on shift work or whatever, that can create relationship problems, because you're not able…coming to your social clock idea, your social clocks don't match. Mild differences in owlish and larkish chronotypes can be coped with, and that would be true of most couples, but when it's at the extreme end, it can be very difficult, and you probably do need to do something about it to get you more in sync with your partner.

Tegan Taylor: You reckon it should be questioned on the dating profiles? When you're sort of looking to match with someone, you should know what their chronotype is first. 

Norman Swan: Yeah, I'm sure it's much more helpful than a horoscope, I would have thought. 

Tegan Taylor: Actually, it's funny you say that, there is actually an episode on horoscopes on All in the Mind this week, made by What's That Rash? producer Shelby Traynor, so check that one out. 

Norman Swan: So instead of finding out whether you're an Aries, you know, find out what time you wake up in the morning. 

Tegan Taylor: Okay, so you said before you might not be able to change your chronotype, but you can shift your pattern a bit without kind of upsetting it too much. 

Norman Swan: I think there'll always be a sense, particularly if there's strong genetics involved, there's always a sense that you're running time. If you're by yourself, and you talk to people, when they say, 'My partner went on holiday for a couple of weeks and I was left home by myself, and I reverted to the way I was when I was an adolescent.' By the way, adolescents change their chronotype, as any parent of an adolescent knows, they move from an advanced sleep phase where a four-year-old or a three-year-old is waking up at five in the morning and you want to sleep for another two hours, and then when they're 12 and 13 or 14 years old, you can't get them up in the morning, and they're up late at night.

Tegan Taylor: And people tell you this when you've got little kids, and they're like, oh, one day you won't be able to get them out of bed. And I'm like, I can't wait for that day to come. But then it does come. 

Norman Swan: It does come, and you'll have wistful memories of the days when…

Tegan Taylor: When you were on time to school.

Norman Swan: That's right. So that changes, and then they settle back into their chronotype. So let's get on to what you can do to shift your chronotype.

Tegan Taylor: And with this, I have learned a very fun new word this week, the word is 'zeitgeber', which means like a time giver. Is this a word that you were familiar with before this week, Norman?

Norman Swan: Nein.

Tegan Taylor: Nein, indeed. So of course everyone knows 'zeitgeist' means the spirit of the time. Zeitgeber is basically things that tell your body about what time it is. The big one is light, obviously, the light-dark cycle, the day-night cycle is part of what kind of helps our body clock stay in sync. But it's not the only one. There's when you eat, when you're having caffeine and when you're exercising.

Norman Swan: So, a lot of them are common sense. You get up, you have your breakfast, you have exercise before you have your breakfast, so that you're out there in the morning light. That is going to help to train your body and reset your body clocks (there's more than one body clock) and help shift your chronotype to that earlier phase, at least for the period of time that you do that. It may drift back if you stop doing it because of the genetics, but there are ways of changing it. Cooler temperatures can help reset your body clock. And then there's melatonin itself. So melatonin is a hormone that is produced in the evening and helps you go to sleep. 

Tegan Taylor: We did a whole episode of melatonin that we'll put a link in this episode's show notes because it's a deep seam to mine.

Norman Swan: Indeed. And coming back to that paper I mentioned earlier on ADHD and chronotypes, melatonin can help people with ADHD normalise their sleep-wake cycle, and in fact improve their mental health overall.

Tegan Taylor: So coming back to Kerry's question, 'We're hard wired, and can it be changed?' I'm thinking yes and yes.

Norman Swan: Indeed, although for people who are at the extreme end, say, waking up at three in the morning and their day begins at three, that's a much harder task, but still not impossible. 

Tegan Taylor: So what's our bottom line for Kerry and anyone else who's been perhaps frustrated at the way that they feel at certain times of day?

Norman Swan: It's not a problem unless it's a problem for you. This is the way of life, and you shouldn't be anxious that you're going to get dementia if you are an owl or a lark. The reality is that's just the way you are, and it's only a problem (I'm just repeating myself) if it's a problem for you, in other words, you're mismatched with your partner, it doesn't fit your work cycle in terms of when you have to be on for work, in which case you can do something about it.

Tegan Taylor: So a couple of lifestyle changes, like we just mentioned, can help you shift by a couple of hours.

Norman Swan: And we'll have a lot of references on this on our website, so you can really confuse yourself. 

Tegan Taylor: Well, Kerry, thank you so much for the question, and thank you for the opportunity to get back into talking about sleep. If you have a question for us, you can email us, our email address is thatrash@abc.net.au.

Norman Swan: What have we got in our mailbag this week? 

Tegan Taylor: Ah yes. Andrew was listening to our episode about methylene blue that we did last week. We were talking about it as a health supplement with very, very thin evidence, but Andrew wanted to make the point that it's used in lots of applications. Andrew says, 'In 1976 I started work in a dairy testing laboratory in Tasmania. I was testing milk for microbial quality, and basically you put methylene blue into the milk, turning it blue, and then you waited and measured the time it would take to go white. The longer it took to go white, the lower the bacterial counts, as in a better-quality milk, unless there was a preservative or antibiotic in there, which happened occasionally.' He said, 'The stories of people drinking the methylene blue were known and the blue urine was known, but I didn't know anyone that actually did it. Many years later,' Andrew says, 'I've used methylene blue dye to test for the cation exchange capacity of soil. And there's also a test using this for working with concrete. So it can have many uses in our society.'

Norman Swan: Yes, but most of them, as you'll notice, are external to the human body.

Tegan Taylor: Yes, and most of them are used by people called Andrew, because our other email this week is from Andrew, who said, 'I loved your balanced approach to your episode of methylene blue, but I was waiting for you guys to mention in your discussion that methylene blue is also used to treat infections in fish kept in aquaria.' 

Norman Swan: Good old fish. Thank you, Andrew, for letting us know that. It does have a lot of uses. It's just that when you swallow it as a human being, just be careful what you wish for.

Tegan Taylor: Well, you can email your feedback to thatrash@abc.net.au, and we'll be back with you again, rashing it up next week.

Norman Swan: We will.