Why Your Chronotype Matters More Than You Think

Have you ever wondered why you feel sharp and focused at dawn while your partner hits their stride after sunset? Or why your teenager seems to come alive just as you're winding down? These patterns aren’t just quirks—they’re rooted in biology. In this episode of Speaking of … College of Charleston, Psychology professor Cindi May unpacks the science of chronotypes and circadian rhythms, revealing how our internal clocks influence everything from academic performance and medical diagnoses to relationships and daily decision-making. Whether you're a morning lark, a night owl, or somewhere in between, understanding your chronotype could be the key to unlocking your best self.

“Your chronotype is your natural preference for sleep and wake times, and it’s driven by your circadian rhythm,” says May. “These rhythms are powerful internal timekeepers that affect your body temperature, hormone levels and cognitive functioning throughout the day.”

While society isn’t always structured to accommodate individual chronotypes, May believes awareness is key. “Understanding your chronotype isn’t just interesting, it’s empowering. It helps you advocate for yourself, whether you’re scheduling a test, a meeting, or a medical appointment.”

Tune in to learn how understanding your natural rhythm can help you optimize your outcomes and navigate a world often out of sync with your internal clock.

Resources from this episode:

·      Take the Morningness-Eveningness Questionnaire to determine whether you are a morning type (lark), evening type (owl) or neutral. 

·      Cindi May: https://charleston.edu/psychology/faculty/may-cindi.php

Transcript

Welcome back to another episode of Speaking of College of Charleston. Today we're talking to psychology professor Cindy May. May's expertise is in human cognition, aging, and intellectual disability, and she teaches courses on memory, cognition, and aging. Her research is aimed at developing strategies and interventions that optimize cognitive performance and outcomes.

Especially for populations who experience cognitive challenges, she has examined an array of factors that affect cognition, including circadian rhythms, emotion, curiosity, and educational settings. Cindy, thanks for joining us in the studio. We invited you here to talk about your research on early birds and night owls, or more accurately circadian rhythms and chronotypes.

for our listeners, can you explain what are chronotypes and circadian rhythms? Sure. First, let me say thank you for having me. It's always fun to talk about this research, and I think it's something that we all can connect with because we experience the influence of our chronotype and circadian rhythms every day.

So your chronotype is your natural preference for sleep time, wake time, and feelings of alertness during the day, and it's determined by your circadian rhythm. And circadian means. Circa dm right about a day. So these are natural rhythms. You can consider them to be powerful internal timekeepers, and they influence different physiological processes like your body temperature, your blood pressure, your hormone secretion.

They also influence your cognitive functioning over the day and all species. Experience these circadian rhythms. Um, and the interesting thing is that although for humans, we all have these rhythms, the exact timing of them varies across individuals. So some people wake up feeling bright-eyed, bushy tail ready to seize the day.

They don't need their coffee. They wake up at the same time without an alarm. Over the day, their energy wanes and maybe by nine or so at night, they're ready for pajamas. These would be considered morning type people, or some people call them larks. Other people are just the opposite, so they hit the snooze button a few times.

They're fuzzy and foggy in the morning. They are reluctant to get up, but their energy increases over the day and they have no problem burning the midnight oil. These would be considered evening types. Some people call them owls. And then there are lots of folks who fall in between who are neutral types.

They're not necessarily raring to go in the morning, but they're also not eager to burn the midnight oil. That's fascinating. and I have always known,just by instinct what type I am. How can people, if they're curious, how can they find out what type they are?

Yeah, it's actually quite easy and a little bit fun to determine your chronotype. So if you want a precise score, you can get one. You can simply search for the morning ness, eveningness questionnaire online. It's a simple questionnaire of about 19 questions, and these questions will ask you about your sleep wake preferences, how you feel intellectually and physically early in the morning, how you feel intellectually and physically later in the day.

And so if you take the really quick questionnaire, you can figure out whether you're a strong or a mild morning type, a strong or a mild evening type, or if you fall in that neutral category. Honestly, you really don't need to take the questionnaire because most of us have a pretty good sense. Mm-hmm. In fact, the last question of the questionnaire is, do you consider yourself a morning type, neutral type, or evening type?

We know what we are naturally, and so most of us have that, um, instinct or sense of what we are. And it, it changes over time too, right? Likewhen you're younger, you could be an early bird and then when you are in high school, most kids end up being night owls ab and then it changes again right?

Throughout your life. Absolutely. So the, these chronotypes and these preferences are determined by a lot of different factors. So there's biology that plays a role. Your genes play a factor. The environment plays a role. For example, getting exposure to bright light early in the morning can really wake you up.

There are social factors like the demands of your job or your family, and then there's a very, very powerful individual difference factor, and that is age. And so what's interesting about this is that across cultures and continents, we see the same developmental path. Little children, toddlers, little kids tend to be strong morning type people.

Ask any mom of a toddler or dad of a toddler, they will tell you they are up with the sun. They are ready to go. But as we go through puberty, as we hit adolescence, there is a strong shift. And that is a time where we see a shift away from morning this and towards Eveningness. And by the time you're in your late teens and early twenties, that's a really strong pattern.

So, as one example, there was a recent study done up in Michigan with college students. 20,000 college students, a large number of them, 30% showed eveningness tendencies. The majority were neutral types, but even those neutral types were towards the eveningness end of the spectrum. And very few, less than 10% were morning types.

Huh. And so this is a very big shift. And then what we see is that gradually over time we shift back. So throughout adulthood, from our twenties to our sixties, we experience another shift. And by the time you reach age 60, the numbers have flipped. So the vast majority, about 70% of older adults, and this, again, this is Europe, Asia, north and South America, we see about 70% of older adults are morning types.

The majority. The rest of the folks, 25% or so, are neutral types. And those neutral types tend to be leaning towards the morning type end of the spectrum, and very few older adults, less than 5% are really strong evening types, and there are individual differences in there. I'll give one example. My mother-in-law who's 87, considers herself an evening type.

She does sleep in till about nine in the morning, and she is up till about 11 at night. So compared to her peers, right, she's more evening, but compared to a teenager, right. Who's sleeping in, they're just getting going at 11, right? They're going out at 11 at night. Yeah. She's not a true evening type. And so this is a pretty powerful, um, developmental trend that we see cross-culturally.

And why, like developmental trend? is therea purpose of evolution, a reason that. Throughout life, we, you know, does it have to do with like survival of the fittest or, well, let me be clear. My answer here is speculative. Right? Right. But you could speculate that as we come into our prime physically reproductively, cognitively we are in our prime, in our late teens and our twenties, that would be the time that you would want to be there to protect your tribe, so to speak.

From predators at night. And so it would be good to have. Your strongest people there, um, at times when you would be vulnerable. Right? And so that's speculation, but it would fit with an evolutionary explanation. That makes sense. Yeah. Um, and it's also the case that it, if you think developmentally, I.

Grandparents, I think historically played a big role in helping raise kids. Right. It helps that they're on the same circadian path as the little ones. Yeah. Right. Um, so that parents who may be at one time were hunter gatherers and busy, otherwise, the grandparents could have played a role in raising kids.

That's fascinating. And so what it makes me think about is how many of us are going against type, you know, like, I mean, the clearest example is high schoolers who have to be shockingly in class by 7 30, 8 o'clock in the morning when their body wants to still be sleeping. You know, or people, other examples of somebody who has to work the night shift, but they'rean early person.

And so, we're going against our nature because we're forced to by society rules and regulations. what about those people, how, what happens to their mental wellbeing or physical too? It's a great question and I think a first question might be.

Does it matter? Right? So we have these natural preferences. Some of us are eager to get up in the morning, others are not. Does it really matter? And that is something that we and other researchers have looked at in our labs. The question, do these chronotypes matter? And the answer is yes and no. And let me clarify that.

So if you have a strong chronotype, if you're a strong morning type person or a strong evening type person. And the task requires careful analysis. Attention to detail, thinking really carefully about information difficult retrieval, skepticism. I. The answer is yes, it does matter.

And so I can give you a couple of examples. We've looked at vigilance tasks and attention, and so one task that people are given, uh, is one that looks at their ability to really pay attention and make an appropriate quick response. But when necessary to withhold that response. And you can think about this like driving, right?

If you're driving along, you need to make quick decisions, and if something runs in front of your car, you need to be able to step on the brake. So this is a simple task. People see numbers on a computer screen the numbers one through nine, and their job is simply to press the space bar as fast as they can when they see a number, unless it's the number three.

When it's the number three, you have to withhold your response. And what we see is what we call a synchrony effect. And the synchrony effect is the finding that people perform best when they are tested at a time that aligns with their chronotype. So morning type people do better in the morning and evening type people do better.

In the evening, and we see this across task of attention, language, memory, decision making, persuasion. Um, as another example, people are willing to invest more time. They're more skeptical. They do careful analysis when they're making a complex decision. If they're doing it at their peak time of day, at their off peak time of day, you're far more susceptible to celebrity endorsements, to flashy pictures, to images.

You go with your gut. Sometimes that works, and when it works, you're gonna be fine At your off peak time of day, there are lots of tasks that you might do, including. Mundane shopping, filling out paperwork, checking routine emails. Those kinds of tasks are gonna work well at your off peak time of day, whether you are a strong chronotype or not.

But when you're really having to pay careful attention to resist distraction, uh, to think in a detailed analytical way, then you're going to be impacted. And so what happens? When we take someone whose chronotype is an evening type, for example, and we have them try to perform in the morning. And this does happen all the time.

So as you mentioned, high school students have to be in school early. Mm-hmm. What's interesting is that they also take the SAT at 8:00 AM right? Yeah. At 8:00 AM And so naturalistic studies show that there is a price to pay. Some of the best studies are ones that have looked at hundreds or even thousands of high school students.

And I'll talk about just one study. They took 700 high schoolers and they randomly assigned them to take tests either in the early morning, the late morning or the late afternoon. And with that large of a sample, you'll have some who are morning types and a large number who are evening types. And what they found, um, the pattern of findings aligned with synchrony effects.

So at both morning. Testing times, either early morning or late morning. The morning types outperformed their evening type peers. The evening type students came on, right? Their performance improved over the day, and by the afternoon, any of that advantage that the morning types had shown disappeared because the evening type students did well.

So there are consequences, and these consequences in the lab are moderate but meaningful. So it's about a 10% difference in performance. For a student that could be a difference between an A and a B, That's a big difference. Yeah. Where I think we really need to think about these consequences are in more applied settings.

So for example, with neuropsych testing. So neuropsych testing is used to assess for things like autism or attention deficit disorder, Parkinson's disease and Alzheimer's disease. And let me give two examples here. So for attention deficit disorder. You are looking at a person's ability to resist distraction, to stay focused.

These are precisely the abilities that are impacted by that synchrony between your chronotype and the time of testing. And so your score could vary depending upon when you have your evaluation for something like Alzheimer's. Alzheimer's is not a simple diagnosis. You don't go in once. And get that diagnosis.

Oftentimes, neurologists are looking for change over time, so they'll test you at one time and maybe six months later they'll test you again. Imagine that you go in initially and you're tested at your off peak time of day, and then the next assessment occurs at your peak time. So you're receiving a bump in performance, right?

Just because you're tested at a better time. And that could mask some of the cognitive deficits, right, that you are experiencing. Um. Alternatively, if you're tested at your good time of day first and then your bad time, the decline might be that's not necessarily right and accurate. Artificially exaggerate.

and so to get accurate assessments, particularly for older adults. Older adults show pretty strong. As I said, 70% are morning types and they tend to show bigger synchrony effects. So it's really important. You may have heard the expression sundowning that some patients with Alzheimer's experience 

So they may be pretty good in the morning and then in the evening there are behavior in their cognition really can deteriorate. So the differences can be pretty, um, strong, particularly for older adults. And this is something that we need to keep in mind when testing. That's really interesting. And then whose responsibility is it?

I mean, I, I guess you have to be your own advocate. You have to be aware of what chronotype you are and then if you have the ability to schedule appointments at a certain time of day, because I just feel like there are so many things that,that shape who we are. 

We're constantly learning about ourselves and it's whether it's your chronotype or whether it's your. Myers-Briggs type, or whether it's your working genius style or, you know, there's so many things to know about yourself that, you really have to be educatedand an advocate for those types of things.

'cause nobody else is gonna tell you it's true. And I will say, so sometimes when you list all of those things, people just throw this in as another nuisance factor. Something else we have to work around. But if you're looking for an accurate diagnosis, And folks in the medical field are aware of circadian rhythms, so you may not know this, but more heart attacks occur in the morning, for example, 'cause of the way, because of changes in blood pressure, et cetera.

There are certain medications that are more effective at certain times of day than in others. So the medical field is aware of this. We are not always structured in our society. To take advantage of this and to be cognizant of it. But I do think it's something that both patients and the medical field could work towards.

So some, you know, if you are having pain in your foot, that's probably not gonna matter when that appointment is scheduled. some clinics, particularly dealing with older adults need to be cognizant of that. And then I think about all the things, the pharmaceuticals that people use to help them manage throughout the day.

You know, if, if they are, having to work late or, drinking a red Bull or something to stay awake in their off peak hours. Right? And, and the different things that we, ourselves and, and exercise too, I would think when you exercise probably matters per chronotype. Well, there are ways. So there are sort of two interesting points to make here.

There are ways to combat that dip that you experienced at your off peak time, and some studies have shown that having a caffeinated beverage. I'm not necessarily advocating for Red Bull, but Right, right, right. Maybe a cup of coffee can help offset some of those disadvantages. Um, it is true that exercise has an impact.

Exercise and light are two environmental factors that really affect your circadian rhythm. And so if you're a person who has to operate early in the morning and that's not your chronotype exposure to bright light And exercising the morning can really benefit you. If you're a morning type person who likes to be able to go to bed at nine at night waiting until 8:00 PM to do your exercise, 

It's not gonna serve you well. Yeah. You need to be cognizant of that so you can use exercise and light. I. It's a monkey around. Mm-hmm. With your circadian rhythm, it is a great way to help reset. If you're traveling internationally and you need to reset your clock, using light and exercise to reset your clock can be very effective.

But because they can be effective, they can also impact if you're a person and you think I'm going to do all of my work and then I'll save, you know, my evening when I'm at my off time for exercise that can wake you up mm-hmm. And make it more difficult to get to sleep. And nutrition too, I'm sure has a factor with, if you're a night person, but kind of not forcing yourself, but, but making an effort to have a healthy breakfast to kind of get your day going.

Right. Well, all of the advice that I have read suggests eating heavy meals late is not good. Yeah. For anybody. Yeah. But especially if you're a morning type and you are planning to go to bed around nine, you don't wanna be eating right. Really late. Okay. Um, and so we've been talking about this a little bit, but just aligning your schedule with your chronotype 

So, um, can you talk a little bit about strategies for. Optimizing outcomes for chronotypes. Sure. Given that most people have a pretty good sense, um, you need to think carefully about how you schedule your day. Mm-hmm. So it used to be the case that I would come in and the first thing I would do is check email.

I. That's pretty easy, right? That's a task that I should probably save for my non-optimal time of day. Um, you wanna save the tasks that require that detailed thinking, the careful analysis. For example, balancing spreadsheets. The other night I was trying to balance my checkbook and I just missed. One big check.

Mm. I spent an extra half an hour trying to figure out what I had missed. Yeah, so that's a task I should have saved for early in the day. Um, you have to figure out when should you tackle your chemistry textbook, um, making medical decisions. So medical decisions are complex if you have cancer, for example.

You may be considering a combination of chemotherapy, radiation, surgery, et cetera, um, even medication decisions, because medications all come with side effects. Making those decisions about what is right for you. When you have to compare competing factors and do a more detailed analysis, save that for your peak time of day.

Mm-hmm. There are lots of things though that we can do. The routine emails that are off time of day, making your favorite recipe, um, inputting grades. If you're a teacher, that's one of the things that I save to do. Um, if you're shopping and you're not making tough decisions, do your routine grocery shopping where you're buying the same things every week at your non-optimal time of day, right?

So many tasks, particularly tasks that are highly practiced, that require rote responses or a gut response. All of those are gonna be fine at your non-optimal time of day. We're not complete blathering idiots, right. At our non-optimal time of day. We just are not capable of the same level of analytical thoughts mm-hmm.

That we are at our peak time 

Um, so lastly, what about chronotypes and relationships? As we're talking, I'm just thinking about, you know, what happens if you are an early person and your husband's or your partner is a night owl, or, or you're both. Early people and you have teenagers, you know, right. Who's gonna stay awake right.

Until they get home? It's a good question, and it's one that I have struggled with personally because I am and have always been a really morning type person. My husband who does shift work is an evening type person, and that's an advantage for him because morning type people have some advantages. We tend to be more conscientious and agreeable, less prone to neuroticism.

Evening type people have greater flexibility often with their circadian rhythm, and that has benefited my husband, but I am up and ready to go to tackle the day in the morning, and he's not. We had to establish a rule of no work, no business after 9:00 PM for me because I don't make good decisions at night.

And so if you have a relationship like we do, you have to learn how to navigate that. And we have come to recognize that we need to schedule a time for more difficult decisions. We need to respect each other. When we say, I really can't think about that right now. Mm-hmm. We, I am genuinely not good at thinking about complex things.

Late at night, I will go with my gut. Mm-hmm. Sometimes that works and sometimes it doesn't. So respecting people's chronotype, I think is a really important thing. And for parents of teenagers, I grew up with a father who was a marine. And. There was very little understanding or respect of why we were sleeping in.

And so I think it's important for parents to understand that this is a biologically driven force. That it is not a sign of laziness or disrespect if teens are sleeping in. It is a sign of something that is. Naturally drawn and like most of the things that come with the teenage years, acne hormones, this two will pass, right?

And so you have to remember that. Uh, try to be respectful, I think of people's natural tendencies because expecting the best out of people at their worst time of day. Is not gonna lead to the best outcomes. Right. It's a lose lose. 

and everybody should remember anyway, we all were teenagers once we all can remember that we were the same way. Maybe your dad has blocked that out from his military. Well, I think the military are a slightly different breed. I, um, did a fun study at the Citadel. Because I've done lots of work with college students across the country looking at circadian rhythms.

My own work has shown the same pattern that was found up in Michigan with those 20,000 undergraduates. I have found that most undergraduates tend to be evening types or neutral types who kind of lean towards Eveningness. So I was curious what would happen that it's the citadel. You know, the, um, Army's motto is we do more before 9:00 AM every day than the most people do all day.

Right? At the Citadel, the cadets are expected to get up and perform, and I wondered to what extent this would impact their chronotype. So we gave the MEQ to the Citadel Cadets, and what was interesting is that their scores were less evening than those that we saw at the College of Charleston. But if you dissect the questions.

The reason for that difference is interesting. If you look at when they prefer to rise and retire, their times were very similar to the students at the College of Charleston, right? They had evening preferences there. And they reported that they would do really well if they were challenged at night, just like the students at the College of Charleston.

The difference was if you asked the students at the College of Charleston, how would you do if you had to perform early in the morning, physically, intellectually. Students at the College of Charleston said, uh, Not very well, but the students at the Citadel. Not only would they be great in the evening, by golly they'd be great in the morning.

Right, right. And so some of that is that military mentality of if we have to show no weakness Right, we can do it. Right. We will do it. Yeah. And so, um, the interesting question there for me was to what extent does the environment and this social demands impact your chronotype? I'm not sure we clearly answered that in the sense that the Citadel students still showed a lot of those evening preferences, but.

Those social factors influenced their thoughts about how they would do in the morning at least. Oh, it's fascinating. I could keep talking about this forever. I think it's all really fascinating. Oh, thank you for coming into the studio. My pleasure. I really appreciate you taking the time During the summer I.

To come in and talk to us and share all of this information with our listeners. Well, thank you. It's been fun.

Thank you for listening to this episode of Speaking of College of Charleston, with today's guest, Cindy May. If you wanna learn more about May's research, go to the psychology page on the college's website. If you liked this episode, please help us reach more listeners by sharing it with a friend or leaving a review.

For show notes at more episodes, visit the College of Charleston's official news site, the college today. At today, dot charleston.edu. You can find episodes on all major podcast platforms. This episode was produced by Amy Stockwell with recording and sound engineering by Jesse Kunze from the Division of Information Technology.