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Think about how you feel when your alarm goes off in the morning. Do you hit snooze as many times as you can get away with or do you jump out of bed before the buzzer goes off? It will probably only take a second of thought for you to determine if you’re more alert in the mornings or the evenings.
It’s a fun piece of personal trivia, but what you may not realize is that being an early bird or a night owl (or somewhere in between) also has a scientific name — chronotype — and it influences your life in some surprising ways.
What Is Chronotype?
Your chronotype is your body's natural sleeping rhythm, or as Dr. Carleara Weiss, Ph.DMS, RN, and Aeroflow Sleep’s Sleep Science Advisor, puts it, “a natural preference of our internal ‘biological clock’ towards sleeping at a specific time.”
Your chronotype determines whether you’re a morning person or a night owl, but it has implications far beyond when you naturally feel like falling asleep. Dr. Weiss says that chronotype is also associated with personality traits, mood, attention, concentration, and performance. While staying up late or waking up early may seem like a choice, there’s more to it than personal preference — in a way it is who you are.
“Understanding your chronotype leads to honoring your body’s natural sleep-wake cycle and ensuring optimal health,” says Loren Bullock, editor and Certified Sleep Science Coach at Mattress Nerd. “While light plays an important role in each person’s circadian rhythm, so does genetics. In fact, research shows that at least 15 genes contribute to our circadian rhythm.”
Other factors that can influence chronotype include age, whether you live on the east or west coast, and season, though for the most part after childhood your chronotype stays relatively stable.
The Menagerie of Sleep Types
While chronotype is often divided into two categories – night owls and morning larks with everyone else falling somewhere on the spectrum between the two – Bullock says researchers have found there are actually four chronotypes.
The four types as defined by a 2019 study are:
Morning larks tend to wake up feeling alert. They’re the people who are up first on vacation, the ones you hear in the kitchen making coffee at what feels like an absurdly early hour if you aren’t one of them. Children also tend to fall into the lark category (as all parents of toddlers can attest). They get sleepier as the day goes on and are typically ready for bed early. Some research suggests that these early birds may be less prone to mental health conditions like schizophrenia and depression.
Night owls feel groggy in the morning. They’re the ones making a second batch of coffee because there’s none left by the time they get up. They tend to feel alert around 10 a.m. and after that their energy stays high throughout the day. These evening fliers will be awake and alert long after their morning lark friends have conked out. One study found that night owls tend to be creative and score higher than others on inductive reasoning tests.
Afternoon people tend to wake up the sleepiest (even more so than night owls). They start to feel alert around 11 a.m, which lasts until about 5 p.m. after which they may begin to feel sleepy, a feeling that will intensify until they go to bed in the later evening.
Nappers were the only group of surveyed individuals who showed a double-peaked sleep curve throughout the day, according to Psychology Today. What this means is that nappers start out wide-eyed (like their morning lark friends) but by the time 11 a.m. rolls around, their energy is waning and will continue to do so, until about 3 p.m. This group often naps at some point, hence the name. After grabbing a midday rest, they’ll get a second burst of energy that will carry them through to about 10 p.m. Their superpower is that, even without a nap, they generally still gets a second burst of energy in the late afternoon.
Quiz: What Chronotype Are You?
You probably have at least a general idea of your chronotype after reading the descriptions, and it’s worth noting that chronotype research is always shifting, so it’s possible that you’ve heard chronotypes described differently (maybe using animals like lion, bear, and dolphin) before.
“There are several quizzes and sources to identify your chronotype; however, the Morningness-Eveningness Questionnaire is one of the best scientific-proven assessments,” Dr. Weiss says.
In addition to questions about your sleep preferences, the quiz asks sleep-adjacent questions like how hungry you feel in the morning or when you’d prefer to do a hard workout.
Because I’ll take any excuse to do an online quiz, especially if it’s doctor recommended, I took the quick questionnaire and found out I was firmly in the intermediate category (my results were dead center), though the scoring of this quiz does not specifically account for the additional two newer categories (afternoon and napper). Pairing what I learned from the quiz with the information about the four types, I believe I am a napper. (This scientific conclusion was also informed by the fact that I would nap every afternoon if I could).
How to Harness Your Chronotype for Good
First things first, you can’t really change your chronotype, though it may change gradually on its own (which is why kids sometimes need special lights to tell them to stay in bed, and adults need the reverse).
Once you know what type of sleeper you are, you can harness the information for good in your life. “Don’t fight your chronotype,” Bullock says. “You’d be trying to fight against the natural rhythm of your body. Instead, embrace it. If you’re a ‘night owl,’ align your sleep schedule to it. If you’re a ‘morning lark,’ perhaps schedule your highest priority tasks for the am.
Nappers may not be able to sleep every day, for example, but they can try to set aside 20 minutes in the afternoon to relax or step away from work. Afternoon people may schedule exercise in the later afternoon when they’re alert but not yet too tired.
How Hormones Fit the Chronotype Picture
Sleep and hormone health are closely related, so it makes sense that your chronotype would influence your hormones. Weiss says cortisol, leptin (which regulates satiety by telling the brain when you are full), and ghrelin (a hunger hormone that tells the brain it’s time to eat) are all influenced by chronotype. “Chronotypes can also regulate progesterone levels during the luteal phase of the menstrual cycle.”
A 2020 study found that women described as morning larks show earlier increases in estradiol levels during their menstrual cycles than women in the intermediate category. The same study found higher testosterone was observed in adolescents with “higher eveningness” (aka night owls).
You may think that something you find out in an online questionnaire can’t have too much meaning in your life (looking directly at quizzes like “Which Piece of Ikea Furniture Are You?”), but that’s not the case with your chronotype. Knowing which category you fall into will help you set a healthy sleep schedule and it may also shed light on how to structure your day to play to your strengths.