Whether you’re listening to a news podcast debating the merits of changing school start times or consuming IG content from an expert urging the government to end daylight savings time, you’re likely to hear the term circadian rhythm referenced often. Those are two real-life topics of debate that show how many sleep doctors are united in legislating for change that allows people to live in harmony with their natural sleep predispositions, or “sleep chronotype.”
The concept centers on how your body, influenced by your internal clock, has an innate preference for mornings or evenings. You’re probably familiar! Now, research is revealing just how much honoring your natural rhythm matters for your overall well-being. It’s finally time to quit fighting your sleep tendencies and instead lean all the way in to maximize life around yours.
Understanding Chronotypes
Think of it like your height: genetically determined and somewhat unchangeable.
“People are beginning to understand that their chronotype is biological, and it’s not something to do with attitude or willpower or whether you’re a productive per- son,”
says Jennifer Martin, PhD, president of the American Academy of Sleep Medicine and a professor of medicine at UCLA.
While genetics plays a major role here, environmental factors matter too. “Sleeping environments or poor sleep hygiene—like using your phone late at night can also influence patterns and impact chrono- types,” says Shelby Harris, PsyD, a clinical psychologist in New York who specializes in behavioral sleep medicine. Inconsistent eating patterns and the fact that many people don’t get substantial natural light during the day are also part of why there’s a broad variance in chronotypes today.
You may not be able to totally fight your hardwiring, but you can control some of the lifestyle issues around you, and they’re a bigger piece of the puzzle than you might think. For instance, if you’re already an evening type but get caught up in “revenge bedtime procrastination” and don’t fall asleep until 1 a.m. and then can’t get out of bed in the morning. you may go from a natural night owl to a troubled sleeper chronotype.
Age and gender also factor in, says Wendy Troxel, PhD, author of Sharing the Covers: Every Couple’s Guide to Better Sleep and a sleep scientist at the RAND Corporation.
“Teenagers naturally stay awake and sleep in later,” she says. “And it’s not just a preference; their biology shows it as well.”
For example, teens release melatonin the hormone that signals sleepiness later in the day than adults or younger children. And as people age, they tend to shift in the other direction, with older people becoming more likely to be early risers. Women in general are also likelier to be morning types, whereas men lean toward evening tendencies, says Troxel.
The Reality of Going Off Schedule
Circadian misalignment (i.e., when your lifestyle isn’t in sync with your internal clock) can increase the risk for various health conditions, including obesity, type 2 diabetes, cardiovascular disease, infertility, mood disorders, and impaired cognitive function, research has shown (ugh).
In fact, the circadian system modulates practically all aspects of your physiology, a recent review in the Journal of Sleep Research found, with the authors going so far as to assert that “one could argue that circadian health is equal to general health.”
In addition to protecting you from disease, understanding your chronotype allows you to align your daily schedule with your natural sleep-wake patterns, which can help increase productivity and well-being, says Harris.
This helps you feel more energized and perform better mentally and physically. For example, while morning work- outs are great for those of us who are early birds, “if you’re an evening type, you’d be wise to work out in the afternoon or early evening hours when you’re just naturally more alert and motivated,” says Troxel.
Being aware of when you’re biologically more primed for a task can help you plan and crush it.
Keeping all of this in mind when you’re scheduling important meetings or an interview, for example, can mean you show up feeling your best. And if your work schedule is flexible, you can even set up your day based on your patterns. For instance, maybe a 7 a.m. to 3 p.m. work schedule better suits you, or a noon to 8 p.m. operation is more your jam.
This could also be helpful on a more global scale: “We might actually maximize productivity in the workforce by identifying employees’ circadian preferences and allowing more flexible work schedules,” Troxel says.
Discovering Your Type
Now, let’s bring it back to you. Exactly how many chronotypes exist and what de fines each of them is a somewhat nebulous space that depends on who you ask. You may have heard the terms wolf, dolphin, lion, and bear (as well as a slew of other seemingly random animals) thrown around over the years; these are , obviously, not based on any animal- persona science. (Just “pop culture terms,” Harris notes.)
Forget all that and begin by simply identifying as having either “ morningness” or “eveningness” tendencies, Martin says. Go with your gut: “Thinking about what time of day you function and feel your best can give you a good sense,” says Troxel.
If you relish being up at 5 a.m., then you’re probably a morning type, whereas if you reach your peak at 11 p.m., you’re probably a strong evening person. It can be helpful to think about Vacation You, says Martin. “If you’re the kind of person who can’t wait to get up at 6 a.m. and get out on the golf course, you’re probably a morning person.
If you like to stay up late and go out and sleep in, you’re probably more of an evening type.” Harris then segments morningness and eveningness each into two distinct chronotypes for even more personalization: early riser, moderate morning, night owl, and trou- bled sleeper.
Two more tech-driven routes for discovery: Take an online quiz (Harris suggests chronotype self test) or invest in a sleep track- er that provides detailed insight into your sleep-wake patterns, like an Apple Watch or Oura Ring, the latter of which recently launched a chronotype feature.
“Over 90 days, Oura Ring app analyzes how different physiological signals, like your heart rate, respiratory system, and temperature tend to behave,” says Caroline Kryder, Oura’s science communications lead.
It then leverages that information to determine your natural circadian rhythm when your body naturally winds down and wakes and assigns you to one of six chronotypes. (You’ll also get advice on how to adjust your sleep to align with your clock.)
The Science of Sleep Shifting
Okay, let’s say you don’t want to go to 7:15 a.m. yoga—but it’s the only chance you have to exercise, due to work and family commitments.
Hear this: “It’s possible to adjust sleep-wake patterns to some extent and shift toward becoming more of a morning person, even if you’re naturally a night person,” says Harris.
The idea is to do it steadily and gradually so as not to suddenly derail your body. Adjusting to a new or slightly different chronotype should be a two-step process, Martin says. First, get on a regular sleep-wake schedule in general, which could mean you’re not making it to your workout class yet but consistently hitting the sack at midnight and waking up at 8 a.m.
Then start to make little adjustments to get your bum out of bed by 6 a.m., like going to bed and waking up 30 minutes earlier every few days. You’ll also want to get outside to expose yourself to sunlight first thing (maybe that’s a walk around the block at 6:15 a.m. and an energizing protein smoothie at 6:30).
And since our clocks adore consistency, that means waking up within an hour or so of your ideal alarm time every day, even when you don’t plan to work out. Another key takeaway on this subject is that consistently eating and exercising at the ideal times (notice that consistent is a theme here?) for your chronotype is arguably as important as maintaining a rock-solid sleep schedule.
“It’s the behavioral anchors of exercise and diet that can help you capitalize on having a really strong circadian rhythm,” says Martin.
Plus, regularity benefits everyone. “Whether you’re a morning type or an evening type, we all do better as human beings following relatively predictable routines,” Troxel says. “The im- portance of routine is true across morning types, evening types, and those who fall in between.”
