NuroseneOct 22

Sleep Chronotypes

A bird stands on a cliff with the sunset in the background
“She’s been up since 5am. She’s an early bird.”

“I’ve never met such a night owl. He gets his best work done after midnight.”

You’ve no doubt heard something like that about others. You probably know — or think you know — which one you are, too.

We’ve traditionally grouped people as either early birds (aka larks) or night owls. But research is showing us that not only is there much more nuance to it than that, but that your ‘type’ may actually change over time.

What Does Sleep Chronotype Mean?

A chronotype is simply a classification based on your specific natural activity and rest rhythms. And while the jury is still out on just how many exist, we can typically look at 3: morning, evening, and somewhere in between.

Knowing your chronotype — ‘chrono’ means ‘relating to time’ — can help you better plan your day in alignment with your peak periods of productivity. You work with your natural inclinations and sleep patterns rather than against them.

But where do they come from?

Again, the science is only starting to catch up, but they are discovering some factors that might influence it, such as:

  • Genetic variation
  • Age & Gender
  • Environmental Factors

Genetics and Sleep

Research has shown that being a morning person is a behavioral indicator of a person’s underlying circadian rhythm.

Circadian rhythms are fundamental cyclical processes that occur in most living organisms, including humans. These daily cycles affect a wide range of molecular and behavioural processes, such as hormone levels, core body temperature, and sleep–wake patterns. It typically responds to the periods of light and dark that come with the rising and the setting of the sun.

The name derives from the Latin phrase ‘circa diem’, which means ‘around a day’ (there will be no test on this later, we promise!).

Identifying genetic variants associated with chronotype and sleep timing will also provide insights into the biological processes underlying circadian rhythms and sleep homoeostasis.

Further evidence shows that alterations to circadian timing are linked to disease development, particularly metabolic and psychiatric disorders. There are many reported associations between disrupted circadian rhythms and disease.

Genome-wide association studies (GWAS) are being widely conducted to understand this further. GWAS are studies designed to detect associations between genetic variants and common diseases or traits in a population. Click here to learn more about GWAS.

Your chronotype is the interplay of everything to create your peak periods of activity, rest, and productivity.

Still with us? Good.

The Different Types of Chronotypes

So, let’s break down the different types:

Morning people or “Larks” are the embodiment of the phrase “early to bed and early to rise”. Actual larks start their days very early, which explains the word choice for people who may sleep from around 10 p.m. to 6 a.m. (or earlier). Human “larks” tend to feel most energetic just after they get up in the morning. They are thus well-suited for working the day shift.

Line art drawing of a lark

Evening people or “Owls” prefer a later bedtime and later rising time. Night owls tend to feel most energetic just before they go to sleep at night. Some night owls have a preference or habit for staying up late, or staying up to work the night shift.

Line art drawing of an owl

If you don’t feel you identify with either, that’s okay too! People landing somewhere in the middle have been identified as “Intermediates”.

Researchers have traditionally used the terms morningness and eveningness to describe these two phenotypes.

The Benefits of Knowing

Once you’ve identified your chronotype, you can start to apply those insights to your day.

If you’re an owl, for example, don’t schedule anything too demanding until the afternoon when you’re at your best. But if you’re a lark, it’s better to get important meetings and tasks in before lunch.

You should definitely go to bed according to your chronotype. Resisting it is generally a losing battle. Whatever your natural tendencies, make sure you’re getting the recommended 7–8 hours whenever possible.

Other Factors

As we mentioned earlier, other factors including age, gender, and your environment can cause chronotypes to shift over time. Factors include season, latitude, and even whether we live in an urban area. Research has also shown that men are more likely than women to be owls and we become more lark-like as we age.

A great example is the transition from not being a parent, to being a parent. Children tend to be early risers, which can impact their parents for obvious reasons (ever try to sleep in with a toddler?). That morningness is generally pushed back during the teenage years and they become more owl-like, as anyone with a 16-year old can attest. It then starts sliding the other way in our 20s and as we get older.

Lifestyle, genetics, societal norms, and more can all influence our chronotype. The trick is to be open to what your body is telling you, and adjust as necessary.

When you’re aligned with what your body, mind, and brain needs, you’re already ahead of the curve.