How do people get up this early?

It's 11am.

I've always been a night owl... so do you prefer to stay-up late and then sleep-in?

Or do you go to bed and get up early?

Or maybe you're somewhere in between.

This is called your "chronotype" and for a long time scientists have wondered why we see such a variation between people, and what sort of effects it has on your health.

Luckily we're waking up to some answers!

For starters, the moment you feel like you should go to bed appears to be influenced by your genetics, and this wasn't discovered by a university or traditional research institute!

It's the work of the personal genetic analysis company Twenty-three and me - quick footnote, you've met 23&me in a previous episode where you discovered that I'm very white.

They sponsored that episode, though they're not sponsoring this one.

They looked at DNA from over 100,000 people who sent in spit samples and answered surveys.

One survey question asks participants if they're naturally a morning or night person.

By comparing the DNA of night owls, to the DNA of morning people, the company found fifteen genetic variants linked to chronotype.

And these differences aren't just hanging out in random places in the genome.

About half of these genetic variants were near genes linked to your body's internal clock, it's circadian rhythm.

Others were near genes involved in sensing light.

This makes sense when you're talking about natural sleep cycles, and it means that whether you prefer to stay up late, or get on early start, you were probably born with that tendency.

It's in your DNA.

But this is a point where I grew skeptical, because both my Mum and Dad get up super early.

I can't blame them... for this.

Beyond your genes, other aspects of your biology and physiology are also related to your chronotype.

For example, people tend to wake-up earlier as they get older and, generally, women are more likely to be morning people than men.

But there's more to it than that.

One study looked at the brains of night owls versus morning people and found that people who prefer to stay up late have lower levels of white matter stability in certain areas of the brain.

White matter is made of the parts of brain cells that are covered in fatty myelin sheaths.

The myelin allows signals to be sent quickly from one brain region to another, and gives white matter its colour.

The study found differences between night owls and early risers that imply a form of chronic social jet lag for people who naturally stay up later.

And if you look at personality and behavioural differences between morning and evening people, this makes sense.

Sometimes I feel like I'm always jet lagged.

Now I can call it, chronic social jet lag.

Morning people tend to be more cooperative, agreeable, conscientious, and proactive.

They're also just happier on average.

Night owls, on the other hand, have a higher risk for depression.

They eat more than morning people, and the type of food they eat is less healthy.

They're more likely to abuse nicotine and alcohol, and they're at higher risk for things like sleep apnea.

Cool.

Luckily, there are also perks.

An average, night owls are smarter, and they have more intercouse.

More interpersonal relations.

Both groups show the highest aptitude for problem solving when they're naturally most awake, and the highest levels of creativity during their less alert hours, whenever that may be.

Here's another footnote, if you would like to watch this video and figure out when that is for you.

Overall, whether you wake up and go to bed early, or late, neither is going to make you healthier, wealthier, or wiser.

Sorry Ben Franklin.

Finally, because evolutionary biology just has it's own way of explaining everything, one theory says variations in sleeping patterns may exist to make it more likely that someone will be awake and "on watch" in case there's a predator or other emergency.

Since my dog and I both sleep until 10am, this is really not that relevant in my home.

We're both just sitting ducks.

So I'm interested to know if you're a night owl or a morning person, and how that's changed over the course of Contact me.