A couple of weeks ago I asked students in one of my classes whether they were early risers or night owls. Almost all identified as one or the other. But is either being up at dawn or burning the midnight oil simply habit, or is something else going on?
Humans are no different to most of the other creatures on earth. We have an internal body clock, which determines a 24-hour rhythm to our activity. This clock can be found in the hypothalamus, at the base of the brain. Across the animal kingdom, the majority of species are either nocturnal (active at night) or diurnal (active during the day).
I’m not nocturnal
I should know: I spent the best part of ten years following around a nocturnal species to better understand its social and mating behaviour.
Possibly not one of my better choices given that I have always functioned best when I go to bed and also get up early. I always liked the Benjamin Franklin quote: “Early to bed and early to rise makes a man healthy, wealthy, and wise.”
It turns out — although fundamentally diurnal — most humans also show distinct preferences for different times of the day and night. Your chronotype is your preferred time of sleeping and activity.
Ten percent of people qualify as true early birds, twenty percent as night owls, and everyone else falls in between. Morning people have brains that are most active at 9 am, whereas night people have brains primed for action at 9 pm. Research tells us that going to bed between 11 pm and midnight and waking between 7 and 8 am is the most common pattern among humans.
If you aren’t sure where you sit on the early—late continuum, you can take this test to find out.
But does it all come down to habit? Or do the brains and genes of early birds and night owls actually differ?
It’s in your genes
The simple answer is yes. A number of studies have identified genes that influence a person’s chronotype. The genes known as PER1, PER3 and ABCC9 all play a role in regulating our body clocks and vary predictably among people of different chronotypes.
And in your brain
Scans have also found true structural differences between the brains of early and late risers. In night owls, the quality of the white matter in the brain is compromised. White matter has the job of ensuring effective communication between the nerve cells and changes here have been linked to depression and other psychological problems.
Whether these structural differences in the brain are the cause — or result — of being a night owl, we don’t yet know.
Does your chronotype matter?
On the one hand, no. If you are able to get enough sleep, feel alert when you need to, and are generally happy with your chronotype, there’s no problem.
But a large body of research highlights problems faced by night owls. The main issue is a potentially large mismatch for night owls between social and biological time. Although night owls may not feel tired until 2 am, they probably still need to be up at 7 am in order to get to work on time. This mismatch has been called social jetlag. Our lives are generally structured to suit morning, but not nighttime people.
Studies have found that night owls who experience this conflict between internal and external time suffer more from mental distress and are more likely to smoke cigarettes and drink alcohol than early birds. Night owls also experience worse sleep and tend to score highly on personality tests looking at psychopathy and narcissism.
Can you change?
If you’re a night owl who wants to be an early bird, what are your chances of switching?
Probably very good, if you are willing to embrace some new habits, says sleep researcher Dr Simon Archer.
It is not all to do with your genetics. You can choose to follow a particular life pattern. You can override your genes. Dr Simon Archer
Camping might be the answer
Researchers took eight people camping in the wilderness of Colorado. Some were night owls, some early birds. No torches or electronic devices were allowed and within one week the circadian rhythms of all of the campers were synchronised and timed with sunrise and sunset. At the end of the week, all were happily rising at dawn. The key: taking away access to artificial light (think lights, mobile phones, tablets, TVs and computers) after the sun has set.
Regardless of your genetic predisposition, making changes to your habits could make all the difference.
But if you’re a night person and avoiding artificial light after sunset doesn’t appeal, another option is to change your schedule to better match your chronotype. There have been many calls for the work or school day to run from 11 am to 7 pm for the night owls among us.
Sound appealing? Now you know the science to convince your boss.
Links and stuff
- Want to take a more detailed chronotype questionnaire and compare your profile to 50,00 other people?
- A short video explaining social jet lag
- Read more about the benefits of camping and getting away from artificial light
This post was referenced on iflscience.com