The Science Behind Morning And Evening People
Grow Talk by Sofy Robertson
You may count yourself as a ‘morning person’; someone who achieves their best in the early hours and can get up at the crack of dawn without snoozing the alarm over and over. Or you may, like one third of the British population, describe yourself as a ‘night owl’. For night owls, and I include myself in this category, mornings are a form of pure torture and much caffeine must be consumed before anything even vaguely resembling productivity is achieved.
Unfortunately for many, we live in a ‘nine till five’ society and we cannot always choose to work when we are most productive. New research from the University of Exeter published in Nature Communications can’t do much to change our inherent preferences but it can shed some light on why we fall into these two categories. So what determines whether someone is a morning or evening person? Well, it turns out it’s all down to your genes.
This isn’t completely brand-new information; previous research had identified a total of twenty-four genes that determine the way the human body clock is regulated which is known as our circadian rhythm. In 2017, three biologists won the Nobel Prize in medicine for discovering the ‘period gene’ which encodes a protein at night time, letting our bodies know that it is time to sleep, and which then degrades during the day.
The new Nature study brought the number of known genes from twenty-four to 351. Michael Weedon, a bioinformatics at the University of Exeter Medical School who led the study explained:
“Depending on how many of those genes you carry, you can be anywhere on the scale of ‘morningness,’.
“But our research showed that the top five per cent with the most of those 351 genes go to sleep on average 25 minutes earlier than the five per cent who carry the least.” (Wired)
So it turns out there are 351 reasons why you could get tired early, or on the contrary feel more productive once night has fallen, and there is not much you can do about it, because it’s all genetically predefined.
In addition to discovering more genes related to circadian rhythms, the study also looked at where those genes are most likely to be switched on in the body. Lead author Samuel Jones from the University of Exeter Medical School explains that different parts of our bodies carry different types of tissue. And while all tissues contain all of our genes, all of our genes are not switched on in all of our tissues.
“The genes we found to be related to our circadian rhythms tend to be switched on a lot more in the brain and in the retina. This helps us map what parts of the body are important in creating morning and evening people.”
Jones explains that these genes being activated in our brains is not surprising as it is already well-known that the brain is our body’s ‘master clock’. This clock is located in a zone of the hypothalamus called the suprachiasmatic nucleus (SNC). The SNC contains an oscillator that is thought to set your body on the time of the day in response to different signals it receives from the environment that you are in.
One of the signals that the SNC works with is light. For example, when the retina signals that it is night time, our brain releases a sleep-inducing hormone called melatonin. This is why Weedon and Jones’s research is so significant as it localises ‘morningness’ genes in the retina. So the way that we process light signals, and therefore the way that we signal, or not, to our body that it is time to sleep, could all be down to genetics.
Two of the genes found by Weedon and Jones had mutations which potentially alter the way the gene works to detect light. Jones said:
“We did know that light levels were used to train our body clocks but we didn’t know that the way we detect them could differ between morning and evening people. This shows that these differences could be happening at a fundamental level – the genetic one.”
So what difference does all of this make if you have no control over whether you are a morning person or a night owl? Well, evening people have already been widely associated with a variety of mental health conditions such as depression and schizophrenia. Last year, a report found that chances of having depression, a bipolar disorder and of being lonely are all increased for those who reported higher levels of activity at night.
But how do we know if mental health issues cause people to have disrupted sleeping patterns or vice versa? Jones explained:
“Genetics always come first. So this helps us understand which is the cause in the relationship between circadian rhythms and disease.”
Things may not always be this clear cut as some diseases like schizophrenia also have genetic roots. However, according to Jones it is safe to say that you are genetically predisposed to being a morning or evening person, and that this will then go on to affect your risk of mental health issues.
It may be that mental illnesses arise more frequently in night owls due to the mismatch between our nine till five lifestyle and this genetic predisposition. Fighting against your genetics can’t be good for your mental health and the question of whether this could be a contributing factor will be the focus of the researchers’ next study.
This research could be vital in creating a future society where more flexible working policies are implemented due to an understanding that people work better at different times of day. This could potentially boost productivity, but most importantly, it could improve workers’ mental health.
These are still long-term goals but they do bring hope for us night owls who hit that 4pm dip and fight tirelessly against the urge to nap. If you would like to determine whether you are a morning person or night owl, you can try the Munich Chronotype Questionnaire, dubbed as the “gold standard” by Weedon for assessing which category you fall under. It may not be enough to convince your boss that your work pattern needs altering, but it will satisfy your personal curiosity.