Teens tend to be less alert in the morning. Those with a late chronotype – which includes most teenagers and young adults – will take longer to come round on a morning, they will want to sleep in longer and stay up later.
If schools and universities want to boost exam results, just set them later in the day – that’s the view of body clock expert Dr Gisela Helfer.
The University of Bradford bio-chronologist says moving exams to later time slots could help improve results.
Dr Helfer, who studies the body’s natural circadian rhythms, which are linked to light and dark periods of the day, says most teenagers and young people tend to be less alert first thing in the morning.
It all depends on something called your ‘chronotype’ – it is this that indicates whether you are a ‘early bird’ or a ‘night owl’. Chronotypes change throughout our lives but studies have shown that teenagers and young people are mostly late chronotypes.
Dr Helfer, from the University’s School of Chemistry and Bioscience, said: “Everyone is different but in general there are late chronotypes and early chronotypes. If you have an early chronotype, you will be what people call ‘a morning person’. You might wake up before the alarm goes off and be full of energy early on.
“On the other hand, those with a late chronotype – which includes most teenagers and young adults – will take longer to come round on a morning, they will want to sleep in longer and stay up later.
“When it comes to sitting exams, I think having an exam start at 9am is probably a bad idea for this reason, simply because most teenagers are late chronotypes, so it will take them longer to come around in the morning, whereas they will be more active later on in the day, in the afternoon and early evening.”
She added: “Chronotypes are being taken a lot more seriously, particularly in the field of sport, where some football clubs will even test their players for this. Chronotypes do change during the course of your life. So, typically, as you get older, you become more early than late. When it comes to students, however, as their body clocks are mostly late chronotypes, if I am setting an exam, I try not to do it at 9am.”
Circadian rhythms are often disrupted by the bi-annual clock change – in the UK, the clocks are due to go forward one hour on 27th March.
Dr Helfer is presently conducting research into a specialised group of cells in the brain called tanycytes, which are important in appetite regulation. The cells are located in the hypothalamus, which is also home to our body clock. It is this that synchronises rhythms throughout the body, making sure that all tissues work together at the right time of the day. When these rhythms are disrupted over long periods of time, this can lead to poor health.
It is not known how the clock and the appetite centres in the hypothalamus work together and why circadian disruption can lead to metabolic diseases but Dr Helfer’s research is actively looking at this link.
In the past, Dr Helfer has advocated scrapping the annual clocks change, arguing it effectively gives the country ‘jet-lag’ twice a year. Other side effects of the annual clocks change include more accidents at work and, according to one study, an increase in car crashes.
