The brain is truly astonishing, if you disagree with that statement it’s just possible you have never heard of circadian rhythms.
Your circadian rhythm is best thought of as a body clock, a 24-hour cycle that tells you when to sleep, get up in the morning and eat. In biological terms the clock is called the suprachiasmatic nucleus or SCN for short. The SCN is a tiny part of the hypothalamus which is situated directly above the pituitary gland in the centre of the brain.
Your body has a clock
Do you wake in the morning naturally or is it the result of a stark shrill from your alarm? If its naturally then this is your internal clock at work. Interestingly it can be pre programmed, you will have done this many time, waking before your alarm goes off for example. We are not talking about 10 minutes before, so accurate is your body clock you can wake 1 minute or even seconds before it is due to go off. Jet lag is an example of what happens when you disrupt the internal clock, your entire body struggles to adapt, affecting your ability to concentrate, eat, rest and sleep.
Interestingly Circadian rhymes exist in all living organisms, including plants. The external stimulus is natural light. However even without light the 24-hour cycle will continue, this has been evidenced by research with people who are totally blind. Although their circadian rhythms are often said to “free run” and extend slightly longer than 24 hours, they continue independent of light.
Why is this important for studying?
One of the reasons for going into so much detail is to illustrate how complex we are as human beings and that what may seem a relatively small change in your behaviour e.g. studying late into the night, can have a significant impact on your ability to function, in this context concentrate and remember.
Pulling an all-nighter to prepare for an exam is a badge of honour that many students will wear with pride. It is perceived as a measure of how committed and mentally tough you are. And on one level the effort and difficulty of the task should be rewarded, but given that examinations are a test of cognitive ability anything that reduces your chances of doing well should be avoided. If Hussain Bolt ran the 100 meters in a record time, having been out on the town the night before, waking up with a hangover and only having two hours sleep he would be a hero. But if he lost, he would be a fool. Why would someone who had invested so much of their time put that at risk?
In simple terms you need to help your brain perform to the best of its abilities.
Circadian rhythms and memory
A little more technical detail to illustrate a simple point, if you don’t follow your natural sleep patterns your ability to memorise and retain information will be affected. Retention appears to hinge on the amount of a neurochemical called GABA which inhibits brain activity. And it is the Circadian clock that moderates the amount of GABA produced. In fact, in an experiment using hamsters where the circadian clock was effectively disabled the hamsters were unable to remember anything.
There is a far more sinister side to the disruption in your circadian rhythm, ongoing research has identified a direct link with mental health disorders such as depression. This is of particular interest given the rise in reported levels of depression amongst students. One area that is being investigated is screen time be that mobile phones or computers. The artificial blue light emitted from these devices could well be confusing your circadian clock.
Why we sleep is still uncertain but it is believed that deep sleep helps the brain consolidate all the experiences from the day, including what its learned. When you shut down your computer, it may say “do not turn off during this update” – that sounds like good advice.
And if you would like to find out more