For some people, the slightest noise awakens them at night like the creak of a floorboard. But for others, the wailing siren of a fire truck doesn’t disturb their slumber. Just why, though, remains a bit of a mystery.
Although many people are self-proclaimed light sleepers or heavy sleepers, researchers have found that there is little actually known about why people react differently to noises and other stimuli during sleep.
Of course, genetics, lifestyle choices, and undiagnosed sleep disorders may all play a role. In addition, some studies suggest that differences in brain wave activity during sleep may also make someone a light or deep sleeper.
I think we all have a rough idea of what occurs when we sleep (excluding the Biology Department). But it is extremely important to have a deep understanding about the science of sleep because it will provide you with knowledge of how we sleep and what will support a good quality sleep.
Sleep does not act like a light bulb that is either on or off. There are four different stages of sleep that everyone goes through several times each night: varying from light to deep sleep.
These stages are made up of two types of sleep: REM (Rapid eye Movement) and Non-REM.
During Non-REM sleep, there are three stages: restful and restorative sleep where your body is being repaired. Non-REM sleep relaxes muscles and lowers body temperature, heart rate, and blood pressure.
In stage N1, you experience light sleep, where you are nodding off to sleep but can be easily woken by a slight sound or movement.
In stage N2, this is a deeper sleep, you are still aware of your surroundings but if left undisturbed, you will continue into stage N3.
In stage N3, this is slow wave sleep where you are in deep sleep and may find it difficult to awaken.
So, what about REM sleep? Rapid eye movement is where the body switches off, and the brain receives extra blood and processes the day’s events. This helps to support learning and the development of your social and emotional skills – in REM sleep you dream. During this period of sleep though, your body is paralysed, so you don’t act out your dreams.
It usually takes us around 90 minutes to cycle through the stages of sleep. During the first third of the night, we tend to have our deepest sleep. It is thought that this is the time when most of the body restoration and repair occurs.
Melatonin is a hormone that occurs naturally in our bodies when it gets dark. It’s produced at night-time to help us go to sleep. However, light of course is a common sleep ‘robber’ because when light signals enter the eye, this sends a command to the brain to stop producing melatonin.
This is why it is a good idea to go to bed in a dark environment and to dim the lights in the run up to bedtime as now, we have more exposure to artificial light than ever before. This disrupts our body clock which therefore keeps us alert which in turn makes us feel less sleepy.
In particular, melatonin production is interfered with by screen activities like watching television or reading on your phone. The light from the screens will stop the melatonin being produced as effectively, meaning your body won’t get the signal to help it feel sleepy and you may find it harder to get to sleep.
So clear take aways are go to bed at a good time – pulling all-nighters are not the way to go, especially on a school night (come on guys). Don’t let the last thing you see before you go to bed, be a device – why not just go straight to sleep or even do something relaxing on paper? (if you don’t like reading).
I hope you have learned something new about the clockwork of our bodies during sleep and so, I look forward to seeing you back next week for a new question and a new answer.
