The science behind sleep

12 April 2022 - 2-3 minute read

We spend around a third of our lives sleeping. So why do we do it, what’s actually happening when we are asleep, and what exactly does it do for us?

There’s nothing quite like a good night’s sleep. What better feeling than waking up refreshed and relaxed, mind and body recharged, and ready to tackle whatever the day ahead has in store.

Yes, we know that getting enough sleep is essential for our wellbeing in many different ways. It helps our bodies remain healthy and stave off disease. And without it our brains cannot function properly, which can impact on our focus, concentration, and ability to process memories. But what we still don’t know exactly, is how.

Right up until the 1950s, most scientists still believed that sleep was simply a time when our bodies shut down and went into hibernation mode. Nowadays of course we know different. And although our bodies always require rest after a day’s activity, it is our brains which really do the hard yards during sleep.

What happens when you sleep

When you sleep your blood pressure drops, along with your heart rate, breathing and body temperature. Meanwhile your brain kicks into action, now free of all that complicated and energy-consuming need to process your vision. Instead, its focus turns to laying down memory, restoring your mental function, and helping your body both heal and grow.

But of course this doesn’t all happen at once. Because all sleep is not the same.

The stages of sleep

As anyone who owns a fitness tracker may know, there are four different stages to our sleep, from near wakefulness to a deep slumber. On a typical night, you will cycle through these different stages a few times each night:

• Stage 1 – Light sleep – the transition between being asleep and being awake.

• Stage 2 – Deep sleep – your body temperature drops and you become harder to wake.

• Stage 3 – Even deeper sleep – your body temperature drops even further, your brain uses less energy, and your muscle tone decreases slightly. Weirdly, if you’re a sleepwalker, this stage is when it will likely happen.

• Stage 4 – the famous rapid eye movement (REM) sleep. Your heart rate and blood pressure rises, your brain goes into overdrive, and you dream.

You may also wake up momentarily during your sleep cycles, although you may not remember the next day. Your brain has better things to do!

Less cons, more pros

Lack or constant interruption of sleep (for all you parents out there) can have many serious consequences. From grumpiness, dark circles under the eyes to feeling tired in the afternoon - or in more prolonged cases it can lead to depression, anxiety, sickness, or even death.

But enough about the negative angles. Let’s take a look at some of the positives of getting a good night’s rest:

1) Improves your focus

Sleep is important for a variety of brain functions. It helps you understand and solve problems better, helps you be more productive during your waking hours, and perform tasks to a higher standard. Studies show this is especially true in children and teenagers.1

2) Lowers your risk of weight gain

Although the link is still not clear, several studies show that poor sleep patterns can lead to obesity. Similarly, getting a good night’s sleep can also help to suppress appetite, meaning you feel the need to eat fewer calories the next day.2 Oh, and it can also improve your athletic performance, if that’s a thing for you.

3) Lowers your risk of heart disease

It’s a simple equation. High blood pressure is a major risk factor for heart disease, New Zealand’s single biggest killer.3 And if we don’t get enough rest, our bodies are not able to regulate our blood pressure as effectively.

4) Makes you more intelligent

Sleep is also linked to our social and emotional intelligence. Without adequate rest, we are less adept at gauging the feelings of others. In other words, we’re not able to empathise as well.

5) Prevents mental health issues

In numerous studies, poor sleep quality and insomnia have been strongly linked with mental health concerns such as anxiety and depression. So if you’re having trouble sleeping and have noticed a dip in your mood, be sure to seek medical advice sooner rather than later.

6) Boosts your immune system

Lack of sleep has been proven to impair your body’s ability to fight disease, including influenza and COVID. One recent study has also shown that getting enough sleep before and after a COVID-19 vaccination may actually improve its effectiveness.4

7) Keeps you alive!

As well as health issues, a good night’s sleep means you are more in control of your faculties throughout the day. In other words, you lessen the chances of an accident through impaired judgment. In fact in the US, the CDC has stated that staying awake for more than 18 hours is comparable to having a blood alcohol content of 0.05%. And after 24 hours, this can rise to 1.00% - that’s over the legal NZ driving limit!5

Remember, we may never know the entire science behind sleep, but it is definitely a vital part of your overall health and wellbeing. So if you’re ever in two minds about whether you’re getting your fair quota, always ask the advice of a qualified health professional as soon as possible. And don’t sleep on it.