So what is exactly is sleep?
According to the Cambridge Dictionary, sleep is: "the resting state in which the body is not active and the mind is unconscious”.
We might appear ‘inactive’ when we sleep, but contrary to popular belief - sleep isn’t a time for the body to shut down and “rest”. In fact - it’s quite the opposite! Your brain and the cells in your body are extremely active when you’re asleep doing all the things that are key to good health, such as repairing your cells, boosting your immune system, clearing toxins from the brain, and even sifting through the day’s information you’ve absorbed, and storing long term memories. When we sleep we typically move through five different stages of sleep - also known as sleep cycles.
So what are the different stages of sleep we go through?
There are two key phases/cycles of sleep that our bodies go through - REM (rapid eye movement) sleep, and non-REM sleep.
Non-REM sleep has 4 stages (*or 3 according to some scientists) and REM sleep has one stage.
To break down the whole process ‘in a nutshell’, we go through stages 1,2,3,4, and then REM (rapid eye movement sleep). The cycle then repeats itself.
Stage 1 - This is the phase of light sleep when we’re just drifting off, but can be easily woken up (think about sofa naps!). We might twitch or sometimes get the sensation that we’re falling and then wake up. This phase is short and can last a mere 5-10 minutes.
Stage 2 - In this stage, our brain waves and eye movements slow down even further. It’s the stage where the body is getting itself ready for deep sleep - so your temperature drops, heartbeat and breathing slows down, and muscles relax.
Stage 3 + 4 - These stages are known as the ‘deep sleep’ stages. If you’re woken up during this stage, you’re likely to feel disorientated and groggy. This is also the stage that the body repairs itself, strengthens the immune system, and rebuilds muscle.
REM Sleep - This sleep stage is typically when we dream (roughly 90 minutes after we fall asleep). Our heart rate and blood pressure increases, our eyes move under our eyelids (hence the name - rapid eye movement), and our breathing may be irregular. Babies spend about 50% of their sleep in this stage, whereas adults only spend 20%.
What is a circadian rhythm?
A circadian rhythm refers to the (roughly) 24-hour cycle that the human body follows (according to the biological clock in our brain). It’s influenced by external factors (such as light and dark) as well as genetic factors. Your body makes you sleepy by increasing melatonin levels. These are switched off when the body senses light - which can explain why we find it hard to sleep when we’ve been on the laptop late at night.
What are the benefits of sleep?
Well firstly - we need sleep to survive, there’s no way around it! Going to sleep gives your body time to fix cells and repair itself - including your muscles and vital organs. The pituitary gland releases growth hormone, which in turn aids the body in recovery and growth.
Your immune system is boosted during sleep, and your sympathetic nervous system (which is responsible for the fight or flight response) also gets a chance to relax.
Research also shows that sleep removes harmful toxins from your brain that build up during the day. This process can actually decrease the chances of you getting Alzheimer's.(Source)
Sleep is also great for memory and learning - as your brain consolidates all your recent memories.
What happens if I don’t get enough sleep?
Not getting enough sleep can affect your mood, weight, immune function, metabolism, heart, brain, lungs, and more! It pretty much impacts every type of cell in the body! It affects your ability to make decisions, your memory, your focus, and your physical performance too.
There has been a lot of research into the link between illness and sleep deprivation such as:
1) High Blood Pressure and Cardiovascular Disease - A study showed that sleep deprivation was associated with elevated sympathetic nervous system activity, which could lead to higher blood pressure (Source) and potentially cardiovascular disease.
2) Immune System Function - A study concluded that sleep deprivation has a negative effect on the immune system as your body produces fewer antibodies that fight infections (Source).
3) Obesity - Research has also indicated the link between sleep deprivation and weight gain (Source).
4) Diabetes - Studies have indicated that people who slept fewer than 5 hours a night had a higher chance of developing type 2 diabetes (Source)
Which successful people believe in the power of sleep?
Jeff Bezos (founder of Amazon, and richest man in the world!) said in an interview: “Eight hours of sleep makes a big difference for me, and I try hard to make that a priority. For me, that’s the needed amount to feel energized and excited. If you shortchange your sleep, you might get a couple of extra “productive” hours, but that productivity might be an illusion. When you’re talking about decisions and interactions, quality is usually more important than quantity.”
Similarly, Arianna Huffington (founder of The Huffington Post, and Thrive Global) has even written a book called “The Sleep Revolution”.
In 2007, she collapsed from overworking, and this prompted her to look at the importance of stepping back from work, re-defining success, and prioritising sleep.
She famously said: “I studied, I met with medical doctors, scientists, and I’m here to tell you that the way to a more productive, more inspired, more joyful life is: getting enough sleep.”
Is there any wisdom in the phrase “I’ll sleep on it”?
Interestingly, during REM sleep, your body clears out clutter and information that’s not needed, so actually, it could explain why people who go to bed with a problem wake up with a solution!
What can influence the quality of our sleep?
Drinks that are high in caffeine (such as coffee), smoking, and high alcohol consumption can affect our sleep and cause insomnia, or less time in REM sleep. Additionally, blue light from our phones/laptops/electronic devices can affect our circadian rhythms and trick our brain’s into thinking it’s daytime.
How much sleep do we need?
There’s no solid rule to this, and it depends on our age, but the ‘sweet spot’ that most adults need is around 8 hours sleep to perform at their best.
The Sleep Association have put together this handy infographic which shows the sleep time needed by different ages.
What can I do to sleep better?
- Arianna Huffington suggests setting an alarm to go to sleep at night (just like you would in the morning to wake you up).
She also suggests: “Much of what keeps us from sleeping is the clutter in our minds, and the clutter in our physical space creates stress with visual cues that can keep the mind occupied by reminding us about what’s incomplete. So, as the U.K. Sleep Council recommends, de-cluttering your room can help de-clutter your mind for a better night’s sleep.”
In addition to this, here are some of our top tips:
- A warm bath with lavender can work wonders in relaxing you before bed, as can reading a book.
- Make sure your room isn’t too hot. We sleep better in cooler temperatures. Ideally, the temperature of around 16 to 20 degrees is perfect.
- Try not to go on electronic devices at least 2-3 hours before bed, or expose yourself to bright lights which can impact your body clock.
- Avoid nicotine, caffeine and too much alcohol late at night.
Sleep is key to survival - and many scientists believe it is just as important as food and water. Not getting any sleep can make you unwell, and also means your body can’t repair itself. So next time you're thinking of skipping sleep - remember the wonders it can do for the body and mind!
We'll leave you with this little mantra: