Did you know that about a third of your life is spent sleeping?
Some might think all that time in bed is a waste, but we need sleep, we can’t live without it (even if sleep deprivation is a drug).
We’re not just being lazy – there’s more going on inside our bodies than we know or realize while we’re asleep, so let’s talk about what’s really happening when we’re blissfully unconscious.
The Sleep Stages
Throughout the night, our brains move in and out of two different types of sleep:
- REM
- Non-REM
REM is an acronym for “Rapid Eye Movement.” In 1953, a physiologist and sleep researcher at the University of Chicago, Professor Nathaniel Kleitman, along with his student, Eugene Aserinsky, noticed that sleep characterized by rapid eye movements was connected to vivid dreaming whereas sleep without the eye movement wasn’t – resulting in the distinction between the two types of sleep, which we cycle through over and over throughout the night.
Non-REM Sleep – Three Distinct Phases (5-20 minutes each)
Stage 1
We’ve just fallen asleep, so while our eyes are closed, we can easily awaken since we’re just getting started.
Stage 2
We’re sleeping lightly, and our bodies are preparing for deeper sleep by lower both our body temperature and heart rate. Most of our night’ sleep is in this stage (about 45%).
Stage 3
Now we’re sleeping deeply and we’re very hard to wake up. If someone or something does manage to disturb use, we feel discombobulated. This Non-REM stage is the most important because it’s when our bodies work to restore, repair, and regrow, but we can’t get to this stage without the two prior.
REM Sleep – The Final Stage of Your Sleep Cycle (10-60 minutes)
Altogether, Non-REM sleep takes about 90 minutes and is followed by REM sleep – the first period is about 10 minutes, but as you continue to move through your sleep cycles, the REM stage increases in duration.
During REM sleep, both your heart rate and breathing ramp up. We also tend to experience intense and vivid dreams, though not everyone remembers them upon waking. While adults spend about 20% of their sleep in REM, babies can experience REM sleep for up to 50% of their sleeping hours.
What Our Bodies Are Doing During Sleep
Brain
Our cortex’s activity may drop 40% in Non-REM sleep, but it’s highly active during REM sleep. The blood flow increase in our brains during this stage is linked to memory and emotional processing, while blood flow decreases in complex reasoning and language.
Hormones
Sleep is an anabolic state (a time when our body conserves energy, repairs itself and grows), so hormones like adrenaline and corticosteroids drop because they aren’t needed while human growth hormone (HGH), melatonin, and sex and fertility hormones do the heavy lifting.
Immune System
It shouldn’t surprise us that when we’re ill, we crave (and need) more sleep because during sleep, the immune system ramps up production of disease fighting proteins and agents.
Plus, studies show that healthy sleep helps us fight infections and tumour necrosis factor (TNF), a cancer killing protein moves through our body during sleep.
Body Temperature
As we mentioned earlier, our body temperature drops during sleep (along with our metabolic rate) which helps us to sleep more deeply and give our bodies the opportunity to rest and repair
Breathing
Your whole body relaxes during sleep, including your throat muscles which narrow.
This narrowing is often the cause of snoring because the air has less room to flow and ends up vibrating your soft palate and uvula. But for many people, this narrowing of the throat results in an obstruction that interferes with your breathing during sleep (sleep apnea).
Why Sleep is Vital to Our Health
We all know that poor sleep leads to poor health.
In fact, people who continually sleep for less than six hours a night have short life expectancies.
But why is so important for our physical and mental health?
When we’re asleep, our bodies are working to help our brains function, process, and prepare for the next day; our heart and blood vessels heal and repair; our hormones and blood sugar are balanced; and our immune systems are strengthened. Without proper sleep, we can’t function properly when we’re awake and these consequences can occur…
But, if you’re going to bed and sleeping for 7-9 hours a night and still waking up feeling terrible and unrested, and having trouble with daytime sleepiness, you may have a sleep disorder like sleep apnea.- Difficulty concentrating
- Slow reaction times
- Faulty reasoning
- Daytime sleepiness
...All of which can be dangerous for your health and your safety.
But, if you’re going to bed and sleeping for 7-9 hours a night and still waking up feeling terrible and unrested, and having trouble with daytime sleepiness, you may have a sleep disorder like sleep apnea.
Sleep apnea symptoms can often be confused with other medical issues (especially for women), but typically include snoring, morning headaches, night terrors, waking up gasping, and excessive daytime sleepiness. Luckily, sleep apnea treatment is readily available and can alleviate your symptoms.
Our bodies do these things and so much more while we sleep (much that we know and even more that we don’t), so getting a good night’s sleep is crucial to your overall health and wellbeing. Practice healthy sleep tips like these, but if you’re not feeling recharged after a night of sleep, you may want to take our sleep quiz to gauge your risk for sleep apnea.
