We spend a third of our lives sleeping, but do any of us really understand the process? Is there any point in sleep study or sleep tracking, or is it fine to close our eyes and drift into that sweet slumber?
The short answer is yes. Understanding sleep goes beyond knowing the benefits that come with a good night’s sleep. Just so you know, quality of sleep allows you to create a solid sleep schedule, maximises your time throughout the day and, most importantly, gives you enough sleep for the next day.
Sleep comes in different cycles and different stages. Each one of them has distinct and particular characteristics that affect our brain activity, body temperature and many other things.
Quality sleep, unlike what most people assume, is not based on the amount of sleep you get, but rather on the degree of relaxation that both body and mind get in a single night. Knowing the varying sleep cycles allows you to attain quality rest easier.
The science of sleep is a pretty uncommon topic, as most people tend to take sleep for granted, especially if they rarely struggle with it. However, with the right knowledge and approach, you can increase your total sleep duration and the rest you get from it. You’ll also decrease or prevent sleep disorders and boost your mental health.
In order for us to gain a deeper insight into what constitutes healthy sleep and to reap its benefits, let’s cover the different types of sleep.
Non-REM Sleep Stages
Also known as non-rapid eye movement sleep, the NREM sleep cycle is divided into three stages, known as NREM1 to 3. Usually, these stages are what we experience during the first half of the night, as they occur in intervals the moment we begin trying to sleep.
Stage 1
Specifically, NREM1 to NREM3 stages of sleep cover the early period of sleep, where our body begins to power down and prepare for sleep. Blood pressure and other functions slow down as the sleepiness begins to take hold.
The NREM1 stage is when you start to doze off into a less deep sleep stage where sounds or noises can easily wake you up. Some sleep scientists call this restful wakefulness, where the body is somehow aware of the outside world.
Stage 2
Next up is the NREM2 stage. This is the part of the sleep cycle where your body relaxes and loosens up. The brain exhibits signs of sleep spindles, which experts believe facilitate memory strengthening and disassociate the sleeper from outside stimuli.
Sleep spindles form at an early age, with infants 4 to 6 weeks of age already showing evidence of this occurrence, leading some to correlate it with cognitive development and maturity.
One other interesting note to consider is that as we age, our sleep patterns also adjust and, in a way, mature. For example, as we get older, we actually require less sleep.
Experts suggest that daytime napping contributes to this decline in sleep time, among other factors like health and lifestyle.
Stage 3
Coincidentally, the NREM3 stage is one part of the sleep cycle where ageing plays a critical factor. Studies have shown that the older we get, the less time we spend in this stage.
What makes this stage different? The NREM3 stage is the part of sleeping where the transition to the next sleep cycle happens, which we will discuss in detail later. Scientists believe that delta waves effectively usher in this change from light to deep sleep.
Another interesting fact about this stage is that men seem to get fewer hours of sleep in this cycle than women.
This stage is also the only part of the NREM sleep cycle that displays substantial, dreaming, which is often relegated to the succeeding sleep stage.
Light Sleep versus Deep Sleep
NREM1 and 2 are considered light sleep stages, while NREM3 is characterized by deep sleep.
Ask experts, and they will tell you that it is good to add as part of your sleep habits the goal of reaching deep sleep as soon as you can to transition easily into the REM sleep cycle, therefore spending less time in light slumber.
This is not to say that light sleep doesn’t have its merits. You’ll feel more rested and refreshed when you wake up from light sleep. In contrast, you’ll be sluggish and groggy if you start your day from deep sleep. Although reaching deep sleep is essential for rest, you also must finish the deep sleep and the next stage before you wake up to reap the benefits of light sleep.
Rapid Eye Movement or REM Sleep
Following the deep sleep stage is the REM sleep cycle, characterised by rapid eye movements and higher chances of dreaming, brought by increased brain waves, plus incidentally higher heart rates and body temperature.
As mentioned earlier, while deep sleep may allow for some instances of dreaming, it is in the REM stage where most of our dreaming takes place, usually around 2-4 hours in a normal sleep period.
So what does it mean for our body and brain? For starters, this stage sees an increase in breathing which might even lead to sleep apnea in some cases. This is also the stage where twitching of various muscles occurs, including the face, legs, and arms, in relation to our dreams.
A person with a balanced circadian rhythm and a regular sleep-wake cycle sees a relatively undisturbed REM sleep compared to individuals who suffer from sleep problems, lack of sleep, or some other health problem that leads to a compromised bedtime.
All in a Night’s Sleep
Getting your full eight hours of sleep every night is important, as this can help strengthen our immune system and general health and wellness. If you struggle to rest and stay awake at night, learning about sleep cycles may help you control and improve your sleep. With this knowledge, you’ll know better what to do to reach deeper sleep for a restful night.