4 Stages of Sleep & Why They Are All Important For Your Health
Sleep is an essential part of life, meaning you absolutely have to have it, and without it (eventually) you will cease to live.
While the scientific community has known about the importance of sleep for years now, the general public has taken a more callous attitude towards getting sufficient sleep each night, with many living by the motto of “I’ll sleep when I’m dead.”
And, rest assured, if you continue to shortchange your sleep, you will encounter a host of health problems.
Fortunately, thanks to new research, greater concentrations of the general public are starting to pay attention to their sleep hygiene and giving sleep the respect it deserves.
Sleep is a very complex subject, one which requires more than a single article to explain.
Rather than try to tackle all the ins and outs of sleep, today we’ll focus on the different stages of sleep you go through each night you hit the hay.
What Are the Different Stages of Sleep?
When you sleep, your body goes through two distinct phases every 90-120 minutes:
- Non-REM sleep, and
- REM sleep
Researchers organized the stages of sleep based on what takes place in both the brain and body during sleep.
The first major “phase” of every sleep cycle consists of non-REM sleep, which can be further subdivided into four separate stages:
Stage 1 of the sleep cycle is the lightest stage of sleep and occurs within minutes of falling asleep. Brainwave activity slows down slightly compared to when you are awake.
Breathing rate and muscle tone also remain relatively similar to their wake states.
As stage 1 is the lightest sleep stage, this is the stage where your body is still slightly alert and can most easily be woken.
Stage 1 also lasts relatively briefly, lasting at most seven minutes.
Stage 2 sleep is also considered fairly light, but a little “deeper” than stage 1, making it a bit harder to be woken. As you get deeper into the stages of sleep, your brain has a sudden spike in brain wave frequency, which is referred to as sleep spindles.
Once this brief spike of activity passes, brain waves slow down.
Note, for those of you who enjoy “power naps”, this is the stage of sleep you will likely wake up from.
Stage 3 & Stage 4 -- Deep Sleep
Stages 3 and 4 represent “deep sleep”, which are also referred to as “slow-wave sleep” or delta sleep.
In these stages, brain wave frequency slows considerably and eye movement is virtually zero, as is muscle activity. Stage 3 is the “deeper” of the two stages, as it is the hardest point of a sleep cycle to wake a person.
Should you be woken in stage 3, chances are high that you will feel groggy and somewhat disoriented. Basically, you’re not “with it” cognitively.
The way researchers discovered this was through the administration of cognitive tests to subjects being awakened during stage 3 sleep.
Within the first half an hour or so from being awakened, cognitive performance was worse compared to wakings from other stages of sleep.
As you continue into deeper and deeper sleep, the brain produces greater amounts of delta waves moving you into progressively greater restorative stages of sleep.
During this time, the body is doing the majority of its “maintenance work” -- growing, rebuilding, boosting immune function, and shoring up energy stores for the next morning.
After finishing up deep sleep, you progress to REM sleep.
REM, short for rapid eye movement, sleep is the stage of sleep most often associated with dreaming.
You enter REM sleep about 90 minutes after falling asleep, and each REM stage can last up to 60 minutes, though each of these phases can last for different durations depending on your age.
The average adult has five to six REM cycles each night.
During REM sleep, the body is much more active compared to deep sleep.
Eyes dart back and forth, breathing becomes faster, shallow and irregular, and both blood pressure and heart rate increase.
REM sleep is also when your brain integrates and processes what you learned during the day and readies it for storage in your long-term memory. What this means, is that if you are someone who is chronically sleep-deprived and missing out on REM sleep, you’ll likely run into problems with both learning and memory.
How Much Sleep Do I Need?
While some people will say they feel fine on 4-5 hours of sleep, research shows that only about 5% of the population carries the gene that allows an individual to survive and thrive on that little amount.
Generally speaking, most adults require a solid 7-9 hours of sleep a night to function at their best mentally, physically, and emotionally.
Every stage of sleep serves an important purpose in helping you feel and perform to the best of your abilities, yet many individuals struggle to get quality sleep each night.
To improve your chances of getting a better night of sleep:
- Set a sleep schedule and get to bed the same time every night
- Institute a nighttime ritual so that you give your body the signal it’s time to wind down for the evening
- Limit exposure or avoid “blue light” (tv, laptop, smartphones, tablets, etc) two hours prior to bed
- Keep your bedroom cool (between 65-68℉)
- Cut off your intake of caffeine by 3 PM
- Avoid alcoholic drinks immediately before bed
- Supplement with ZEN R.E.M., an all-natural sleep support to help balance hormones and recovery while you sleep.