Sleep plays an essential role in your mental and physical health. It’s also a fascinating physiological state that’s often surrounded by mystery and enigma. In ancient times, it’s been the topic of many beliefs and ideologies. Plato, for example, believed that dreams originated in the liver, while Aristotle professed it resulted from the soul leaving the body.
Modern-day cultures are not without their fair share of misled and misinformed beliefs. But separating facts from fiction is essential to ensure you tackle sleep health in the most effective way possible.
What exactly is sleep?
Before banishing sleep myths, let’s first explore what exactly sleep is, so you understand its physiological workings. According to scientists, sleep consists of repeated sleep cycles, each of around 90–120 minutes long. You could typically experience 4-6 of these during a night.
Each sleep cycle consists of 2 phases—non-rapid eye movement (non-REM) and rapid eye movement (REM) sleep. The length of non-REM and REM sleep is unique to each person based on a variety of factors like age and gender. For example, infants spend more time in REM sleep compared to adults.
Let’s briefly look at what happens in your body during these two important sleep phases.
Non-REM sleep
Non-REM sleep is the first stage of a sleep cycle. During the initial few hours of sleep, you typically spend more time in non-REM than in the REM state. It then reduces towards the early morning, where a longer time is spent in REM.
The Non-REM sleep phase is characterized by:
- Decreased brain activity.
- Slowed down eye movement.
- Reduced muscle tone.
- Slower breathing and heart rate.
- Decreased use of energy by the brain.
- Lower metabolic rate.
The non-REM phase comprises four stages where you transition from light sleep to a state of deep sleep called slow-wave sleep. During these four stages, the brain waves become slower and shift from theta to delta.
REM sleep
Rapid eye movement or REM sleep is the second stage of the sleep cycle. In adults, it takes up around 25% of sleep time during the initial few hours of sleep. It then increases in the later stage of your slumber.
Also called the paradoxical state of sleep, the REM phase is mainly distinguished by:
- Increased brain activity.
- Rapid eye movements.
- Loss of muscle tone.
- Irregular heart rate and breathing.
- Dreams and nightmares.
- Less restfulness.
When you wake up unprompted, it’s usually at the end of the REM phase and sometimes during it.
Quick Fact: Alpha brain waves that are typically seen when you’re fully awake and relaxed, also occur during REM sleep. So, although the body is in a state of paralysis during REM, brain activity in this stage is quite similar to that when you’re awake.
The Circadian Rhythm
The circadian rhythm regulates your natural sleep-wake cycle. This 24-hour process is what naturally brings about sleepiness and wakefulness during a specific time of the day.
Now, the regulation of your internal sleep-wake clock is affected by cues from light and darkness. It’s why you would feel more alert and awake as the sun rises and feel sleepy as night falls. This phenomenon may also cause sleep issues among individuals experiencing complete blindness as their circadian rhythm struggles to identify light cues.
Following your body’s natural sleep-wake cycle is important for sleep health. Disruptions to it could drive your mental and physical functions into turmoil. You can see this when you travel between different time zones or oversleep till noon during the weekend. However, the circadian rhythm could also change over time based on factors such as age.
Debunking sleep myths
Now let’s take a closer look at four common sleep myths and how science debunks them.
Myth #1 — Sleep without dreams is a sign of high-quality slumber.
According to research, everyone dreams during sleep, although some may have no recollection of ever dreaming once they’re awake. When you remember a particular dream or a part of it, it’s often because you’ve woken up during or right at the end of the REM stage. This is when most dreams and nightmares occur.
But keep in mind that it’s normal to forget a dream even when you wake up from REM. Sometimes, factors such as gender, health conditions, and medications could also affect your ability to remember dreams.
Myth #2 — The brain shuts down during sleep.
Your brain never stops during sleep. In fact, it’s hard at work coordinating various physiological activities—from consolidating your memories and coordinating cell regeneration to processing information to help make decisions when you wake up. And according to scientists, brain activity during REM sleep could resemble the levels found in wide-awake states.
Moreover, multiple studies have found that even certain types of learning can occur during sleep. For example, one experiment exposed a group of smokers to a cigarette smell together with the odor of spoiled eggs and fish while they were asleep. And the researchers noted that the participants had learned to associate smoking with those unpleasant smells even when they were awake. Similarly, studies have also found that you can learn to associate sounds with smell during sleep.
Myth #3 — Alcohol can help sleep better.
For years, nightcaps like brandy and bourbon were associated with a good night’s sleep. However, according to the National Sleep Foundation, alcohol consumption before bedtime might diminish your sleep quality. While it could certainly help sleep faster, it can also disrupt your circadian rhythm, reduce your REM sleep, and cause snoring and sleep apnea.
And the result? You could experience severe sleep disturbances and wake up feeling tired and restless. The more alcohol you consume before bed, the more intense these disruptions could be.
Myth #4 — You can catch up on sleep later.
Some people lose out on sleep by choice. According to a survey by the American Academy of Sleep Medicine (AASM), 88% of adults in the US have sacrificed their sleep to watch TV or a streaming series. Others like caregivers compromise sleep for their work. And many of them believe they can catch up on lost sleep. But according to science, this is far from the truth.
In fact, depriving yourself of adequate sleep for several days and sleeping excessively over the weekend to make up for it could severely disrupt your circadian rhythm. And it can lead to fatigue, inability to focus, and reduced performance.
Continued sleep deprivation can lead to what scientists call sleep debt. And you can’t pay it up with one or two long slumbers. It requires small increases in sleep over a longer period. In fact, according to research, it could take up to 4 days to recover from a sleep debt of just 1 hour.
Untangling the myths surrounding sleep is essential to develop smart and effective sleep habits. After all, sleep plays a central role in your mental and physical wellbeing. So, developing a sound understanding of it is essential for your long-term health.
