It seems to be a popular belief that eight hours is the ballpark for a good amount of sleep. Whether you’ve discussed it with a medical professional, read it online, or heard it from a friend or family member; it’s almost guaranteed that you’re familiar with the “eight hours of sleep” rule. However, despite the prevalent belief, many experts have recently challenged this idea mostly based on the notion of individuality.
If the foods we consume, the energy we exert and the practices we engage in daily differ so greatly, how could it possibly be that all individuals require the exact same amount of sleep? You’ve probably guessed by now, and the answer is, it’s likely that we don’t!
THE SCIENCE OF SLEEP
If you’ve read our previous blog on sleep and mental health, or happen to have done your own research on the importance of sleep, you likely know just how engaged our brains are during the process. Aside from the relief of both physical and mental exhaustion, hormones (which impact almost all of our bodily functions) are released,
and complex processes like memory consolidation occur, just to name two of the many.
There are two cycles that occur repeatedly throughout the duration of sleep, being: REM (rapid-eye movement) sleep and non-REM sleep. We start off with non-REM sleep which consists of three stages:
1. Light sleep is the stage between being awake and being asleep, our muscle activity starts to slow down and we are technically only half asleep.
2. True sleep occurs next, when the body temperature drops and heart rate and breathing regulate.
3. During deep sleep, our breathing and heart rate are at their lowest and the brain begins to produce large but slow delta waves. We engage in rhythmic breathing and have limited muscle activity.
After these three stages, we finally enter REM sleep. In REM, our breathing and blood pressure are at their highest and despite our brains being very active and our eyes moving rapidly, the rest of the body is essentially paralyzed. This is where our dreams occur, and one of the reasons behind the virtual bodily paralysis is the prevention of acting out our dream.
This entire cycle takes approximately 90-110 minutes, and we supposedly need to go through between 4-6 sleep cycles per 24 hour period.
WHY DO SLEEP NEEDS DIFFER
Understanding the sleep cycle is just the start of understanding why sleep needs differ so drastically. As I mentioned, the average person goes through 4-6 sleep cycles a night. Assuming that someone goes through four, and it takes 90 minutes for them to go through a sleep cycle, that would only give them 6 hours per night. So even according to the science itself, it doesn’t seem like 8 hours is an absolute must.
Another clear inconsistency lies within the statement “per 24 hour period.” According to this, one could sleep very few hours at night, but make up for it during the day. However, experts seem to agree that a healthy nap shouldn’t surpass 30 minutes. But as we know, it takes 90 minutes to go through a sleep cycle. In summary, the science itself seems to be quite inconsistent.
Looking past the sleep cycle though, there are endless reasons why one may require more or less sleep than 8 hours. Individuals who suffer from medical conditions such as autoimmune or chronic illnesses are likely to require more sleep than those who don’t. Similarly, those who engage in laborious jobs which require far more physical exertion than lets say, a desk job, would likely also require more sleep, simply due to the body requiring more time to recover. Many other groups would also require more time to recover. Athletes, as you can imagine, have their entire career depending on their physical performance, and would definitely benefit from sleeping more than the average individual.
Aside from these differences, there is one recent scientific finding that very clearly answers the question of why some people require less sleep than others. Recent advancements in data on sleep genetics have identified a genetic mutation allowing individuals to feel fully rested with 4-6 hours per night. This gene mutation benefits certain individuals by making them natural “short sleepers” that can thrive in a similar way to those who require eight hours off of very few hours of sleep.
HOW DO I KNOW WHAT I NEED
If you’re basing your sleep schedule strictly off of expert recommendations, you may need to re-evaluate. Knowing that certain people thrive off of less or more sleep than others do, it is important to be mindful of your own needs and focus on doing what feels good for your body. While there are many experts on sleep, there is only one expert on you. So long as you feel well rested and energized, keep at it! And if not, it may be time to re-evaluate and increase or decrease your hours.