Since I got caught up in the fitness tracker craze, I’ve been paying more attention to how much and how well I sleep each night. I’ve also been doing some research into how I can improve my sleeping habits and whether my fitness tracker actually knows when I’m asleep.
In the process of all this reading and experimenting with sleep, I’ve come across a few different myths about sleep that I used to believe were true. In fact, some of the most common ideas about sleep are wrong, or at least misunderstood.
I picked five sleep myths that I think are fairly widely believed and gathered together the research I’ve found about why they’re wrong.
Myth 1: Teenagers are lazy
You’ve no doubt come across this one before, whether as a teenager yourself or as an observer. It’s common “knowledge” that teenagers, on average, tend to sleep in late and stay up late, no matter how many people tell them to stop being so lazy.
In fact, this is actually a totally natural thing. See, we all have this built-in body clock called a circadian rhythm. Our body clock is a small group of cells made up of unique ‘body clock’ genes, called the suprachiasmatic nucleus. These cells turn on and off and tell other parts of the body what time it is and what to do. Neat, huh?
Obviously, sleep is one of those things our body needs to match up to the time of day. One way it does this is to keep track of the sun to work out when it’s daytime and when we should be getting sleepy because the sun has gone down (this is why adjusting your light exposure is the best way to adjust to jetlag).
Our body’s natural inclinations to sleep change as we age. Obviously babies need to sleep a lot, and as we grow up we stop taking afternoon naps (at least, some of us do) and sleep for shorter periods.
What’s really interesting about teenagers is that during this age period, our body clocks run later than any other point in our lives. So when a teen is inclined to sleep in late and stay up late, they’re actually just listening to their body’s natural tendencies.
It’s even been found that adjusting school to start later can help students to get more sleep and feel less tired during the day. So maybe we need to lay off the teens and they’re night-owl habits (they do plenty of other annoying things we can nag them about, anyway, right?)
Myth 2: Old people need less sleep
When my grandmother told me she got up at 5am most mornings, I added “no more sleeping in” to the list of old-age horrors I expected to grow into. I assumed that getting up at 5am happened because the older you get, the less sleep you need. In fact, this is a pretty prevalent myth about old age.
The truth is, however, as we age, we tend to need roughly the same amount of sleep. Circadian neuroscientist Russell Foster explains in this TED talk that the reason we sleep less as we grow into old age is actually that it’s harder to stay in a deep sleep.
Myth 3: Naps are only for kids
Aha! You thought napping was for lazy people and kindergarteners, did you? Or you’ve been napping all these years, secretly knowing that you had one-up on everyone else who thought that (good for you).
Well, the secret’s out. Napping is for everyone and has actually been proven to be really beneficial for adults. Research has shown napping can improve your performance on cognitive tests, making you more alert and focused because your brain’s “cache” of stored information has been cleared out and moved to long-term memory:
Research indicates that when memory is first recorded in the brain—in the hippocampus, to be specific—it’s still “fragile” and easily forgotten, especially if the brain is asked to memorize more things. Napping, it seems, pushes memories to the neocortex, the brain’s “more permanent storage,” preventing them from being “overwritten.”
Not only does this improve your memory of things you learned before you napped, but clearing out that short-term storage of information helps you to soak up more after your nap. So, if you’re planning on learning something new, you might want to try taking a short nap beforehand.
And if you’re not a fan of naps because they make you wake up groggy, don’t get disheartened: in some cases, sitting or laying down quietly without sleeping can benefit your memory just as well.
Myth 4: Pulling an all-nighter won’t harm you
It’s been a while since I crammed all night or stayed up to finish an assignment right before the deadline, but I’ve definitely done it more than once. And I can’t imagine being back in those situations and making the decision to sleep instead of cramming all night.
I wish I had, though. Maybe then I’d remember more of what I learned today.
The truth is, according to science, we’re likely to lose a lot of what we study if we don’t sleep. Sleep deprivation, even from a single all-nighter, “impedes our ability to concentrate, to pay attention to our environment and to analyze information creatively.”, according to sleep researcher Sigrid Veasey from the University of Pennsylvania:
When we’re sleep-deprived, we can’t integrate or put together facts.
Danish biologist Maiken Nedergaard did some amazing sleep research using mice, which found that during sleep the brain goes through a process of clearing out junk, essentially:
When the mouse brain is sleeping or under anesthesia, it’s busy cleaning out the waste that accumulated while it was awake.
The longer we spend awake, the more of this waste builds up in our brains, making it hard for us to concentrate or consolidate new information. Over long periods of time, the effects of sleep deprivation are even worse, as we develop a build-up of proteins associated with aging and neural degeneration when our brains lack the downtime to clear them out.
As Dr Veasey says:
We’re really starting to realize that when we skip sleep, we may be doing irreparable damage to the brain, prematurely aging it or setting it up for heightened vulnerability to other insults.
Myth 5: We all need 8 hours of sleep
Perhaps the most common sleep myth of them all is the eight hours rule. We all like a good, solid number to grab onto as a rule, even if we don’t follow it. Of course, our bodies and lifestyles are complicated and require individual routines.
As Russell Foster mentions in his TED talk, eight hours is simply an average. According to the National Sleep Foundation, adults need seven to nine hours of sleep per night. The Mayo Clinic recommends seven to eight hours. Both organizations point out that several factors can affect the amount of sleep you need to feel rested and perform well the following day, including age, quality of sleep and your lifestyle. The National Sleep Foundation even mentions that sleep requirements can differ depending on the population studied.
Eight hours isn’t a terrible general rule to start with, but experimenting is the best way to work out what’s best for you.
Lastly, it may help to keep in mind that we haven’t always slept for a solid eight hours. In fact, not so long ago it was the norm to have two separate segments of sleep overnight. Historical research has found hundreds of references to what was apparently common knowledge: first and second sleep, and the gap in-between:
During this waking period people were quite active. They often got up, went to the toilet or smoked tobacco and some even visited neighbours. Most people stayed in bed, read, wrote and often prayed.
During the late 17th Century, the idea of two sleeps began to fade away, and was all but gone by the 1920s. Historian Roger Ekirch attributes the change to street and home lighting, and nighttime activities becoming more fashionable—whereas before, the night had a bad reputation for attracting criminals and drunks, and little “legitimate” activity.
I’m not sure how big an adjustment it would be to try have two sleeps with a break in-between, but I might just give it a go. Either way, I’ll take more comfort in waking up during the night, rather than panicking that my sleep has been disrupted.