Do you get enough sleep? Do you experience daytime sleepiness? How long does it take you to fall asleep? Our nation has a huge, unnoticed public health problem: CHRONIC SLEEP DEPRIVATION!
I recently finished one of the most eye-opening books I’ve probably ever read: Why We Sleep by sleep scientist Dr. Matthew Walker. In the book, I uncovered some really eye-opening sleep facts that have made me question and change a lot of my habits!!
You guys. These sleep facts blow. my. mind.
This scientist backs everything up with high-quality research, and makes a super convincing argument that we NEED to and SHOULD start to prioritize sleep as one of our major health goals. Everything in this book is worth sharing, but I’ve boiled down the most surprising sleep facts for this post. The statements in this blog are backed by the research quoted in Dr. Matthew’s book.
There are two stages of sleep – Non-REM and REM (commonly known as “dream sleep”). Throughout the night, you rotate through NREM and REM sleep every 90 minutes.
Despite what you may have heard in the past – neither one is more important than the other!
Do you ever feel like you get worse sleep when you’re staying at a friend’s house, out of town, or at a hotel? There’s a reason.
For someone sleeping at home, their NREM brainwaves from one part of the brain to the other look very similar. But, if you look at the brainwaves when this person falls asleep a hotel, one-half of the brain stays a little more awake than the other. This makes sense from an evolutionary standpoint. When we’re sleeping in an unfamiliar environment, our brain senses that it should be a little more on-guard than at home. Preventing the full brain from entering the deep NREM sleep when away from home is a protection mechanism.
NREM sleep helps us transfer and store new information in our brain. REM sleep fuels creativity by taking these new memories and making abstract, intelligent interconnections.
They studied this concept by giving people a bunch of number problems. The catch, was that there was a hidden shortcut to all of the problems making it easier to solve them in shorter time. One group went home and slept overnight and returned to more of the same problems the next day. The other group took the first test in the morning, and spent 12 hours of the day awake, then retested. Almost 60 percent of the sleep group returned and (as Dr. Walker puts it) had the “ah-ha moment” in finding the hidden shortcut. This is compared to a measly 20 percent of the awake group.
Clearly, adequate sleep improves problem solving ability and abstract thinking, So if you have to make a major life decision, make sure to “sleep on it”!
Melatonin is probably one of the most common sleep supplements out there. What is it? Melatonin is a chemical released by the pineal gland in your brain at night. It tells our body that it is nighttime thus helping to regulate the timing of sleep. The concentration of melatonin slowly decreases overnight and shuts off in the morning. Unfortunately, melatonin supplements don’t really work in normal, non-jetlagged people.
When traveling across timezones, your brain may still think that it is daytime (even when it’s not). Your circadian rhythm will eventually adjust (per Dr. Walker, it adjusts 1 hour for every day you are in another time zone). You can help reduce jet lag by taking melatonin to trigger a rise in your levels when it truly is nighttime wherever you are located.
As we enter our senior ages, our circadian rhythm changes, causing an earlier bedtime. Melatonin also releases earlier in the night, but unfortunately, the brain releases LESS melatonin. Unlike younger adults, supplemental melatonin may help correct circadian rhythm in older adults, which then may reduce time to fall asleep, improve sleep quality, and reduce daytime sleepiness.
It’s not simply that teens need more sleep. Teenagers actually have a shift in circadian rhythm too, but in the opposite direction – forward. Their melatonin will not rise until about 10 or 11pm. So, unfortunately, no matter how much you argue with your teen to fall asleep, their late sleep cycle ain’t changing! On the same note, asking a teenager to wake up at 7 am is, according to Dr. Walker, the equivalent of asking you, an adult, to wake up at 4 am! Scientists suspect this difference in circadian rhythm is an evolutionary shift – to help teens transition into independence away from parents for a few hours.
Initially, this sleep fact seems obvious. But consider this: do you think 7 hours of sleep the night before a sports event is enough? Not quite. The LAST two hours of an 8-hour sleep cycle (specifically stage 2 NREM) is when your brain is bursting with something called sleep spindles. During this time, your brain takes the things you learned in practice and transfers them to motor memories. Basically, these motor skills will now flow more easily and effortlessly – almost like second nature. Cutting sleep short even by 1-2 hours a night will rob you of these benefits.
This goes to say that practice – with enough sleep – makes perfect.
A study showed that when completing concentration tests, the sleep-deprived people did just as bad as the legally drunk (0.08% blood alcohol) subjects. This is terrifying when you think of exhausted, sleep-deprived medical professionals.
Sadly, Dr. Walker reports that research indicates one in twenty residents will kill a patient due to a lack of sleep. Accreditation councils have created some limitations to overworking residents and students, like working no more than 24 hours nonstop. However, this still far exceeds any of the brain’s ability to function optimally. Plus, ask any resident, and they will likely tell you that these restrictions do not prevent the sleepless shifts from still happening.
The moral of the story – ask your doc how much sleep they got that night before.
Studies using driving stimulators showed that drowsy drivers performed just as bad as legally drunk drivers. Even more concerning, if you get behind the wheel with just 4 hours of sleep, you are almost 12 times MORE likely to get into a car accident. In fact, 1.2 million accidents are caused by sleepiness each year. As controversial as it sounds, Dr. Walker argues that drowsy driving is potentially more fatal than drunk driving, because when you fall asleep at the wheel (or have a “microsleep”) you stop reacting altogether.
A structure in our brain, called the amygdala, is responsible for triggering strong emotions. It is excessively reactive when sleep deprived. We also lose some control from the prefrontal cortex – a part of the brain that is normally our rational and decision-making center. We recognize sleep as a cause of crabbiness and emotional outbreaks in kids, but it’s true for adults, too.
One night per year, nearly 1.5 billion people are forced to cut back on sleep by 1 hour – daylight savings time. It is no coincidence that this lost hour and additional sleepiness causes the rate of heart attacks to spike the following day. Dr. Walker reports that it works both ways. In the fall, when we get an extra hour of sleep, the rates of heart attacks plummet the next day!
This sleep fact is one of the most relatable to my audience. Studies show that sleeping less than five hours per night causes an imbalance in your appetite hormones. The next day you feel constantly hungry and never satisfied. On top of that, you will experience a 40 percent increase in sugar cravings the next day. When you do eat sugar with more sleepiness, research shows people will eat 300 more calories than when well-rested. This adds up to an additional 10-15 pounds per year!!
Anyone wanting to lose weight wants to lose fat, not muscle! That’s exactly what adequate sleep helps you do. Research subjects that ate a lower calorie diet for two weeks were given either 5 or 8 hours of sleep each night. When sleeping 5 hours or less, the majority (70%) of the weight loss came from muscle loss! On the other hand, the well-rested subjects had 20% less muscle loss, and thus more weight loss from fat stores.
Perhaps the most interesting of the sleep facts for my male readers! Testosterone levels decrease when you are not well-rested. Surprisingly, this drop in testosterone “ages” a man by 10-15 years in terms of male vigor! If a planned pregnancy is in the future, you’ll want to make sure you (or your man) gets adequate sleep too, as sleepiness leads to a 29% lower sperm count than those with a full night’s rest.
Research shows that getting 7 to 9 hours of sleep in the week before getting the flu shot improves your response to the flu vaccine. Sleep boosts your immune system, and thus generates a more powerful antibody reaction to the shot (which is the whole point!). The sleep-deprived group had a 50% reduced immune response to the flu vaccine. So, make sure to fall asleep at an appropriate time and get at least 7 hours of sleep to make sure the vaccine actually worked!
Think back to a really scary or sad time in your life. Although it may bring up some feelings, it probably doesn’t bring the same heightened, emotional charge or stress as it did in the moment. During REM (dreaming) sleep, your brain shuts off your stress-related chemical, noradrenaline. At this time, REM sleep, and specifically the act of dreaming, actually helps to dissolve emotionally traumatic experiences from the day. Dreaming sleep activates the prefrontal cortex of your brain, which lessens emotional reactions.
This is one of the sleep facts that really hit home! I’ve heard about the effect of blue LED light on sleep but had NO idea of its impact. For example, compared to reading a printed book, reading on an iPad suppresses natural melatonin release by 50 percent. People using electronics before bed also lose significant amounts of REM sleep. Here’s the scary part – the study showed that people suffered from a 90-minute lag in melatonin rise for several days AFTER they stopped using the iPad before bed! Yikes.
But, wine makes me fall right to sleep! I know. I was shocked too. Alcohol doesn’t induce true sleepiness, but a sedative effect. According to Dr. Walker, it can hurt your sleep in two main ways. First, alcohol fragments sleep, meaning you wake up frequently throughout the night (even if you don’t remember). Secondly, alcohol strongly reduces REM sleep (which as we know, is mega important for problem-solving, creativity, emotional stability and more). Best to keep that glass of wine with dinner, and at least a few hours before sleeping so that it can start to make its way out.
The first important thing to say about this sleep fact is that prescription sleeping pills do NOT induce real sleep. In 2012, a physician named Dr. Daniel Kripke conducted a study examining more than 10,000 people taking sleeping pills. Controlling for other factors that may increase chance of death (like smoking, drinking etc.), they found that those taking sleeping pills were 4.6 times MORE likely to die in the nearly 3 year window. Sadly, even very occasional users of sleeping pills still had a 3.6 times greater risk of dying than non-users.
Researchers don’t really know why. But, some suspect higher-than-normal rates of infection, fatal car accidents, and higher rates of heart disease and stroke.
Adequate sleep is often disregarded in business. In fact, many wear this sleep deprivation as a badge of honor, interpreting it as hard work and dedication. But it may be hurting you. Laying down at night to fall asleep and getting at least 7 hours shows that it makes you a better employee! Luckily, businesses like Nike and Google are catching on, allowing flexible work schedules, and even incorporating relaxation rooms with “nap pods”. WHAT! How can I work there! ?
Remember sleep fact #4 that states teenagers have a later circadian rhythm? Well, sleep scientists argue and show that starting school too early may be hurting our kids. More than 80% of public high schools start before 8:15 am – many before 7:20 am – causing a disruption in their normal sleep patterns. One school in Minnesota moved start times an hour back and found that SAT scores increased by over 25 percent.
Another school that did the same test found a shocking 70% reduction in traffic accidents for 16-18 year old drivers!! Aligning high schools with the natural sleep rhythm of teenagers also leads to improved attendance, and reduces behavioral problems and substance abuse.
Saving one of the most popular sleep facts for last! A lot people suspect that doing more work at the expense of sleepiness will help you get ahead in your career. Sleep scientists say nope, wrong-o! For instance, one study showed that employees who slept more earned more money, on average. In fact, they found that an extra hour of sleep led to around 5% higher wages. Hey, we’ll take it!
While some situations obviously and unavoidably prevent good sleep (I’m looking at you, new parents ❤️), most of us can take the steps to prevent daytime sleepiness, improve our sleep habits, and enhance our health as a result!!