In this post we will go into the science of sleep so we can use that time more efficiently and wake up refreshed. If you have not already, be sure to check out part 1 where I go over how to wake up early and not be miserable (blog post and YouTube video).
Why is Sleep Important?
You have all heard that you should get 8 hours of sleep a night. In reality the amount of sleep each individual requires varies and it changes with age. For most of you, 7-9 hours should be your target. People generally underestimate the amount they need. There are some people who naturally require only 6 hours of sleep or even less (super sleepers), but chances are that it is not you.
Doctors are taught in medical school how important sleep is for health, cognitive, and physical function, yet they are some of the worst offenders when it comes to depriving themselves of sleep. Guilty as charged. So rather than being a hypocrite and telling you to get more sleep, I will instead go over how to make those hours in bed go further. But for the sake of completeness, let’s briefly remind ourselves why sleep is so crucial and why sleep deprivation is bad.
Long term sleep deprivation has been linked to serious health consequences that you don’t want. These include hypertension, diabetes, obesity, depression, heart attack, and stroke.
Sleep deprivation has been strongly linked with decrease in attention capacity and working memory. There are other cognitive functions that show decline, such as reaction time, auditory and visuo-spatial attention, and serial addition and subtraction tasks. Sleep deprivation also increases rigid thinking and makes it more difficult to utilize new information in complex tasks requiring innovative decision making. We also know that sleep is crucial for memory consolidation, meaning making things stick around in your memory. Therefore it’s not surprising that sleep deprivation also effects long-term memory.
In a fascinating study conducted at Stanford, researchers subjected college basket players to a 5 to 7 week period of increased sleep. Participants obtained as much sleep each night as possible, attempting to spend 10 hours in bed, and the scientists measured their physical performance. After the sleep extension period, subjects had faster sprints, improved shooting accuracy, and scored better on assessments of physical and mental well-being.
How to Sleep More Efficiently
You now know the health, cognitive, and physical ramifications of not getting enough sleep. But let’s face it, you and I both know that you still won’t be getting 7-9 hours every night. So what can we do about it?
One of the most important concepts to sleeping better is understanding that quality is more important than quantity. Meaning getting 6 or 7 hours of high quality sleep will do more good than getting 8 or 9 hours of low quality sleep. Studies have shown that average sleep quality is more important than sleep quantity in terms of health, balance, satisfaction with life, and feelings of tension, depression, anger, fatigue, and confusion.
You are probably getting disturbed during your sleep and you don’t even realize it. Studies have shown that nocturnal noise, most commonly traffic noise, can fragment your sleep, even if you do not wake up or acknowledge it. It changes the amount of time spent in different sleep stages, increasing the amount of time in shallow sleep stages and decreasing the amount of time in deeper slow wave or REM sleep. This has significant effects on sleep quality and recuperation. Even though people are unconscious and do not notice these sounds while asleep, they can differentiate between nights with low and high degrees of noise exposure because they feel better after quiet nights.
In my own life, I have noticed periods where I felt amazing after 6-7 hours and times where I felt slow and groggy after 8 or more hours. The secret was sleep quality. Maintaining a routine and regular sleep schedule by going to bed and waking up at the same time made a huge difference for me. Sleeping in generally resulted in poorer sleep because 1) people in my house or apartment were up making noise which disturbed my sleep, even if I didn’t wake up or remember it and 2) sunlight crept into my room which also disrupts sleep quality. A simple solution to these problems would be ear plugs and a sleep mask or black out curtains (Amazon links).
Sleep occurs in stages, from stages 1, 2, 3, 4, and REM (standing for rapid eye movement), which is when dreaming occurs. When you first fall asleep, you begin at lighter stages of sleep and over time you go deeper and then cycle through them, spending more and more time in deeper sleep and REM.
Because of this, power naps should be a maximum of approximately 20 minutes. These are enough to get you into Stage 2 sleep, which helps you boost memory and creativity. Longer naps are subject to increased sleep inertia, meaning it sucks waking up. If you nap for 30-60 minutes you will enter slow wave sleep, which is good for decision making, but you will wake up groggy. REM sleep occurs at60 to 90 minutes, but again you will wake up groggy. Therefore shorter power naps are your best bet.
Taking naps that are too long won’t only leave you feeling groggy, but will also decrease the sleep debt necessary for sleep onset. That means it will be more difficult for you to fall asleep at night.
Another interesting concept is coffee naps. Drink a cup of coffee, then take a nap for 20 minutes. By the time you are waking up, the coffee has been absorbed by the small intestine, passed into your blood, and is carrying out its effects in the brain. Some studies have even shown that coffee naps demonstrate improved cognitive performance compared to naps alone.
While coffee naps are a good idea, consuming caffeine before bedtime is not going to do you any favors. Caffeine shortens stages 3 and 4 of the sleep cycle, which are deeper stages of sleep. Studies have shown that caffeine even 6 hours before bedtime have significant effects on sleep disturbance.
Alcohol may help you fall asleep faster, but the quality of sleep suffers. It does technically increase slow wave delta sleep patterns, which is good. But it also increases alpha activity, which generally occurs when you are resting quietly. Combined, alpha and delta wave activity in the brain translates to poorer sleep. It also blocks REM sleep, which is considered to be the most restorative type of sleep. It also doesn’t help that it’s a diuretic and you’ll be waking up to use the bathroom more frequently.
What do you find helpful for obtaining high quality sleep? Leave a comment below!