Reading Time - 7 Minutes
Sleep is a important part of everyday life. In fact, it’s so important it’s necessary, and sleep deprivation studies on rats and dogs have shown that extreme sleep deprivation can be fatal.
For most people, sleep involves a single daily sleep event 5 to 9 hours in length, usually at night. Some cultures though, such as the Spanish culture, have a biphastic sleep schedule, where the afternoon siesta is a respected activity and a way to cool off during the hot afternoon hours of 2 to 5 pm, and then a longer 5-6 hour sleeping window occurs at night.
In the U.S.A, Gallup Polls show that American’s are on average getting only 6.8 hours of sleep per night, less than the scientifically recommended 8 hours. In fact, 65% get less than eight hours, and 40% get less than seven hours of sleep per night. The consequences of this lack of sleep are startling too. Neuroscientist from University of Western Ontario’s Brain and Mind Institute came to some concerning conclusions regarding the impact chronic insufficient sleep can have.
In a massive study with over 100,000 subjects, the researchers observed that cognitive performance is impaired in people who deviate from the recommended 7–8 hours per night. Sleep duration, either too much or too little, had little impact on short-term memory performance, hence why once you get up and moving after a short night’s sleep, you typically feel fine. Reasoning and verbal skills though were heavily impaired by too little (or too much) sleep. In fact, those who self-reported sleeping less than 4 hours per night had lower scores and similar cognitive performance of people 8 years older then them. A short sleep duration is also associated with a bunch of other negative consequences. In persons sleeping less than 8 hours, reduced leptin and elevated ghrelin hormones were observed in one study with 1000 subjects. This skewed leptin/ghrelin ratio has been found to be responsible for increasing appetite and hunger cravings. In fact, an increased BMI was found to be proportional to decreased sleep! Moving beyond specific negative health consequences, a meta-analysis of 16 studies found that sleeping for less than 7 hours per night conferred a 12% greater risk of death.
Take Control of Your Sleep
With sleep insomnia, poor sleep, and sleep deprivation being such a common occurrence and annoyance of modern life, it’s important to devote time towards learning and improving your ability to sleep, whenever, wherever, and however. Life is chaotic and often things do not go according to plan, so it is intelligent and advantageous to learn how to sleep for different lengths of time during the day. Armed with sleep skills, when the opportunity presents itself for some quick shuteye, you can capitalize on it. The three most beneficial sleep durations (and one bonus) outside of the standard 7-9 hour window are 15 minutes, 30 minutes, and 90 minutes. Master falling asleep fast and for these set lengths of time to develop a more flexible sleep strategy schedule, improving your health and life in the process!
15 Minute Nap
The 15 minute nap is one of the ultimate life hacks. Feeling drowsy, fatigued, or have brain fog? Sneak away for 15 minutes, get some shuteye, and and come back feeling refreshed for 1-3 hours. The secret of the 15 minute nap is that it drops you immediately into stage-2 sleep (as you can see above) after about 1-5 minutes of frequent transitioning between wakefulness and stage-1 sleep. That frequent transitioning is actually your bodies way of ascertaining whether it’s safe to sleep. In the stage-2 sleep phase, memory consolidation occurs, and mental performance is increased. It’s a mini tuneup for the brain! Upon waking, it’s been studied that the improvements in cognitive function are nearly immediate. This immediate increase in mental performance is possible because a 15 minute nap creates almost zero sleep inertia, like longer periods of sleep do. Sleep inertia is a state of reduced conscious mental performance that exists after you wake up as you transition from the long brain wavelengths of deep sleep to the short brain wavelengths characteristic of being awake.
The 15 minute nap is the best sleep option to utilize when you only have 15 minutes in the near future to catch some rest, and/or you require a cognitive boost right away.
30 Minute Nap
If you have longer than 15 minutes but less than the 90 minutes required for a full sleep cycle, then a 30 minute nap is a great option to improve mental clarity and also remove some physical fatigue. And it’s been researched too! A NASA sleep study found 30 minute naps enhanced performance by 16% in median reaction time and increase overall alertness by 34% during lapses compared to the no-rest control group.
The way a 30 minute nap provides a mental and physical benefit is the sleep stages you go through in the first 30 minutes of sleep. 30 minutes takes you to the final phase of stage-2 sleep, right as you’re about to descend into stage-3 deep sleep for a full 30 minutes (see hypnogram above). A 30 min sleep period transitions you in-between stage-2 and stage-3 sleep, so you receive some of the benefits of stage-3 deep sleep (fatigue lifting) but overall stay in stage-2 (mentally boosting). After 30 minutes has elapsed, it’s best to wake up or wait till the full 90 minutes required for a complete sleep cycle. Unless you’re specifically trying to practice improving your ability to wake up from deep sleep quickly (might be desirable for a soldier), then waking up during deep sleep isn’t advantageous in most situations.
90 Minute Nap
The 90 minute nap is special because it encompasses one entire sleep cycle, from stage-1 and stage-2 sleep, through stage-3 deep sleep, and finally to REM sleep. If you need the biggest physical and mental boost midway through the day, or in an extreme situation, a 90 minute nap is the way to go. 90 minute naps have been show to have a performance benefit up to ten hours later. The drawback of the 90 minute nap compared to the 15 and 30 minute options are that it creates more sleep inertia. Luckily, going through the sleep stages all the way to REM sleep takes one relatively close back to wakefulness, and therefore the sleep inertia upon waking is relatively minor.
BONUS - Hypnagogic Nap
Hypnagogia is the experience of the transition from wakefulness to sleep. Ranging from a few seconds to a few minutes, this transition period takes people from conscious to unconscious experience, and unusual sleep phenomenon such as lucid dreaming, hallucinations, and sleep paralysis can sometimes be experienced during hypnagogia.
A hypnagogic nap is a nap that only lasts for seconds. To experience a hypnagogic nap without having learned to control the hypnagogia state, sit in a chair and hold an object such as a metal ball in your hand and try to fall asleep. Right before you’ll fall asleep, your hand will relax, dropping the ball, waking you up from the hypnagogia state. With practice, the balls will no longer be needed. Visionaries such as Albert Einstein, Benjamin Franklin, Nikola Tesla, Ludwig van Beethoven, Salvador Dalí, Isaac Newton, Thomas Edison, Aristotle, and more all have credited hypnagogic naps with boosting their creativity and insight. I personally can attest to this phenomenon. All of my best ideas and revelations come to me as I straddle wakefulness and rest, and I’ve found that if I transition back to wakefulness instead of sleep after experiencing hypnagogia, I feel rested with my mind firing at max creative capacity.
Sleeping is an Advantage, Use it!
As I have covered lightly, it is clear that sleep is a critically important component towards achieving optimal human health, for achieving mental clarity, and for healing your body. Modern human culture hasn’t yet realized the importance of adequate sleep, and hasn’t made it easier to get the 7-9 hours needed, so instead your next best bet to achieve the optimal amount of sleep is to increase your sleep flexibility. Practice taking 15, 30, and 90 minutes, and soon you’ll be able to find ways to catch some shuteye in any situation.
Stefan Burns is the creator and main author of Wild Free Organic. A swimmer in high school, soon afterwards he discovered a passion for the health, wellness, and fitness fields. Stefan is a jack of all trades, expertly knowing how to use all the different wellness “tools” available to radically and permanently transform one’s health, from fasting and sauna usage to calisthenics and powerlifting.