and the art of napping. Let’s get straight to it.
The Sleep Cycle
First, the key in understanding napping is a familiarity with the science of the sleep cycle
. The groggy feeling you get post-nap is called sleep inertia, and it is linked to being woken during deeper stages of sleep. It goes beyond feeling drowsy, and also makes you disoriented and limits your motor dexterity. For surgeons, that’s a big no-no. Power naps
, however, exploit the lighter stages of sleep, specifically stages 1 and 2.
When you’re awake
, your brain activity is characterized by beta waves
, which are high in frequency and low in amplitude, and more desynchronous than other wave types. When relaxing but still awake, such as during meditation, our brain waves slow down, increase in amplitude, and become more synchronous – these are alpha waves
. Stages 1 and 2
of sleep are chracterized by theta waves
, which are even slower in frequency and higher in amplitude compared to alpha waves. In stage 2, theta waves are interspersed by sleep spindles
and K complexes
If you wake up during stages 1 or 2, you’re much less likely to experience sleep inertia. Longer naps subject you to the delta waves of stages 3 and 4
. These are the slowest and highest amplitude brain waves. This is the deepest part of sleep and is the most difficult stage to wake from. In rapid eye movement, or REM
, sleep, the brain exhibits higher activity, with alpha, beta, and desynchronous waves
, similar to a wakeful state. This is the state where dreaming occurs. While deeper stages of sleep and REM are considered more restorative, getting into these states during naps does not fare well.
By understanding the sleep cycle, it makes sense why we need to keep power naps shor
t. Napping for too long will subject you to deeper stages of sleep, and therefore sleep inertia. I recommend experimenting with the duration that best suits you. For me, I’ve found that 15 minutes is the sweet spot, and yours will also probably be similar. Start in the range between 10 and 20 minutes
and experiment from there. Twenty minutes is enough to get you into stage 2 sleep, which has been linked to boosts in memory and creativity. Crossing past 20 to 25 minutes is a very dangerous territory. Not only are you more likely to wake up feeling groggy, but you’re also much harder to wake, thus increasing the chances that your power nap will beome a 3 hour slumber.
Now let’s go over 4 concerns you may have and how to address each one.
Concern 1: I Cannot Fall Asleep That Fast!
A very common concern with power napping is that you don’t have enough time to fall asleep. To address this, I have two recommendations:
First, invest in some proper sleep gear
. Seriously, I bought an excellent sleep mask
and ear plug combo
for only $10 and I’ve never napped better. And not just a regular sleep mask, but a contoured one that keeps the material off of your eyes. It’s actually a total game changer. You can thank me later. By addressing external factors like ambient noise and light
, you are recreating an ideal sleeping environment, and your brain will be much more willing to relax into a power nap.
Second, don’t worry about “falling asleep”
. Just the act of getting into bed with your sleep mask, ear plugs, and relaxing will slow your brain down. That’s enough to get several benefits. My favorite naps are the ones where I feel like I haven’t even fallen asleep, and I get up a couple minutes before my alarm goes off, feeling energized and ready to tackle the rest of the day. Over time, you will condition yourself to associate the sleep mask and ear plugs with nap time, and you’ll find yourself falling asleep faster than ever. You may have to tweak your power nap duration at this point, as you may be falling into deeper sleep faster. I now personally go closer to 12 or 13 minutes since the sleep mask and ear plugs are so effective.
Concern 2: Oversleeping
The next concern is oversleeping
. I’m all too familiar with this. When you’re sleep deprived
, this is particularly dangerous as you’re even more tempted to hit snooze. To address this, you must minimize the chances of you hitting snooze. Don’t sleep with your phone or alarm right next to your bed. It’s too easy to hit silence and next thing you know, it’s 3 hours later. Rather, place your alarm on the other end of the room so that you have to get up to turn it off. My tendency to oversleep and hit snooze after a rough few days in the hospital was cured by this simple trick. While snoozing in the mornings isn’t a good habit, snoozing during a power nap is a much worse idea.
Concern 3: I Won’t Be Able to Sleep at Night
This is a completely valid concern, and is best addressed by being mindful of the time that you take your nap
. If you take your nap later in the day, the amount of sleep debt required for natural sleep onset that night may be disrupted. For that reason, I recommend limiting your naps to no later than 3PM
. This will, however, depend on multiple factors, including the particular time that you go to sleep. If you are ok with sleeping later at night, then you can nap a little later into the day. If however, you intend to sleep early, then you may want to stop napping even earlier than 3PM.
I have found that when I’m postcall from the hospital or in other periods of sleep deprivation, I can get away with naps later in the day without much detrimental effect on my sleep later that night. This is because the overall sleep debt is still quite significant.
Concern 4: I Still Wake Up Tired
If you still aren’t feeling as awake and alert as you would like, I have two recommendations.
First, check out coffee naps
. I’ve mentioned them before in my other sleep posts
, and they work wonders. The idea is simple. Drink a cup of coffee or take a caffeine pill, then start your power nap. By the time you wake up, the caffeine has been absorbed by your small intestine, entered your bloodstream, circulated, and begun working its magic. More specifically, adenosine
from consumed ATP builds up in your brain over the course of the day, and is one of the factors inducing fatigue. Caffeine competitively inhibits
this molecule, meaning it competes for the same receptors. When caffeine is blocking the adenosine receptor, you become more alert. For more on the science and tips on how to drink coffee effectively, check out my caffeine consumption post
Second, critically examine your sleep at night. If you’re sleep deprived, it’s probably due to being inefficient during the day
, resulting in you not having enough time to sleep. If you’re getting enough sleep but still feel fatigued, it could be a variety of things, but a great place to start is by improving the quality of your sleep
to feel more refreshed. Six hours of good quality sleep feels WAY different than six hours of poor quality sleep.
The elusive glory of the power nap has evaded fatigued students for centuries. Too frequently, you either wake up feeling groggy and worse than you did before the nap, or you oversleep and that 20 minute nap becomes a 2 hour nap. The struggle is real. We’ve all been there. As a recently minted medical doctor, I’m unfortunately familiar with