Have you ever looked at your dog as she napped peacefully in the middle of the afternoon and felt intense jealousy? Unlike dogs and many other animals, humans are generally monophasic, not polyphasic, which means that they get most of their rest during one bigger chunk of time, rather than during multiple shorter periods. Essentially, this means that because of biology and society, we’re made to take fewer naps than our pets, according to Dr. Rajkumar (Raj) Dasgupta, MD, an American Academy of Sleep Medicine spokesperson and assistant professor of clinical medicine at the University of Southern California’s medical school. But there are exceptions to this monophasic rule — and perhaps the most important is the power nap.
What is a power nap?
Aside from being one of life’s most treasured productivity hacks, a power nap is a very specific kind of nap that you can use for an afternoon boost of productivity, and to help you become more alert and refreshed. “They can help out with memory, accuracy, and last-minute decision-making,” Dr. Dasgupta says.
How long is a power nap?
In order to get the “power” effect, you should only be napping for around 20 to 30 minutes. In order to be productive after your nap, you need to make sure that your sleep cycle isn’t making its way to the REM stage, one of the deepest, according to Dr. Dasgupta. If you go into the deeper stages of sleep that typically occur after 30 minute or so of being asleep, you can wake up feeling more tired and groggy than you did before the nap. This is called sleep inertia. The thing is, when we’re sleeping, our brain's inching its way through a multi-stage pattern that generally lasts 90 to 120 minutes. Some of the sleep stages in the cycle are lighter, while some are deeper. It generally takes between 70 and 120 minutes to achieve REM, which is associated with dreaming, Dr. Dasgupta says. “At nighttime, we want sleeping to be consolidated,” he says. “We want to get to deep stages of sleep at night — but, when we nap, we want to stay in the lighter stages of sleep.” These are referred to in the medical community as N1 and N2.
When should you power nap?
Dr. Dasgupta says that the best power naps take place around noon to 2 p.m. This is because the timing aligns with the circadian rhythms of most people. “If you’re someone who wakes during the day, and goes to bed at night, there are two times during a 24-hour period where humans’ circadian rhythms are tilted toward sleep,” he says. One is at night, and the other is mid-day. This is good information to have, but stealing a quick moment to close your eyes at 4 p.m. won't kill you. The most important rule for napping is to keep it “short and shallow,” Dr. Dasgupta says.
What about a caffeine nap?
If you want to kick this nap hack up a notch, high-functioning people around the world have perfected the caffeine nap, which starts with drinking a cup of coffee, tea, espresso, or swallowing a caffeine tablet. The next step is to immediately go into napping mode. Ideally, when you wake up from your brief slumber, the caffeine will have kicked in, and you’ll be raring to go. I first learned about this genius tip from former Miss America Savvy Shields, but Dr. Dasgupta gave me the official thumbs up that it can be a safe and effective restart to your day, as long as you're not over-doing it on the caffeine.
Are there people who shouldn’t power nap?
Power naps aren’t for everyone, specifically those who have a hard time sleeping at night, such as those with insomnia, Dr. Dasgupta says. “There’s the old adage, the more you're awake during the day, the more you sleep at night,” he says. “Napping taking away drive to sleep.” To recap, humans are monophasic, and are better off resting during one large chunk of time. “It’s how we function best,” Dr Dasgupta says. “Napping is not for everyone, and it can make insomnia worse.” If you’re napping during the day, you're going to have a harder time achieving that deep sleep and going through REM at night.
It's also important to take note if you're always tired during the day, even though you're sleeping a good 7 to 9 hours every night. This could be a sign there's an underlying issue that isn't letting you sleep deeply, and it might be smart to see a sleep specialist about this.