How to Nap
Nap the Right Way to Boost Physical and Cognitive Performance
Napping can feel like such a treat. Yet there are ways to nap, and ways not to.
Personally, I love to nap. Particularly when I’m going through a busy time, a useful strategy is to take a nap about eight hours into my day. The sleep perks up my energy and focus for the rest of the day. Plus, it seems like a treat to take a break. There’s the brief cat nap approach, where you simply sleep where you are. The other approach is a full-on sleep session- changing into sleepwear, closing the shades, and napping in the bed. That’s my fave. When teaching, some of the most common questions are about naps. Should we take naps or avoid them? What’s the right time of day to nap? How long should a nap be?
Should we take naps or avoid them?
The research on naps is mixed, with pros and cons. Naps have been shown to improve cognitive performance for about two hours, particularly when taken by 1pm. A 20-90 minute nap for athletes will improve physical performance, perception, and psychological state. On the other hand, a large study found greater mortality in those who napped while having >6 hours of sleep nightly. It’s thought that the need for extra sleep can indicate chronic disease.
What’s the right time of day to nap?
The circadian rhythm of our core body temperature influences how sleepy we are. As core body temperature drops we become sleepy, and when it rises we wake up. At it’s peak, typically about 3 hours before our natural bedtime, we are most alert. The lowest core temperature is about 3 hours before we naturally wake.
There’s a dip in core body temperature about 1-2pm in the afternoon. This is why we often have a dip in our energy and alertness. This temperature dip makes early afternoon the time we most easily nap. Or, if we’re chronically sleep deprived, it’s the riskiest time for falling asleep unintentionally.
How long should a nap be?
Over the 90-110 minute sleep cycle, we go from light sleep to deep sleep, and back to light. Deep sleep, otherwise called slow wave or Stage 3 sleep, is when our brainwaves are very high amplitude and slow. This is quite different from our waking brainwaves. Therefore, waking from deep sleep will often have us feeling groggy, and take about 20 minutes to become fully alert and functional.
Therefore, a cat nap of less than 30 minutes is easiest to wake from, as it will have us waking from a lighter stage of sleep. Alternatively, take a nap that is a full sleep cycle, so we’re again waking from a light stage of sleep. This can be particularly helpful when for whatever reason you’re not getting sufficient sleep at night, and need to make up that sleep time.
A couple examples come to mind. One is for people who do early morning shift work. One patient was working a very early shift, from 6am to 2:30pm, which required waking by 5am. Going home to nap from 3pm to 4:30pm allowed her to have an active social life in the evening, with a later bedtime of 10-10:30pm. Combining her nocturnal sleep and nap she was well-rested and had all the benefits of sufficient sleep. For teens (the most sleep deprived age group), napping regularly can also increase their sleep total closer to the recommended amount. In our neighborhood, swim team and band meet before school, starting at 5:45 or 6:00am, making it impossible for teens to get enough night-time sleep. Having a nap regularly after school can increase alertness, performance and mood in the afternoon.
When napping is a problem.
Working in a sleep clinic, it’s common for people to come in because they’ve been falling asleep unintentionally at stop signs. This is a sign of such profound sleepiness that it’s unavoidable. If you are falling asleep unintentionally during the day, take immediate action to get help. Stop driving, and otherwise operating heaving equipment or doing activities where injury is possible. Set up an appointment at your local sleep center.
Napping later in the evening, particularly for a longer time, can discharge your sleep drive, and make it difficult to sleep later at night. It’s generally recommended to prioritize consolidated nocturnal sleep, and limit naps if they are causing nighttime difficulties.
Bringing it all together.
Napping can be a useful strategy, particularly when you are chronically sleep deprived, or your daytime experience is impaired by sleepiness. I hope these sleep skills help you, everyone needs a good night’s rest.
Sleep well and dream big,
Dr. Catherine Darley
References:
1. Dutheil F, Danini B, Bagheri R, et al. Effects of a Short Daytime Nap on the Cognitive Performance: A Systematic Review and Meta-Analysis. Int J Environ Res Public Health. 2021;18(19):10212. Published 2021 Sep 28.
2. Lastella M, Halson SL, Vitale JA, Memon AR, Vincent GE. To Nap or Not to Nap? A Systematic Review Evaluating Napping Behavior in Athletes and the Impact on Various Measures of Athletic Performance. Nat Sci Sleep. 2021;13:841-862. Published 2021 Jun 24.
3. Wang C, Bangdiwala SI, Rangarajan S, et al. Association of estimated sleep duration and naps with mortality and cardiovascular events: a study of 116 632 people from 21 countries. Eur Heart J. 2019;40(20):1620-1629.
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