Naps can make you sharper, but timing and duration are key

The Sleep Whisperer is a series of columns offering insights and advice about sleep health. It is not a substitute for seeking professional medical care.

At the University of Ottawa, where I work, I share my office with an emeritus professor who is heavily engaged in high-level scientific research while he is approaching his 80s. His secret? He keeps a foldable bed behind his desk and has been religiously napping almost every early afternoon since his teens.

For most people, naps can be beneficial. Think of them as a vitamin supplement providing an acute dose of the multiple positive biological processes that take place during sleep.

Recent research conducted at McGill University shows that if you have to pull an all-nighter, a 90-minute nap could help preserve your memory performance by 22 per cent by putting your brain in a state that is more conducive to absorbing new information. Naps can also boost your intellectual functions even if you have had sufficient sleep the night before. Benefits extend beyond memory performance; they also include improvement in alertness, mastering and refining skills, and ability to process information. Specifically, 20 minutes of shuteye is sufficient to increase alertness, though some research suggests that longer naps (at least 60 minutes) may more reliably enhance memory. An additional bonus is that naps can also lift your mood.

One thing to keep in mind, however, is that naps, especially the longer ones, can be followed by a period of sleep inertia when your mind stays in a slightly murky state for up to around 30 minutes. So if you’re planning a nap before that big exam or presentation, make sure to build in a buffer zone after waking up, as you can expect a time lag in your peaks in mental performance.

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Are naps right for you?

Despite their many benefits, naps aren’t recommended for everyone.

Of course, a daytime snooze may feel especially appealing when we don’t get enough sleep at night. However, caution should be raised for people with insomnia since naps reduce the sleep drive we build up during the day, which can take a toll on our nighttime sleep. In the context of chronic insomnia, naps can actually make things worse.

Also, if you feel constantly sleepy during the day, it could also be the sign of an underlying health problem. While napping might alleviate some of the impacts, they may be not resolve the root cause. If your daytime sleepiness is abnormally high, consult with your doctor.

That being said, naps can be useful tools for most people who do not have insomnia. For instance, it has been proposed that naps can help offset some of the effects of normal aging that make sleep shorter, shallower and more fragmented. And studies in older adults suggest that a midafternoon doze typically does not harm nighttime sleep. People who work night shifts or are travelling across different time zones, as well as parents with babies, may also gain a lot from napping.

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Getting the most out of your naps

Over all, unless you have recurring insomnia issues, naps are a natural brain and body booster that can help you perform at your best. Here is my little recipe to help you optimize the results.

Ingredients

The more sleep stages you can throw in the mix, the more diverse benefits you are likely to get. For example, during deep sleep, your brain is able to clean the neurotoxins that you’ve accumulated over the time you spent awake. This allows for better communication between brain cells, which helps you process information rapidly. Deep sleep and REM sleep also reinforce the connections needed to imprint what you’ve learned during the day. During lighter sleep, your brain produces sleep spindles, brief bouts of rapid brain activity that help strengthen memory traces. In other words, all sleep stages contribute to some element of intellectual functioning.

Preparation

Don’t expect to fall asleep as soon as you close your eyes. One challenge with napping is the pressure we often feel to drift off automatically, especially if we have only limited time before we need to get back up. Allowing yourself to simply relax and see what comes could help reduce performance anxiety.

Timing

We naturally tend to get sleepy in the early afternoon, during the “post-lunch dip.” This is a good time to take a nap. Conversely, if you doze off later in the afternoon or in the evening, you may not get enough time to build up sufficient sleep drive before your final bedtime. This makes it more difficult to fall and stay asleep at night.

Duration

There is a trade-off between napping for long enough to reap the benefits of all sleep stages, and diving into deeper sleep from which it can be more difficult to wake up. A 10-to-20-minute power nap can harness the benefits of light sleep while allowing an easy wake-up to resume the day’s activities. Yet, a 90-minute nap offers the chance to complete a full sleep cycle while smoothly transitioning to lighter sleep stages before waking up. Careful planning and using an alarm and can help you make the most out of your naps while waking up as smoothly as possible.

Dr. Rébecca Robillard, PhD, is a clinical neuropsychologist and associate professor at the School of Psychology at the University of Ottawa. She also leads clinical sleep research at the Royal mental health hospital. She co-chairs the Canadian Sleep Research Consortium, a national hub of sleep scientists and clinicians.