20-Minute Power Nap for Boosted Performance (#158)

A power nap is simply a shorter sleep period of 10–30 minutes (often around 20 minutes). The term power nap isn't new by any means, but it hasn't always been called that. You've probably heard of people from the previous generation, like granddad or grandpa, who always lay down for a quarter-hour nap after meals or took an "afternoon nap." It's definitely not a bad idea when it comes to alertness and mood (https://www.ncbi.nlm.nih.gov/pubmed/29851569).

But the question we ask is: does it have a performance-enhancing effect, and if so, in what situations? Research shows that a short power nap can improve performance when you've slept too little the night before, but it likely has little to no effect if you're already well-rested.

A study published in October 2018 in the European Journal of Sports Science examined how a group of well-trained, seasoned runners were affected by a "powernap" and how this effect correlated with their overnight sleep. The question is, can we determine if a powernap helps us perform even when we've had a good night's sleep? Research suggests that endurance athletes generally sleep around 6.5 hours per night during a training cycle, while the recommended sleep time for an adult athlete is between 7–9 hours.

Previously, there were two published studies that examined how a powernap affects anaerobic performance, i.e., above your threshold, often in the form of intervals, strength training, sprints, cycling tests, etc. The first study showed a performance-enhancing effect, while the second showed no effect. The difference between the studies was that in the study where participants experienced a performance-enhancing effect, they had only slept four hours the night before the test, whereas in the one that showed no effect, they had slept eight hours. The new study we are now going to explore aimed to combine these findings and test competent runners in a qualitative RCT study where all participants performed both tests in random order.

The participants included 11 males with an average age of 35 years and a VO2max between 50–70 ml/kg/min (average 60), running over 70 km per week. Each could run 5 km in 23 minutes or faster.

The setup was quite relatable for many of us: they completed a 30-minute morning run at 75% of VO2max, which is akin to medium-intensity commute running or a morning spin on the bike. This was done between 07:30 and 10:00. Then, they tackled a more challenging session in the afternoon between 16:00 and 18:00. This session involved a 20-minute warm-up at 60% VO2max followed by a short rest, and then running at 90% VO2max until exhaustion.

These tests were conducted either with or without a 20-minute (10–30 min) power nap around 15:00 in the middle of the day. On average, they lay in bed for 35 minutes, with 20 minutes spent sleeping. So, allocating half an hour in the schedule is beneficial if you're planning a power nap.

An initial review of the data showed that a power nap did not boost performance at the group level. However, when researchers analyzed the data based on how much sleep participants had before the tests, a clear trend emerged.

• Participants who slept an average of 6.5 hours the night before the test experienced improved performance from a power nap.
• The group that slept an average of 7.5 hours saw no additional benefit from a 20-minute power nap.

The study results suggest that you may enjoy performance gains from a power nap after a poor night's sleep. As shown in the image below, the percentage improvement is greatest for those who slept the least the night before. It even appears that a power nap can reduce performance if you take it midday despite having slept well at night—you might feel extra sluggish, similar to when you've overslept and feel groggy for half the day thereafter.

A scenario where this might apply is if you've cycled to work in the morning or had a light exercise session and are planning a high-intensity workout for the evening. If you've shortened your sleep the night before to fit in the morning activity without disrupting your routine, a midday nap of about 20 minutes, either during lunch or right after work, could restore your performance or even enhance it for the evening.

Participants who slept less at night and took a power nap performed better in the evening, reporting a lower RPE during the "time to exhaustion" test. Researchers suggest that the improvement might not be due to the body being physically more "prepared," but rather the mind felt refreshed and the workout felt easier, allowing them to continue for longer. This is discussed in a previous article on sleep and performance. For more information on pain management, check out this article.

It's also important to note that a longer nap isn't necessarily better. We sleep in cycles, and if you enter a deep sleep phase, you might struggle to get going again and perform well in the evening. So, keep the power nap short and effective: 10-30 minutes is an ideal range.