Written By: James Hewitt
Can’t stop yawning?
Feeling sleepy in the afternoon is a common experience. Sometimes, we put this down to overeating at lunch, but the ‘post-lunch dip’ is driven by our body clock. Find out what you can start doing to counter this.
The history of afternoon sleep spans thousands of years. Wealthy Romans took a two-hour break at the sixth hour of daylight, the sexta, which fell between 1:00 pm to 3:00 pm depending on the time of year. This Latin word is the basis for the Spanish siesta. In modern times, taking a nap can feel like a decadent luxury. However, even renowned workaholics, such as Winston Churchill, swore by the powers of a 20-minute nap to restore their energy, even though he regretted having to “send himself to bed like a child every afternoon.”
Our Tendency to Sleep Follows a Predictable Pattern
Perhaps Winston shouldn’t have been so hard on himself. Even when we are well-rested, our tendency to fall asleep follows a biphasic pattern. People generally fall asleep most quickly and easily between 5:30 am – 07:30 am, and around 3:30 pm, which contributes to our feeling sleepy in the afternoon. Studies have also demonstrated that the post-lunch dip occurs whether we have eaten or not.
Can Taking a Nap Make You Feel Sleepier?
While it’s natural to crave a short sleep in the afternoon, surrendering to this urge can make us feel even sleepier when we wake up. This experience is related to sleep inertia, which describes how our cognitive performance and physical coordination are worse immediately after waking. Thankfully, several studies have investigated how we can maximize the benefits while minimizing post-nap sleepiness.
Combining 200mg of caffeine (equivalent to a large, strong Americano coffee), with a 20-minute nap, can reduce sleep inertia and improve performance. The ‘Nappuccino’ (as it is sometimes called) is effective because caffeine takes about 15-20 minutes to reach peak levels in our blood. This characteristic means that the caffeine doesn’t stop you from getting to sleep, but it will begin to kick in towards the end of the nap, helping you wake up and feel more alert.
The Downside of Combining Caffeine and Naps
However, it’s not that easy. The problem with combining caffeine and a nap is that the same properties that keep us awake in the day stop us from sleeping at night. Even if you stop drinking anything caffeinated 6 hours before you go to bed, it could reduce total sleep time by more than one hour. As a simple rule of thumb, avoid caffeine after midday (except for in emergencies).
Fortunately, using caffeine isn’t the only way to wake yourself up after a nap. Studies also demonstrate that exposing yourself to bright light immediately following a nap was almost as effective as using caffeine. Just 2,000 Lux of light exposure, equivalent to going outside, even on a cloudy day, was sufficient.
Whether you choose to use caffeine or not, keep naps under 20 minutes, and don’t nap after 3:00 pm. But, if you’re feeling sleepy after lunch, a short nap may be just what you need to boost your alertness and performance for the rest of the day.
James Hewitt is a performance scientist and award-winning communicator. He has dedicated his career to enabling people to perform at their best through sharing novel data, cutting-edge insights, and practical tools, developed in his work with the world’s most demanding & top-performing organizations.
- Churchill WS. War. In: The Gathering Storm. 1st ed. New York, NY: Houghton Miffin Company; 1948. p. 375.
- Carskadon MA, Dement WC. Multiple Sleep Latency Tests During the Constant Routine. Sleep. 1992;15(5):396–9.
- Hayashi M, Masuda A, Hori T. The alerting effects of caffeine, bright light and face washing after a short daytime nap. Clin Neurophysiol. 2003;114(12):2268–78.
- Reyner LA, Horne JA. Suppression of sleepiness in drivers: Combination of caffeine with a short nap. Psychophysiology. 1997;34:721–5.
- O’callaghan F, Muurlink O, Reid N. Effects of caffeine on sleep quality and daytime functioning. Risk Manag Healthc Policy. 2018;11:263–71.