RESEARCH · 2003
The best way to wake up from an afternoon nap
Hayashi M, Masuda A, Hori T. The alerting effects of caffeine, bright light and face washing after a short daytime nap. Clinical Neurophysiology. 2003;114(12):2268–2278.
At a glance
- Who
- 10 young healthy adults
- Setup
- A nap at 12:40, with 15 minutes of computer tasks before it and an hour of tasks after
- Compared
- A 20-minute nap alone; 200 mg of caffeine then the nap; the nap then 1 minute of bright light; the nap then washing the face; and no nap
- Finding
- Caffeine before the nap worked best for both sleepiness and performance, for the whole hour after.
What they did
A team in Hiroshima looked at the post-lunch slump and asked what makes a short nap work better. Each volunteer went through five conditions: a 20-minute nap on its own, 200 mg of caffeine followed by the nap, the nap followed by one minute of bright light (2000 lux), the nap followed by washing their face, and resting without sleep. They did computer tasks for 15 minutes before the nap and for an hour after it, and rated how sleepy they felt.
What they found
- Caffeine plus the nap was the most effective for both how sleepy people felt and how well they performed, and the effect lasted the whole hour.
- Bright light after the nap was about as good for sleepiness, but not for performance.
- Washing the face helped right after waking, but the effect was mild and short-lived.
What it means for your coffee nap
Have the coffee before the nap, not after. And when the alarm goes, getting some daylight or splashing water on your face gives you an extra push in the first few minutes, which is why our how-to ends with that step.
Limits
Ten people in a lab, napping at one fixed time of day. Results in everyday life will vary.