The nappuccino (caffeine + nap)

Drink a coffee immediately before a twenty-minute nap — the caffeine kicks in just as you wake up.

Why it works

Caffeine takes approximately twenty minutes to cross the blood-brain barrier and exert its adenosine-blocking effect. By drinking caffeine immediately before a nap, you capture the alertness benefit of the nap and have the caffeine clearing receptors at precisely the moment of waking, creating a compound alertness effect that outperforms either alone. The nap clears the adenosine load; the caffeine blocks the receptors from being re-occupied.

How to do it

1. Drink a caffeinated beverage (coffee or tea, 100–200mg caffeine) immediately before lying down.
2. Set an alarm for twenty minutes and nap normally — the caffeine is not yet active so sleep is not disrupted.
3. Wake with both the nap benefit and the caffeine onset arriving simultaneously.

Evidence

The caffeine-nap combination (nappuccino) outperformed caffeine alone, nap alone, and placebo on alertness and driving simulation performance in at least two controlled studies. (rct)

The nappuccino is most effective for acute sleepiness and driving-type performance; it is not a long-term sleep debt fix, and people with caffeine sensitivity should use a lower dose.

Sources

• Reyner & Horne (1997), suppression of sleepiness in drivers: combination of caffeine with a short nap, Psychophysiology

Common mistake

Drinking coffee, waiting twenty minutes for it to "kick in," then trying to nap — at which point the caffeine is already blocking adenosine and sleep is impaired. The caffeine must be consumed immediately before lying down.