Coffee doze

News that a cafe in Tokyo was offering snooze space to customers prompted, for us, a timely reminder about the benefits of coffee naps.

In the case of Nescafe Harajuku, with the purchase of at least one food item, customers were eligible to score a two-hour siesta on one of 10 customized beds designed to recline at any angle, complete with adjustable lighting and music to aid slumber [pictured below]. A complimentary decaf was served prior to. [See: Tokyo's new nap cafe is an actual dream come true]

As lovely as this sounds, Tokyo's Nescafe Harajuku wasn't maximizing the real buck-up potential of a hit of actual caffeine followed by a brief doze.

As it turns out, coffee naps are a thing and they can help to reinvigorate us more than just a coffee or a nap by itself, but the length of the wind down is everything. [See: Scientists agree: Coffee naps are better than coffee or naps alone]

Various studies show that consuming caffeine without dawdling - perhaps an espresso or iced-coffee - before settling in for a nap - timed to last no more than 20 minutes - can provide a significant energy boost.

The reason is, however, snooze-inducing sciencey.

Sleep is regulated by adenosine molecules in our brains. When these molecules bind to their specific receptors in the neural membrane, our brain wave activity slows down and we feel tired. Some substances can imitate these natural neurotransmitters like adenosine and help themselves to their receptors, which can't tell the difference. Caffeine is one such trickster.                                                 

The effect of caffeine on an awake subject is to steal some of the brain spots that belong to adenosine, blocking it from doing its job and curbing some of the drowsiness it would otherwise produce.

But just as the adenosine build-up which regulates sleep dissipates during rest, adenosine declines in our coffee nap also. With less adenosine to compete with in the battle over receptors, caffeine consumed prior to a 20-minute nap thus produces a greater effect. Our neural activity instead of slowing down, speeds up.

And there's another reason for that boost. A short nap is perfectly timed to benefit from a caffeine energy surge, which typically kicks in around 30 minutes after drinking.

Just be careful not to mistime your coffee nap. Wait too long after finishing your coffee and the caffeine will hit beforehand, leading to sleep disruption and poorer performance on waking.

Coffee naps won't resolve a sleep deficit either. But as a way to improve a power nap, they will leave you feeling full of beans.