The Science of Caffeine Naps

Think a cup of coffee and a nap are opposites? Science suggests combining them might be the ultimate

energy hack. It is all about the timing. Research shows that consuming caffeine

immediately before a short, 20-minute nap is especially effective at reducing "post-nap

fog," or what scientists call sleep inertia. Because caffeine typically takes about 30 to 120

minutes to reach peak levels in your blood, it doesn’t interfere with the nap itself.

Instead, as you wake up, the caffeine begins to block the receptors for adenosine—a

substance that builds up in your brain to signal sleepiness. This "caffeine-nap" combo has been shown

to improve working memory and alertness much better than just a nap or just a cup of coffee