Christoph Niemann

THE FACTS

Late November is the start of the busiest travel season of the year, when millions of drivers hit the road for long-distance treks. Many will be sleep-deprived and looking to pull over for a nap or a dose of caffeine.

But the best idea may be to combine the two, and not in the order one might think.

Ordinarily, sleep experts advise steering clear of coffee and other stimulants before resting, since caffeine disrupts sleep. As a result, studies on drowsy drivers have generally compared the restorative benefits of pulling over and napping versus pulling over for a cup of caffeine. Researchers have found that a 15- to 30-minute nap increases alertness and driving performance, but most studies show that drinking caffeine is a slightly superior strategy.

In a series of studies, however, sleep researchers in England found that drinking a cup of coffee and then immediately taking a 15-minute nap was even more effective. The researchers tested sleep-deprived subjects in driving simulators and found that a “caffeine nap” improved driving performance and reduced sleepiness better than other commonly employed techniques, including cold air, a short nap, a break with no nap or 200 milligrams of caffeine, roughly the amount in a 10-ounce cup of strong brewed coffee.

This method is believed to work because the short power nap helps clear the brain of the sleep-inducing compound adenosine. Caffeine, meanwhile, takes about 20 minutes to have its physiological effect — kicking in just as the napper is awakening.

THE BOTTOM LINE

A cup of coffee followed by a 15-minute nap may be more restorative than either one alone.