Sleep-deprived for several days? Don’t count on caffeine to stay alert, study says

Silver Spring, MD – Caffeine found in coffee, tea and soft drinks doesn’t appear to be enough to ward off the negative effects of getting too little sleep over several consecutive nights, according to a study from the Walter Reed Army Institute of Research.

For the study, researchers restricted the sleep of 48 adults to five hours for five consecutive nights. Two times a day, participants were given either 200 milligrams of caffeine or a placebo.

Participants also underwent a psychomotor vigilance task, which measures how long it takes to respond to a visual stimulus. Caffeine boosted performance for the first two days but not the final three, researchers said.

“We were particularly surprised that the performance advantage conferred by two daily 200 mg doses of caffeine was lost after three nights of sleep restriction,” Tracy Jill Doty, research scientist, said in a press release “These results are important, because caffeine is a stimulant widely used to counteract performance decline following periods of restricted sleep. The data from this study suggests that the same effective daily dose of caffeine is not sufficient to prevent performance decline over multiple days of restricted sleep.”

The study was presented at the 30th annual meeting of the Associated Professional Sleep Societies in June.

The Centers for Disease Control and Prevention recommends adults sleep seven to eight hours every night.