After Three Bad Nights of Sleep, Coffee Can't Do Anything for You

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As a rule, we Americans don’t get enough sleep. In fact, one in three of us are consistently stinting ourselves on the seven or more hours our bodies need each night, according to a recent Centers for Disease Control and Prevention study. We know who we are (though we may be too tired and cranky to admit it).

So how are we getting through the day, not to mention the five-day workweek? One word: caffeine.

Unfortunately, that cup of coffee or tea (or soda or whatever form of caffeine you generally enjoy) will get you only so far.

Yes, we have bad news, caffeine addicts. According to a new study released by the American Academy of Sleep and presented on June 13 and 14 at Sleep 2016, the annual meeting of the Associated Professional Sleep Societies LLC, after you sustain three nights of the less-than-optimal amount of five hours of sleep, caffeine has almost no benefit at all, improving neither your alertness or performance. At that point, you’re basically in a zone where espresso cannot help you. I know, terrifying.

Researchers found that, when restricting the sleep of 48 study participants to five hours per night for five days, 200 milligrams of caffeine twice a day (each dose about the equivalent of a cup of coffee) “significantly improved” the participants’ performance on tasks, relative to the effects of taking a placebo, for the first two days of the study. But on the third day of sleep restriction (basically, the study’s equivalent of your usual Wednesday), the two caffeine doses had no measurable effect.

“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’s lead author, Tracy Jill Doty, Ph.D., a research scientist at Walter Reed Army Institute of Research, said in a release.

Doty noted that she and her fellow researchers were “particularly surprised” that caffeine lost its performance-boosting power after only three nights of limited sleep.

It’s probably safe to say they aren’t the only ones.

Photo courtesy of iStock