A New Study Has Terrible News for Coffee Drinkers

June 23rd 2016

Alex Mierjeski

Coffee is hailed as the cure-all for the weary: a silver bullet for life-hacking your way out of crippling sleep deprivation.

But its powers might be more limited than you think — or want — according to a new study.

If you don't get enough sleep — five hours or more, according to researchers — for three nights in a row, that cup of coffee (or four) is probably worthless, according to findings presented at the SLEEP 2016 conference in Denver by the American Academy of Sleep Medicine and the Sleep Research Society.

"These results are important, because caffeine is a stimulant widely used to counteract performance decline following periods of restricted sleep," Tracy Jill Doty, a research scientist at Walter Reed Army Institute of Research, said in a statement. "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."

Researchers tracked 48 people for the study. After indulging in five days of 10-hour sleeps, study participants were subjected to five hours of sleep a night.

Afterward, researchers gave half the group two caffeine pills equivalent to a strong cup of coffee; the other half got placebos.

The first group reported improvement in the performance of tasks, but only for the first two days. After that, they became "more annoyed than those in the placebo group."

For the chronically sleep-deprived, then, it's probably best not to down cup after cup of coffee in search of revitalization. But if you do, at least you can be sure the coffee (probably) won't give you cancer.