A cup of strong coffee might make you feel wide awake, but a small study suggests that for improved physical and mental performance, an afternoon nap works better.
Scientists spent a morning training 61 people in motor, perceptual and verbal tasks: tapping a keyboard in a specific sequence, discriminating between shapes on a computer screen and memorizing a list of words. Then the scientists randomly divided the subjects into three groups. The first took a nap from 1 to 3 p.m. At 3, the second group took a 200-milligram caffeine pill, and the third took a placebo. The subjects repeated the tasks they had been taught earlier and were scored by researchers who did not know which group they were in.
Those who had caffeine had worse motor skills than those who napped or had a placebo. In the perceptual task, the nappers did significantly better than either the caffeine or placebo group. On the verbal test, nappers were best by a wide margin, and the caffeine consumers did no better than those given a placebo. Despite their mediocre performance, caffeine takers consistently reported less sleepiness than the others.
“People think they’re smarter on caffeine,” said Sara C. Mednick, an assistant professor of psychiatry at the University of California, San Diego, and the lead author of the study, which appeared in the Nov. 3 issue of Behavioral Brain Research. “But this study is a strong argument for taking a nap instead of having a cup of coffee.”