Wednesday, April 28, 2010
How to nap
Even naps as short as ten minutes have been shown to provide psychological benefits in terms of reduced fatigue and improved concentration (pdf). But would-be nappers face some strategic decisions, most obviously - does it matter whether I nap in my chair or ought I try to find somewhere to lie down? And then ... if remaining seated, is it okay to lean forwards and rest my head on a desk?
When it comes to napping while leaning back in a chair or car seat, past research has shown that the further you can lean back, the better, at least in terms of subjective fatigue and reaction times. Now Dayong Zhao and colleagues have addressed the leaning forward issue, comparing lying-down napping and leaning-forward napping, and they've found that the former is the most effective, but that the leaning-forward variety still has clear benefits compared with no nap at all.
Thirty undergrads, all regular nappers, had electrodes attached to their heads before lunch. Then they performed an 'oddball' auditory task in which they had to listen to a string of tones and listen out for the occasional one of a different pitch. Next they had lunch before splitting into three groups: one group enjoyed a twenty minute nap lying down; another enjoyed a twenty-minute nap leaning forwards onto a desk (plus pillow for comfort); the final group just spent the same time sitting quietly.
After this, all the participants performed a repeat of the oddball task whilst having their brainwaves recorded via electroencephalography. Zhao's team were particularly interested in the size and delay of the P300 - a brainwave measure of cognitive alertness.
Participants in both of the napping conditions showed benefits compared with their peers who'd been denied a nap. The nappers, leaning and lying, reported being in a better mood and feeling less sleepy and they performed better at the oddball task. When it came to the brainwave recordings, however, the leaning-forward nappers, unlike the lying-down nappers, showed no difference from the control group. Uniquely, the lying-down nappers showed an increased P300 amplitude, perhaps indicating increased cortical arousal on their part.
The message it seems is clear. A post-luncheon nap is beneficial to your mental functioning even if you're forced to rest your head on your desk. However, if you can find somewhere to lie down properly, then do, because the benefits of the nap will be that much greater.