This is a post to complement Huffington's "sleep challenge." U.C. Berkeley reports this good news for afternoon nappers:

In the recent UC Berkeley sleep study, 39 healthy young adults were divided into two groups — nap and no-nap. At noon, all the participants were subjected to a rigorous learning task intended to tax the hippocampus, a region of the brain that helps store fact-based memories. Both groups performed at comparable levels.

At 2 p.m., the nap group took a 90-minute siesta while the no-nap group stayed awake. Later that day, at 6 p.m., participants performed a new round of learning exercises. Those who remained awake throughout the day became worse at learning. In contrast, those who napped did markedly better and actually improved in their capacity to learn. Matthew Walker, assistant psychology professor, has found that a nap clears the brain to absorb new information.

These findings reinforce the researchers' hypothesis that sleep is needed to clear the brain’s short-term memory storage and make room for new information . . .