If you want to find a real medical controversy, try talking to sleep experts. It seems that there is little agreement on any major issue.

This is a completely different way of looking at sleep. Learn from the lions.

New York Times

…“Why should lions get 15 hours a night and giraffes just 5 — when it is the giraffes who will be running for their lives come hunting time? How on earth do migrating birds, in flight for days on end, sleep? Why is it that some people are early birds as young adults and night owls when they’re older?

“The answer may boil down to time management, according to a new paper in the August issue of the journal Nature Reviews Neuroscience. In the paper, Jerome Siegel, a professor of psychiatry at the University of California, Los Angeles, argues that sleep evolved to optimize animals’ use of time, keeping them safe and hidden when the hunting, fishing or scavenging was scarce and perhaps risky. In that view, differences in sleep quality, up to and including periods of insomnia, need not be seen as problems but as adaptations to the demands of the environment. (Emphasis added)

“We spend a third of our life sleeping, and it seems so maladaptive — ‘the biggest mistake nature has made,’ scientists often call it,” said Dr. Siegel, who is also chief of neurobiology at the V.A. Greater Los Angeles Healthcare system. “But another way of looking at it is this: unnecessary wakefulness is a bigger mistake.”

Source: New York Times, August 31, 2009

Citation: Nature Reviews Neuroscience, August, 2009