"Parents of teenagers say they have to shake them, or even turn the mattress over to wake them up, as if they were trying to wake the dead," said Professor Isabelle Arnulf, head of the sleep disorders ...

Stoddart’s advice rests on a basic but counterintuitive truth about sleep. “Unlike almost every other area of life, effort is not rewarded,” she writes. “The more you try, the less you are likely to ...