Daily life has its satisfactions: The perfect reply to a friend's text message; The first after-work drink; The sound of another government U-turn. But do any really compare to the joy of going to sleep? That moment when the mess of 21st-century existence disappears into the non-judgmental hug of a bed?
Somehow we have pushed this pleasure to the back of the queue. A third of American adults report sleeping less than the recommended seven hours. Many of us feel under-rested. For some, the problem is modern life; emails, to-do lists and screens. For other people, it's the demands of work or family. Then there are those who can't sleep when they try. In 1895 the Earl of Rosebery resigned after barely a year as British prime minister, unable to overcome his insomnia（失眼眠症）. Up to 1 in 10 adults meet the criteria for insomnia.
Stressing ourselves out about a lack of sleep can make the problem worse. In his book Overcoming Insomnia and Sleep Problems, Oxford professor Colin Espie writes about "orthosomnia", where people are so focused with sleeping well that they become too anxious to do so. The marketing of sleeping aids adds to this.
Espie says we each have a sleep pattern that, like a shoe size, we figure out through trial and error. Genetically, some humans are larks（百灵鸟） and some are owls; the larks may just have better cardiovascular（心血管的）health. For an owl to try to fight their natural schedule, and sleep earlier, wouldn't necessarily help.
Once we weren't urged to sleep until we were dead. Now we are told to sleep or we'll be dead. Nowadays sleep is becoming something that people hope to excel at. About that I'm unconvinced. A good night's sleep is a great pleasure. As far as possible, it should also remain a simple one.
