Sean Drummond, a psychiatrist （心理医生） at the University of California, San Diego, said that older people are more likely to suffer from broken sleep, while younger people are better at sleeping   49   straight through the night.

    More sleep in old age, however, is   50   with better health, and most older people would feel better and more   51   if they slept for longer periods, he said.

    “The ability to sleep in one chunk （整块时间） overnight goes down as we age but the amount of sleep we need to   52   well does not change,” Dr Drummond told the American Association for the Advancement of Science conference in San Diego.

    “It’s   53   a myth that older people need less sleep. The more healthy an older adult is, the more t