WASHINGTON: Healthy older adults need less sleep than their younger counterparts and, even with less sleep under their nightcaps, are less likely to feel tired during the day, a study published Monday showed. The time spent actually sleeping out of eight hours in bed declined progressively and significantly with age, the study published in SLEEP, the official journal of the American Academy of Sleep Medicine and the Sleep Research Society, said. Older adults, aged 66-83, slept about 20 minutes less than middle-aged adults (40-55 years), who slept 23 minutes less than young adults aged 20-30, the study said. The older adults woke up significantly more often and spent more time awake after initial sleep onset than younger adults. Deep, or slow-wave sleep, thought to be the most restorative phase of sleep, decreased with age, the study said. But although older adults slept less deeply and less overall, and their sleep was less continuous than their younger counterparts', the