Teenagers (14 to 17 years): 8 to 10 hours of sleep. Young adults (18 to 25 years): 7 to 9 hours of sleep. Adults (26 to 64 years): 7 to 9 hours of sleep. Older adults (65 years or older): 7 to 8 hours of sleep. Although most men and women need about seven to eight hours of sleep per night, their sleep patterns are generally different.