An 85-year-old is better off sleeping 5 to 8 hours a day, with specific times to be determined by individual work habits, etc. There is no consistent answer.
Adequate sleep is very important for health. It is a necessary physiological process in which body organs are repaired during sleep. However, it is not the longer the better to sleep, too long or too short sleep is not conducive to health.
Generally speaking, the recommended sleeping time for adults is 8 to 9 hours. Elderly people older than 65 years old will shorten the sleep time, but it is also recommended to reach 5 to 8 hours, not less than 5 hours, the specific time or according to the actual situation of each person.
From a scientific point of view, there is no strict time requirements for sleep, rather than care about the length of sleep, should pay more attention to the regular work and rest time and good sleep quality. If the work and rest time is not regular, wake up feeling tired, are not good sleep.
Therefore, it is best to ensure that 85-year-old people have 5 to 8 hours of sleep, and it is more important to maintain a regular routine and good quality of sleep in order to help improve health.