There are some people who needs only 3 hours of sleep.other needs 10 hours of sleep.After the age of 50,the average sleep time goes down to 6.5 hours a night.We need less sleep as we get older.
Most people have some nights when they cannot sleep.About one in three Americans has a problem with sleep.Many of these people cannot fall asleep.The name of this problem is insomnia.The word insomnia means'no sleep'.Some people say,'I didn't sleep all night' but that's not really true.They may sleep lightly and wake up several times.Tn the morning,they only remember the times they were awake,so they think they were awake all night.