You fall asleep within about half an hour and are usually awake and alert during the day. A morning warm-up period and a brief dip after lunch are normal. At night, waking up briefly several times is part of normal sleep, for example, while turning over, adjusting your pillow, or making a quick trip to the restroom. With increasing age, these waking phases become longer and more noticeable.
The average sleep requirement varies greatly among different people and age groups and is partly innate. For middle-aged adults, the recommended average sleep duration is between 7 and 9 hours. For adolescents, it’s between 8 and 10 hours (National Sleep Foundation, see table below). However, slightly more or slightly less is also considered “possibly adequate.” On individual nights, sleep duration can be shorter or longer.
The recommendation to sleep at least 8 hours every night is too general. Some people need less sleep and are still healthy and productive. Other people, however, need more than 8 hours of sleep. So, it’s about individual sleep requirements. Additionally, sleep is dynamic: if we sleep less one night, we usually sleep more the next night (or on the weekend). Our body can compensate very well for short-term reductions or disturbances in sleep. A problem only arises when sleep is disturbed over a longer period (e.g., for more than a month).
I can best determine my individual sleep needs if I can sleep without restrictions over a longer period. This works best during holidays without morning appointments. If my sleep on the weekend is longer than during the work or school week, this is a sign of insufficient sleep during the week. A good sign of sufficient sleep is feeling rested and being awake and productive throughout the day. However, someone who has intentionally slept little for a very long time (e.g., to be “more productive”) sometimes no longer realizes that their actual sleep need is greater. This can then lead to exhaustion in the medium term.