Picture of a woman who woke up tired because she was sleeping too many hours.

Why does too much sleep make you tired?

“More” and “better” have always been a deceptive alliance. The richer, the happier; the older the wiser; a lot of coffee, a lot more energy. It seems logical to apply this dogma to the activity we engage in almost a third of our life – sleep.

So let’s explore why does too much sleep make you tired?

However, personal experience seems to contradict this. Even the most convinced late riser will have to admit sooner or later that this plan will not work. At some point you no longer wake up feeling refreshed, but weak and without energy. But why do you get tired if you sleep too much?

Stages of sleep

A first approximation to the correct answer could be: We all follow a certain rhythm – even while sleeping. Sleep is not a monotonous falling out of the world, but is divided into a few phases:

  • light sleep phases
  • deep sleep phases
  • REM phases

These follow each other within 90-100 minutes, with the cycle starting several times a night. Their ratio changes over the course of the night. The comparatively superficial light sleep phases, in which we let ourselves be disturbed more quickly by external influences, increase. The deep sleep phases dominating at the beginning of the night, in which the body recovers most efficiently, become shorter. To do this, we fall more and more into REM sleep towards the end of the night. REM is the phase in which the brain uses about as much energy as it does when awake, despite sleep. In the REM phase, we process emotions and dreams. What exactly happens during this time is still not entirely clear to researchers.

The sleep-wake cycle

We also follow rhythms during the day – this can be seen, for example, from the fact that a certain amount of tiredness sets in every 90 minutes. If we give in to this, for example to take an afternoon nap, there is a risk of falling into a deep sleep phase. If we wake up in a light sleep phase, for example after a power nap, it is easy for us to get up. However, if we wake up during deep sleep, we feel drowsy.

The genetic predisposition of an average person is to sleep seven and a half to eight hours of sleep a day, with short and long sleepers. The latter can sleep nine to ten hours. But how do you find out what type of sleeper you are? We recognize our own need for sleep in times when we are not subject to the alarm clock, appointments or excessive stress and can wake up naturally – after a few days, the amount of sleep then settles down to the personal optimum.

Why do I sleep so much and still feel tired?

If we sleep longer than necessary, this will upset our sleep-wake cycle. We can hardly reach the relaxing deep sleep phases and the stress hormone cortisol, which rises from around five in the morning, keeps our bodies busy. The brightness of the day and body temperature, which increases after a sufficient amount of sleep, additionally dampen sleeping comfort. Non-restorative sleep does not satisfy the need for more sleep. To make matters worse, too much sleep can lead to pernicious cycles.

However, the cause of an excessive need to sleep is not always a previous lack of sleep. It can also be the expression of a chronic illness, such as depression, or it can be caused by medication or eating habits. Nicotine, alcohol and coffee do not go well with restful sleep.

In short: we get tired if we wake up in the wrong phases of sleep or our quality of sleep is poor. Oversleeping provokes both.


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Feel free to share your knowledge and ideas about being tired after oversleeping.







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