Tired all day after oversleeping? Here's why.

You most certainly happened to oversleep one time but, after you woke up, you inexplicably felt more tired than usual and couldn't figure out why.

Michael Breus, a psychologist with the American Academy of Sleep Medicine, explains that our body gets used to a certain sleep schedule and any irregularity brought to it is felt by our bodies and disrupt our balance.

This is the reason why it's recommended to go to bed and wake up approximately at the same hours every day.

A few extra hours of sleep will not revigorate your body, as you might expect but, on the contrary, they will interfere negatively with how your organism manages the energy it receives through sleep.

The average length of a sleep cycle is around 90 minutes. Each person normally passes through 5 complete cycles during one night's sleep. That makes a total of 7.5 hours of slumber.

Such is the case that if you wake up an hour later, after you've slept for 8.5 hours, that means you'll wake during last stages of the sleep cycle, when your sleep is the most profound.

That is the reason you may find it so hard to wake up and get out of bed and also the reason why you will feel tired and dizzy all day.

Michael Breus also draws attention that, as far as sleep is concerned, quality is more important than quantity, pointing to the people who, although sleep many hours each night, constantly feel tired.