It’s often recommended that we get 7-8 hours of sleep and any less than that is not healthy. To find out what happens to your body when you sleep, researchers assigned three groups four, six and eight hours of sleep for fourteen days.
The group with eight hours of sleep had less attention lapses and cognitive issues whereas the groups that got four and six hours of sleep showed a decline. After two weeks, the group with six hours of sleep showed a similar reaction as someone with a blood-alcohol level of 0.1%, which is considered legally drunk. The group with four hours of sleep showed the same result or worse by falling asleep during their cognitive tests.
If you have gotten 4-5 hours of sleep for years and you feel fine, your brain is actually tricking you and you’re no longer aware of how much sleep you need.