Eli5: Why does it take a while to ‘start up’ after you wake up and how does that happen?



Why is it that we are so slow in like the first minute we wake up compared to lets say an hour later when we feel fully ‘awake’? Why do I feel more awake after splashing water on my face for example?

In: Biology

It’s called sleep inertia. Basically your body takes a while to wake up and it needs time to fully start processing everything around you and move your body. Your body does this thing where it likes to sleep during the typical night and awake during the typical day. If you disrupt that cycle,or the circadian rhythm, you’ll be subjected to sleep inertia. Think of night shift workers, or if you stay up too late how horrid you feel when you wake up. Healthline says sleep inertia can also be caused by blood not getting to the brain fast enough. But that’s just one reason. You can look it up, there’s plenty on it out there.