For many years I had insomnia. I was in a VERY busy job which was on the go all the while; I would either not go to sleep or would wake after a few hours - one night I thought 'Oh I'm awake again, but I didn't die last time' and didn't have problems after that.
In more recent years if I get a night when I am awake I read; listen to the radio; make a cuppa; doze. I believe that sleep should be taken when the brain requires it. 'experts' say to keep to a strict routine but I have never agreed with that. Babies sleep when they grow or when they are tired.
Humans are now kept to a strong regime of having to wake by the alarm clock, probably before we are 'ready' to wake - in order to keep our jobs, get the kids to school etc.. Instead of being able to have an afternoon kip if necessary we have to keep 'going'

……. so our brains are often fighting sleep which impacts on the rest of Life.