Rsing at 4:00am is more likely to either be the symptom of someone addicted to their work above all else but it also probably shows the fragility of life at the top! If you were Tim Cook, what would you do next in a company with billions of spare cash to keep the investors away from your door and without losing focus?
Could also just be a circadian rythm thing. I’m sure there are many otherwise normal people who’s biological clock would prefer to sleep early and wake up at 4.
I don't think I would sleep if that was me!