looks like only 15% of american adults are awake at 4 am. ppl like to sleep in! http://flowingdata.com/2015/12/15/a-day-in-the-life-of-ameri...
From the article: By waking up at 4 a.m., they’ve essentially wiped a lot of those distractions off their plate. No one is expecting you to email or answer the phone at 4 a.m.