A better way would be to monitor when you are active in gmail. I bet that a pattern would emerge. If you're a nightbird your gmail activity would reveal this. I

A better way would be to monitor when you are active in gmail. I bet that a pattern would emerge. If you're a nightbird your gmail activity would reveal this. If you go swimming every wednesday from 9 to 11 it would also show up. Combined with timezones and some statistics this could give a much more accurate picture, not only of when you're awake but when you're actually at your inbox.