Same. I've been told I'm a "high metabolizer". I can drink a cup of coffee/tea/soda before bed and pass out. No noticable effect.

It's weird that you mention the runner's high, too. I've run 6 miles 3x a week for months on end (PR of 8.5 miles), and I have no idea what other runners are talking about. I've never put the two together before.