What you're doing, right now, at this very moment, is killing you. More than cars or the Internet or even that little mobile device we keep talking about, the technology you're using the most almost every day is this, your tush. Nowadays people are sitting 9.3 hours a day, which is more than we're sleeping, at 7.7 hours. Sitting is so incredibly prevalent, we don't even question how much we're doing it, and because everyone else is doing it, it doesn't even occur to us that it's not okay. In that way, sitting has become the smoking of our generation.