I suffer from the unhealthy habit of worrying about my health. I try to eat well, supplementing with vitamins. I exercise. I floss. I use sunscreen before stepping out to check the mail. I avoid talking on my cell phone. For a few months in the late ‘90s, I worried about the health effects of electromagnetic fields. So a year or so ago, when studies began circulating about the harms associated with prolonged sitting, I had to take action. Or if not “action,” per se, the situation at least required some research.