A recent Cornell University study of 93,000 women over 50 found that those who sit 11 or more hours per day tended to die earlier than those who have under five hours of inactivity daily. An earlier study suggests that just a few hours in front of the computer or TV each day doubles your risk of heart trouble. Scarier still, regular exercise doesn’t counteract the effect. The good news is that there are tons of ways to sneak physical activity into your day, even if you have a desk job. The easiest might be the most effective: Get up! Visit a co-worker rather than emailing, do some midday stretches, or just take a stroll around the office.