More than half of the average person’s waking hours are spent sitting: watching television, working at a computer, commuting, or doing other physically inactive pursuits. But all that sitting could be sending some to an early grave. That’s the conclusion of a Canadian study published in this week’s Annals of Internal Medicine. People in the study who sat for prolonged periods of time had a higher risk of dying from all causes — even those who exercised regularly. The negative effects were even more pronounced in people who did little or no exercise. In addition to premature death, the study documented higher rates of type 2 diabetes, cancer, and cancer-related deaths in very sedentary people. If you sit for work, try standing or moving around for one to three minutes every half hour. Better yet, think about working at a standing desk. At home, stand when watching TV or talking on the phone.