Yes, sitting too long can kill you, even if you exercise - CNN | Professional Learning for Busy Educators | Scoop.it
From www.cnn.com - September 12, 2017 8:50 AM
Take a movement break every 30 minutes, say experts. No matter how much you exercise, sitting for excessively long periods of time is a risk factor for early death, a new study published Monday in Annals of Internal Medicine found.

There's a direct relationship between time spent sitting and your risk of early mortality of any cause, researchers said, based on a study of nearly 8,000 adults. As your total sitting time increases, so does your risk of an early death.