sitting disease
n. Weight gain, heart disease, and other health problems caused by excessive or prolonged sitting.
Examples
2014
Prolonged sitting, it turns out, flips biochemical switches inside muscle cells that boost your odds for heart failure, up your risk for fatal heart disease by 27 percent and fatal cancers by 21 percent, even if you exercise regularly. …

Fortunately, the way to cure sitting disease is simple: Wake up your muscles (especially the big ones in your legs, butt and core) with just two minutes of movement every 30 minutes!
—Dr. Michael Roizen & Dr. Mehmet Oz, “You Docs: Stand up to ‘sitting disease’ at home and work,” The Roanoke Times, February 25, 2014
2013
In a 13-year study that analyzed the lifestyles of more than 17,000 men and women, scientists at the Pennington Biomedical Research Center in Louisiana found that people who sit most of the day are 54 percent more likely to die of a heart attack.

And get this: The so-called "sitting disease" affects smokers, nonsmokers, dedicated exercisers and healthy eaters. This is just one of many studies to crop up in recent years with similar evidence.
—Lauren Ennis, “New year, new you: 13 healthy habits to adopt in '13,” Fort Worth Star-Telegram, January 03, 2013
2009 (earliest)
Many overweight people in the USA have "sitting disease" and would lose weight if they did more walking, standing and moving around during the day, says endocrinologist James Levine of the Mayo Clinic in Rochester, Minn.
—Nanci Hellmich, “Q&A: How to drop pounds with all-day activities, not exercise,” USA Today, January 22, 2009