The Deadly Effects of Sitting for Over 6 Hours a Day Whether it be at work or in front of the TV, sitting for longer than six hours is considered prolonged sedentary behavior. It is projected to put 1.4 billion people worldwide at risk for chronic diseases. A study at Queens University Belfast found that prolonged sedentary behavior was the cause of a number of issues in the U.K. It was responsible for 16.9% of type two diabetes cases and 4.9% of cardiovascular disease cases. It also may be behind 7.5% of lung cancers, 9% of colon cancers and 8% of endometrial cancers. Attempts to treat patients with these conditions cost the U.K. an estimated £762 million between 2016 and 2017. Sedentary behavior was also associated with over 69,000 deaths in the U.K. in 2016. Incorporating small amounts of movement into the day, such as a lunchtime walk, can reduce the risks. Walking, dancing or gardening for as little as 10 minutes a day is associated with an 18% reduced risk of death.