Sitting for more than three hours a day can cut two years off a person's life expectancy.

The story behind the answer

True—large epidemiological studies link prolonged sitting to higher risks of heart disease, type 2 diabetes, some cancers, and early death. A 2012 BMJ Open analysis estimated that if Americans limited sitting to under three hours per day, population life expectancy could rise by about two years, highlighting the sizable impact of sedentary time.

Why it matters: Sitting keeps major muscles inactive, blunting calorie burn, worsening insulin sensitivity and blood lipids, and reducing vascular function—even if you exercise later. The good news: breaking up sitting with short bouts of light movement (standing, walking, stretching) every 30 minutes improves glucose and lipid handling. Memory tip: “3-2-30”—more than 3 hours sitting is linked to up to 2 years lost; stand or stroll every 30 minutes.