Around 8 to 10 hours of sitting a day. In big studies, that's the range where health risk tends to climb. "Sitting" here means awake time spent parked — desks, screens, car seats, couches.
It adds up faster than you'd think. A school or office day, the ride home, dinner, then a few shows. You can pass 8 hours without noticing.
On average, people who sit more tend to have more heart trouble and to die earlier.
One honest note: there's no magic line where 8 hours is safe and 10 is not. It's a slope, not a cliff. How much you move the rest of the day — and how often you stand up — matters too.
Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC6532816/
- https://www.psychiatrist.com/jcp/physical-exercise-and-health-5-sedentary-time-and-risk-of-adverse-outcomes/
- https://www.massgeneralbrigham.org/en/about/newsroom/articles/sedentary-time-cardiovascular-health
- https://www.sbm.org/healthy-living/move-more-and-sit-less-how-to-reduce-sedentary-time
- https://en.wikipedia.org/wiki/Sedentary_lifestyle
