Sedentary Behaviour

Prolonged waking time spent sitting or lying at very low energy expenditure. The paged evidence supports three claims in descending order of strength: sitting a lot is harmful; standing instead is barely better; moving — even a little — is what offsets it.

How harmful is sitting?

• A 2012 review: the most sedentary were more than twice as likely as the least to have or develop diabetes, with much higher premature-death risk.
• A 2015 review: harm "regardless of physical activity" — though the 2024 Taiwan cohort below qualifies this.
• "Sitting is the new smoking" is wrong by an order of magnitude: American Journal of Public Health 2018 put sitting's risk at about a tenth of smoking's.

Standing is not the fix

• Energy: +9 kcal/hour over sitting (2018 analysis).
• Cardiometabolic: 2020 pooled review, 9 trials, 877 people, +1.3 h standing/day for ~4 months — slight improvements in body fat and glucose control; no change in blood pressure, insulin, cholesterol, triglycerides.
• Harm: International Journal of Epidemiology 2024, 83,013 British adults, ~7 years — standing > 2 h/day raised varicose-vein and venous-ulcer risk.

Movement is

• 2024 cohort of ~482,000 Taiwanese adults: 15–30 minutes of extra daily exercise removed most of the excess mortality of a sitting job.
• "Active seating" (unstable/inflatable seats): heart rate +6–13% and energy +19–40% vs a normal chair (n = 20, Ergonomics 2019); over six months, an unstable seat pad cut new neck pain by 81% and lower-back pain by 84% among 133 Bangkok office workers (SJWEH 2024). Small or brief studies; seat-design dependent.

The practical restatement: the relevant contrast is still vs moving, not sitting vs standing. This connects directly to the front-loaded dose curve in Minimum Effective Dose of Exercise — a small movement dose buys most of the offset.

Open questions

• Whether standing's unmeasured channels (postural-muscle activation, blood flow) carry benefit the trials missed.
• Whether active-seating effects hold beyond six months and outside the specific seat designs tested.
• All harm estimates are observational associations.

Related

• Minimum Effective Dose of Exercise · Step Count Targets — the usual prescriptions for breaking up sitting.
• Type 2 Diabetes Remission — the 2× diabetes association for the most sedentary is upstream of the remission trials.
• Exergaming — a movement on-ramp for people who sit to game.