Sedentary behaviour

Sedentary behaviour means time spent sitting or lying down while awake and using little energy: desk work, driving, screens on the sofa. Exercise and sitting are separate things. You can run every morning and still sit for ten hours a day. The best evidence says that a lot of physical activity can offset the health risk of long sitting, but most people do far less than that, and for the back the length of each sitting bout matters in its own right. This page covers what the research shows and what to do with it.

Does exercise cancel out sitting?

Mostly, if you do a lot of it. A 2016 meta-analysis in The Lancet pooled 16 studies with more than 1 million adults followed for up to 18 years.¹

Finding	Detail
Least active people who sat 8+ hours a day	About 59% higher mortality than the most active people who sat under 4 hours
Most active quarter	No increase in mortality with long sitting time
How much activity that took	About 60 to 75 minutes of moderate activity a day
TV time of 3+ hours a day	Higher mortality at all but the highest activity level, where risk rose only at 5+ hours

Two practical readings follow. First, an hour of brisk walking a day is a lot more than most people do, so for most of us sitting less still matters. Second, any step up in activity helps: risk fell across each level of activity, not only at the top.¹ See how many steps you actually need.

What about your back?

The back is a different question from mortality. Reviews that compare people at one point in time find that people who sit more report more back pain,² but reviews that follow people over time do not find that sitting time causes new back pain.³ Part of the link runs the other way: people in pain sit more. What does hold up is that long uninterrupted sitting makes existing pain more disabling. The detail is in does sitting cause back pain?

That is why the bout matters more than the daily total. In an office trial, alternating sitting and standing every 30 minutes cut lower back discomfort by about a third and reduced fatigue.⁴ See how often to take sitting breaks.

Sitting less versus moving more

Goal	What helps	Evidence
Offset the health risk of sitting	About an hour of moderate activity a day; any increase helps	Large cohort meta-analysis1
Less total sitting at work	Sit-stand desks: 84 to 116 minutes less sitting a day in the short term	Very low quality evidence, Cochrane review5
Less back discomfort during the day	Break each sitting bout every 20 to 30 minutes	Randomised crossover trial4
Fewer back pain recurrences	A progressive walking programme	See walking for back pain

They are not alternatives. Daily activity protects long term health; breaks protect your back and comfort through the day.

A realistic plan

1. Walk most days, and build up over time. In the meta-analysis, about an hour of moderate activity a day removed the extra risk of long sitting; less still helped.
2. Break the bouts. Stand or move every 20 to 30 minutes at work, and during long evenings on the sofa.
3. Cut the longest stretches first. Long drives, long meetings, long screen sessions at night.
4. Use the setup. A standing desk makes switching easy, if you actually switch.
5. Count the whole day. Office and evening sitting add up; see office and desk workers.

Footnotes

1. Does physical activity attenuate, or even eliminate, the detrimental association of sitting time with mortality? A harmonised meta-analysis of data from more than 1 million men and women. 2016. ↩ ↩² ↩³

2. Association between sedentary behavior and low back pain: a systematic review and meta-analysis. 2022. ↩

3. The association between sedentary behavior and low back pain in adults: a systematic review and meta-analysis of longitudinal studies. 2022. ↩

4. Breaking up workplace sitting time with intermittent standing bouts improves fatigue and musculoskeletal discomfort. 2014. ↩ ↩²

5. Workplace interventions for reducing sitting at work (Cochrane review). 2018. ↩