Habits that add years

Does sitting all day shorten your life?

By GyroscopeUpdated November 14, 20262 sources

Mostly through the moving you don’t do. In a study of over a million adults, people who sat more than 8 hours a day but also got about an hour of brisk activity had no clear extra risk. Break up long sits, and find that hour.

Why “sitting is the new smoking” took off

It’s a great line, and it fits how a desk job feels. Office workers sit for most of the day, and the idea that the chair itself is slowly harming you makes intuitive sense. But when researchers separated sitting from moving, most of the harm turned out to come from not moving.

The million-person study

In 2016, researchers pooled 13 studies covering 1,005,791 adults followed for 2 to 18 years, and sorted them by how much they sat and how active they were.

• Sat more than 8 hours, very active. People in the most active quarter, about 60 to 75 minutes a day of moderate activity, had no clear extra risk even when they sat over 8 hours a day (a hazard ratio of 1.04, too close to the lowest-risk group to call different).
• Sat more than 8 hours, inactive. People in the least active quarter who sat over 8 hours had 59% higher risk.
• Sat the least, inactive. People who sat under 4 hours a day but were in the least active quarter had 27% higher risk, which is worse than the people who sat all day and moved a lot.

TV was harder to cancel out. Watching 3 hours or more a day went with higher risk at every activity level except the top one, and even there the risk rose at 5 hours or more.

The simple version

Think of your day as 16 waking hours. The harm in sitting comes mostly from the hour of movement it crowds out, so the fix is to find that hour wherever it fits.

How many years moving gives back

The biggest US habits study, of 123,219 adults, found that compared with doing nothing, moving 3.5 to 6 hours a week went with half the death rate. Even under an hour a week went with 35% lower risk. In our calculator, a 50-year-old who does no exercise and starts moving 30 minutes a day gets back about 7 years on average.

Walking briskly counts, and so does anything that gets you breathing harder: cycling, swimming, dancing, yard work. Steps count too, and the famous 10,000 has a story of its own.