Want to slow down ageing? Stand up and get active
A sedentary lifestyle has been linked to a host of diseases, from obesity to heart problems and diabetes.
Now, sitting for too many hours is also found to cause ageing.
In the study, published in the American Journal of Epidemiology, scientists traced sitting's impact on the chromosomes.
Blood samples were taken from nearly 1,500 older women - all enrolled in the Women's Health Initiative, a long-term study of chronic diseases in post-menopausal women.
The scientists focused on the tips of the tightly-packed DNA in every cell. Also known as telomeres, their lengths indicate how old a cell is.
DON'T SIT ON IT
Among those who didn't get the daily half hour of exercise, women who spent more time sedentary (about 10 hours or more) had shorter telomeres - an estimated eight years of cell ageing - as compared to those who sat less every day.
This means that inactive women who spent more time sitting were about eight years older, on average, than those who were inactive but spent less time sedentary.
There was no such link in women who got their daily recommended exercise, which suggests that physical activity might counteract the telomere-shortening that occurs with ageing.