BBC News
A lack of exercise is now causing as many deaths as smoking across the world, a study suggests.
The report, published in the Lancet to coincide with the build-up to the Olympics, estimates that about a third of adults are not doing enough physical activity, causing 5.3m deaths a year.
That equates to about one in 10 deaths from diseases such as heart disease, diabetes and breast and colon cancer.
Researchers said the problem was now so bad it should be treated as a pandemic.