The world is just days away from the greatest global showcase of elite sport.
But while a few thousand athletes will be pushing their bodies to the limit, most of the world will be watching on TV, sitting inactive for hours on end.
In a series of articles in the Lancet timed to coincide with the Olympics, researchers from 16 countries set out the scale of the health burden created by physical inactivity. You can read more about the research here.
The scientists say they are neither Olympics kill-joys nor are they advocating punishing gym sessions. As Pamela Das from the Lancet puts it: "It is not about running on a treadmill, whilst staring at a mirror and listening to your iPod."
There’s nothing wrong with going to the gym of course, but the aim is to encourage everyone to build physical activity into their daily lives, such as by walking, cycling, swimming, gardening or doing any sport they enjoy.
The trouble is, all that sounds familiar. We all know we should move more and sit less.
Despite that, one in three adults worldwide fails to do the recommended 150 minutes of moderate aerobic physical activity per week. In the UK two out of three adults don’t manage it. The guidance is here.
So rather than stressing the health benefits of exercise, the Lancet researchers have opted to show the harm caused by inactivity. They estimate lack of exercise is responsible for about 5.3m deaths a year – about the same number as smoking.