Slumping in front of the TV every night after work can double the risk of deadly blood clots, research has suggested.
Experts found that sitting down for more than 41 hours a week outside of work increases the chance of suffering a blood clot in the lungs.
The study, on almost 70,000 women, found that those who sit for long periods are two to three times more likely to develop a clot than those who sit for less than 10 hours outside of work.
It is thought to be the first study of its kind to find a link between a sedentary lifestyle and pulmonary embolism.
But the researchers, writing in the British Medical Journal (BMJ), do say the risk is small and is only slightly higher than that for people who fly long haul or women who take the Pill.
A blood clot can travel from deep veins in the legs into the lungs, potentially causing death.
Symptoms of a clot include difficulty breathing, chest pain and coughing.