Raising your heels and toes in quick succession could lower your risk of suffering a blood clot in the legs, said Dr Chris.
The exercise could be used for long-haul aeroplane journeys and train journeys, as well as while sat watching TV, he added.
Sitting for long periods of time could cause a deep vein thrombosis (DVT), that develops in a vein in the body. It can also lead to a “life-threatening” pulmonary embolism – a condition that’s caused by a blockage in the blood vessel that delivers blood to the lungs from the heart.
“We know about long-haul flights, long train journeys, or even being hospitalised – they get you out of bed quickly, they get you moving,” said Dr Chris.
“[Scientists] found that when you’re sitting watching television, you’re not really moving.
“A lot of people sit with their legs curled under as well, and the average person watches about three to four hours of television a night. So, you’ve got very little mobility there and the blood is collecting.”
The best way to avoid these blood clots was to get up and walk around, or put an exercise bike in your living room while watching TV, Dr Chris added.
Dr Chris demonstrated a quick and easy exercise that you could do while sitting down, if you didn’t want to walk around or exercise while watching television.
“The simplest thing to do – and I want to demonstrate this exercise – this is good for apple doing long haul flights, long trains journeys and watching television at home,” he said.
“Heels up, toes up, heels up, toes up, heels up, toes up.”
The exercise contracts muscles in the calves and lower leg, and blood is squeezed up toward the heart, without the threat of clotting, he added.
Dr Chris’s comments came after that sitting in front of the TV for too long increased the risk of potentially fatal blood clots by 70 per cent.
While watching TV itself isn’t necessarily bad for health, snacking and sitting for long periods of time could trigger a vein condition known as venous thromboembolism, they said.
The condition begins in a vein, and includes two types of blood clots – DVT, and pulmonary embolism.
About 25,000 people in Britain die from the condition every year.