Reducing the amount of time spent sitting down to three hours a day could increase life expectancy by two years, according to new research.
Scientists in America also claimed that by cutting down the amount of television watched to less than two hours each day could add an extra 1.4 years.
The research, published in BMJ Open, used survey data to calculate how much time people in the USA spent sitting down and watching television, and used previously published research into sedentary behaviour to make calculations about the impact on life expectancy.
It said that adults should try to be active every day, and should undertake 150 minutes of moderate intensity exercise, such as cycling, or 75 hours of more active exercise, such as running, each week.
Natasha Stewart, senior cardiac nurse at the British Heart Foundation, said: '[This research] highlights what we already know about sedentary behavior being a risk factor for developing heart disease. And recent UK guidelines suggested we should all minimise the time we spend sitting down.
'We all need to be regularly active to keep our hearts healthy. So whether it's by walking to the local shop rather than driving, or playing sport rather than watching it on TV, there are lots of ways to be more active and improve your health.'