Living a couch potato lifestyle could be shaving years of your life, new research has found.

Scientists have calculated that limiting the time we spend sat down to just three hours a day could add an extra two years onto our life expectancy. Similarly, if we cut the amount of TV we watch to just two hours we could add an extra 1.4 year to our lives.

These estimates have been made by US researchers, but experts in the UK have noted that the figures are too unreliable to predict personal risk. They also note that the targets are unfeasible, with many people trapped in lifestyles which require being sat for far more than three hours.

Prof David Spiegelhalter, an expert in risk calculations at the University of Cambridge, said: “This is a study of populations, and does not tell you personally what the effect of getting off the sofa might be.

“It seems plausible that if future generations moved around a bit more, then they might live longer on average. But very few of us currently spend less than three hours sitting each day, and so this seems a very optimistic target.”

Health bodies generally advise adults to take at least two-and-a-half hours of moderate-intensity aerobic activity such as cycling or fast walking every week, as well as engaging in some sort of muscle-strengthening exercise. But even those who manage to achieve these recommended goals are likely to be sat for most of the day.

This is why we should attempt to be more active in our free time. There is a growing body of research that suggests the more time we spend sitting, the less healthy we may be. Several studies have addressed the ‘couch potato’ lifestyle, linking it to conditions such as diabetes and heart disease as well as an increased overall risk of death.

Dr Peter Katzmarzyk and Prof I-Min Lee who carried out the review stress that their estimates are theoretical. “However, it does highlight what we already know about sedentary behaviour being a risk factor for developing heart disease. And recent UK guidelines suggested we should all minimise the time we spend sitting down,” he added.