If your job has you sitting for the best part of eight hours a day, you’ll need to spend an extra hour walking 5.6km or cycling 16km to cancel out the negative health effects.

An international analysis led by Professor Ulf Ekelund from the Medical Research Council Epidemiology Unit at the University of Cambridge – and published in The Lancet journal – examined data from one million men and women from countries including Australia.

The researchers wanted to answer a question: “if an individual is active enough, can this reduce, or even eliminate, the increased risk of early death associated with sitting down?”

The good news is it can. The bad news is that “as many as three out of four people in the study failed to reach this level of daily activity.”

“A typical day for many people is driving to work, sitting in an office, driving home and watching TV,” the researchers said.

They found that desk-bound workers and sedentary commuters need “60 to 75 minutes” of “moderate” exercise a day to offset eight hours of sitting.

The researchers define moderate intensity exercise as “walking at 3.5 miles/hour or cycling at 10 miles/hour”. That means covering 5.6 kilometres in an hour by walking, or 16km in an hour on a bike.

“There has been a lot of concern about the health risks associated with today’s more sedentary lifestyles,” Professor Ekelund said.

“For many people who commute to work and have office-based jobs, there is no way to escape sitting for prolonged periods of time.

“For these people in particular, we cannot stress enough the importance of getting exercise, whether it’s getting out for a walk at lunchtime, going for a run in the morning or cycling to work.

“An hour of physical activity per day is the ideal, but if this is unmanageable, then at least doing some exercise each day can help reduce the risk.”

The researchers said that no exercise was an even bigger concern than prolonged sitting.

“The greatest risk of early death is for those individuals who are physically inactive, regardless of the amount of time sitting,” the researchers said.

“They are between 28 percent and 59 percent more likely to die early compared with those who were in the most active quartile – a similar risk to that associated with smoking and obesity.”

If some of this sounds familiar, it probably is: last year, Dr David Agus – who treated Steve Jobs – laid out how he believed the workplace is killing us.

Dr Agus used technology – health wearables – to track how much he sat and moved in his day-to-day life.

Shocked at the result, he bought a treadmill and took a number of other steps to change his habits.

This latest study provides further evidence of our need to move more if we plan to live well beyond our working years.