Just 22 minutes a day of brisk walking, cycling or running could offset the risk of death from too much sitting down.
In western countries like the UK, adults spend an average of nine to 10 hours a day sitting down – mostly during the time they are at work.
This sedentary lifestyle, which is difficult to avoid for office workers, boosts the chances of an early death, raising the risk of health problems from obesity and high blood pressure to diabetes and heart disease.
But doing more than 22 minutes a day of moderate and vigorous exercise ‘eliminates’ the risk of premature death which comes from sitting around too much, a study suggests.
Researchers looked at almost 12,000 people aged 50 and over from large health studies in Norway, Sweden and the US who were given fitness trackers to judge their physical activity.
In western countries like the UK, adults spend an average of nine to 10 hours a day sitting down – mostly during the time they are at work
They were followed up for an average of five years, during which time 805 people died.
The rate of deaths in sedentary people, compared to those who were less sedentary, and among those who got different amounts of exercise, produced interesting findings.
Researchers found being sedentary for more than 12 hours a day was linked to a 38 per cent higher risk of early death compared with being sedentary for eight hours a day.
But this was only the case for those who did less than 22 daily minutes of moderate to vigorous physical activity.
The study backs up the UK chief medical officers’ recommendation that people aim for 150 minutes of MVPA per week – roughly 21 minutes per day.
Dr Jakob Tarp, senior author of the study, said: ‘For many people it is not possible to be less sedentary in our everyday lives.
‘So this is hopeful that people can do a relatively small amount of physical activity and offset the effects of sitting down all day.
‘The important thing is that this achievable, for example through a brisk walk during your lunch break or after work, or through small changes during the day like taking the stairs instead of the lift.’
Moderate and vigorous exercise seems to work particularly well for people who are highly sedentary.
Doing 10 minutes a day of this kind of exercise, compared to zero minutes, reduced the risk of an early death by 15 per cent for people who were sedentary for less than 10-and-a-half hours a day.
But for those who were sedentary for longer, the risk of an early death fell much more strongly – by 35 per cent.
However light physical activity seemed only to be significantly effective for people who were more sedentary, for more than 12 hours a day.
The study, published in the British Journal of Sports Medicine, found getting more moderate or vigorous physical exercise is better than simply reducing the time spent sitting around.
The study authors took into account factors such as people’s age, BMI, and health problems including cardiovascular disease.
Examples of moderate activity include brisk walking, riding a bike, pushing a lawn mower, dancing or playing doubles tennis.
Vigorous activity, which makes you breathe hard and fast, includes running, sports like football and netball, skipping and walking up stairs.
Regina Giblin, senior cardiac nurse at the British Heart Foundation, said: ‘This research supports previous findings that show the negative effects of long periods sitting down and the positive impact of exercise.
‘It’s previously been shown that being sedentary for long periods increases the risk of heart and circulatory disease.
‘There are some simple tips that can help to spend less time sitting down.
‘Walking away from your computer screen at regular intervals, going for a walk or cooking a healthy meal from scratch are ways to incorporate active time into your day.’