It's long been known staying active can help boost heart health, especially as we age, but now experts say just walking for an extra five minutes a day could help you live longer.

A new study, analysing data from more than 135,000 adults, has revealed that adding just five minutes of exercise to your normal routine can slash the risk of death in the general population by an impressive 10 per cent. 

Even those who lead the most sedentary lifestyle, getting just two minutes of moderate-intensity exercise a day could see their risk of death drop by 6 per cent. 

The research, published in The Lancet, also found that reducing the amount of time a person spends sitting down by just half-an-hour could prevent around 7 per cent of deaths worldwide. 

They said: 'This 30-min change appears feasible in a real world setting, underscoring the large impact of realistic and achievable behavioural goals on population health.' 

Currently, physical inactivity is thought to be responsible for at least 9 per cent of deaths worldwide - but experts predict this number could be much higher.

In the study, researchers tracked 135,046 adults, aged around 63-years-old from Norway, Sweden, the US, and the UK who wore accelerometers to track physical activity. 

None of the participants had any evidence of chronic disease or mobility issues at the beginning of the study. 

Over a follow-up of eight years, the researchers discovered that reducing sedentary time in participants who spent more than eight hours a day not moving - comprising more than 70 per cent of the participants - was associated with a progressive lower risk. 

For example, encouraging those who spent more than 11 hours sedentary a day to get up and move for just half an hour was associated with risk reductions of around 10 per cent. 

Increasing this to an hour of physical activity slashed the risk by 25 per cent. 

Writing in The Lancet, the researchers said their study built on previous research that largely overlooked the fact that some individuals will not be able or willing to meet the recommended 150 minutes of physical activity a week. 

'Similarly, [previous studies have] assumed that the health benefits of changing from inactive to active are uniform for all individuals irrespective of their observed activity level,' they added. 

This is not comparable to real-world situations, the researchers say, where health conditions such as obesity, immobility and heart issues can all impact a person's ability to perform physical activity.  

However, the researchers did highlight a key limitation of their study: the results are limited to people age 40 and above.

This study was also observational, meaning that differences in death rates between different groups could-  in part - be caused by differences in other factors - not just physical activity alone. 

Professor Aiden Doherty, an expert in biomedical informatics at the University of Oxford, who wasn't involved in the current study, welcomed the researcher's findings.

'This is an excellent analysis, using the best available data sources that are a leap forward from the information that we have had available in the past,' he said. 

'While this might seem like yet another "more physical activity is good for you study", the authors have added important new details. 

'Healthcare systems are under enormous strain. This paper indicates that up to 10 per cent of all premature deaths might be prevented if everyone were to make small and realistic increases to their moderate-intensity physical activity of five mins a day.'

A similar study, spearheaded by experts at the University of Sydney, also published today, found that the risk of premature death could be slashed by at least 10 per cent if people slept for 15 minutes more a day, added just 1.6minutes of exercise to their daily routine and ate an additional half-serving of vegetables.

Dr Nicholas Koemel, trained dietician and expert in population health and study co-author, said: 'These findings suggest that focusing on combined small changes across multiple behaviours may offer a more powerful and sustainable strategy to improve health outcomes than targeting larger changes in an individual behaviour.' 

However, experts still recommend following the World Health Organisation's (WHO) guidance and aiming for at least 150 minutes of physical activity of this kind a week - or 75 minutes of vigorous activity. 

Dr Brendon Stubbs, an expert in the interaction between physical activity and mental health, added: 'This finding offers hope, especially to the least active, serving as an inspiring public health message.

'Even small daily tweaks to activity levels can make a meaningful difference, for instance a quick brisk walk, a few extra flights of stairs, or playing energetically with the (grand)kids.' 

It comes following landmark research last year which debunked the myth that 10,000 steps a day are necessary to prevent chronic conditions. 

A major review of 57 studies involving 160,000 adults found that for most health conditions, benefits tended to level off beyond 7,00 steps - providing a lower more realistic target for people to aim for.  

Sedentary lifestyles in the UK, with many spending their work hours deskbound then sitting on the tube or driving home to sit down in front of the TV, have been estimated to kill thousands each year. 

One 2019 estimate put the annual death toll at 70,000  people a year with the health issues caused costing the NHS £700million a year to treat. 

According to data published by the WHO, insufficient physical activity is the fourth most frequent cause of the death in the world, accounting for 3.2million deaths each year. 

Physical inactivity has been long linked to health problems like cardiovascular disease as well contributing to health problems like obesity, itself linked to an increased risk of type 2 diabetes and some cancers.