Lennert Veerman, Griffith University

• Americans over the age of 40 could live an extra 5.3 years if all were as active as the top 25% of the population

• For the least active 25% of Americans aged 40+, an extra hour’s walk could add an average of 6.3 hours of additional life expectancy.

According to a new study led by Griffith University researchers, if everyone in the United States population was as active as the top 25 per cent, individuals over 40 could add five years to their lives.  

Physical activity has long been recognized as beneficial for health; however, estimates have varied regarding the extent of benefits derived from specific amounts of activity, both for individuals and populations.

This latest study used accelerometry to gain an accurate view of the population’s physical activity levels instead of relying on survey responses, as in other studies. It found that the benefits were around twice as substantial as previous estimates.  

It found the most active quarter of people in the community had a 73 per cent lower risk of death than their least active counterparts. 

For the least active quartile, a one-hour walk could potentially provide around six additional hours of life.  

Lead researcher Professor Lennert Veerman said this least-active cohort had the most significant potential for health gains.  

“If you’re already very active or in that top quartile, an extra hour’s walk may not make much difference as you’ve, in a sense, already ‘maxed out’ your benefit,” he said.   

“If the least active quartile of the population over age 40 were to increase their activity level to that of the most active quartile, however, they might live, on average, about 11 years longer.  

“This is not an unreasonable prospect, as 25 per cent of the population is already doing it.  

“It can be any type of exercise but roughly the equivalent of just under three hours of walking per day.” 

The research team suggested low levels of physical activity could even rival the adverse effects of smoking, with other research finding each cigarette could take 11 minutes from a smoker’s life.  

By extension, a more active lifestyle could also offer protective effects against heart disease, stroke, certain cancers, and other chronic illnesses. The study’s findings highlight a need for national physical activity guidelines to be revisited using these methods.  

Dr Veerman said physical activity had been vastly underestimated in its capacity to improve health outcomes, suggesting even modest increases in movement could lead to significant life-extension benefits.  

“If there’s something you could do to more than halve your risk of death, physical activity is enormously powerful,” he said.  

“If we could increase investment in promoting physical activity and creating living environments that promote it, such as walkable or cyclable neighbourhoods and convenient, affordable public transport systems, we could increase longevity and reduce pressure on our health systems and the environment.”