"Research into lifestyle factors such as lack of physical activity, poor diet, drinking alcohol, and smoking, tends to focus on the harms these do to health," said study researcher Dr. Paul Kelly from the University of Edinburgh in the UK.
"This helps create a narrative to try and prevent and reduce these behaviours," Kelly added.
In their study, the research team used a number known as the Prevented Fraction for the Population - in this case, the proportion of deaths that were prevented because people are physically active.
The team looked at previously published data for 168 countries, on the proportion of the population meeting World Health Organisation (WHO) global recommendation of at least 150 minutes of moderate-intensity aerobic activity throughout the week, or 75 minutes of vigorous-intensity activity, or an equivalent combination.
By combining these data with estimates of the relative risk of dying early for active people compared to inactive people, the authors were able to estimate the proportion of premature deaths that were prevented because people are physically active.
They found that globally, due to physical activity the number of premature deaths was an average (median) of 15 per cent lower than it would have been -- 14 per cent for women and 16 per cent for men -- equating to approximately 3.9 million lives saved per year.
The findings showed that in low-income countries, an average of 18 per cent of premature deaths was averted compared to 14 per cent for high-income countries.
The researchers said that by showing how many deaths are averted, it might also be possible to frame the debate in a positive way and this could have benefits to advocacy, policy and population messaging.
"Whether that's sports or a gym or just a brisk walk at lunchtime - but by focusing on the number of lives saved, we can tell a good news story of what is already being achieved," said study researcher Tessa Strain from the University of Cambridge in the UK.
"We hope our findings will encourage governments and local authorities to protect and maintain services in challenging economic climates," the authors wrote.