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Increasing physical activity to the levels of the most active quarter of Americans over 40 could add up to 11 years to a person’s life, according to a study using data from national health surveys.
Walking just over two and a half hours daily could significantly cut the risks of chronic diseases and boost life expectancy. The study highlights the need for public health strategies to build environments that support active lifestyles.
Longevity Benefits of Physical Activity
If every American over age 40 were as physically active as the top 25% of the population, they could potentially live an additional 5 years, according to a modeling study published today (November 14) in the British Journal of Sports Medicine.
The study also estimates that if the least active individuals matched the activity levels of the most active, they could gain nearly 11 extra years of life.
While it is well-established that low levels of physical activity increase the risk of diseases like heart disease and stroke—and contribute to premature death—the specific impact of physical activity on lifespan within groups, such as Americans over 40, has not been fully understood.
Research Methodology and Activity Tracking
To explore this, researchers developed a predictive model that assesses how varying levels of increased physical activity could impact life expectancy.
This model used physical activity risk estimates from data collected by activity trackers in the 2003–2006 National Health and Nutritional Examination Survey for people over 40, combined with 2019 U.S. Census population data and 2017 death records from the National Center for Health Statistics.
Detailed Findings on Activity Levels and Lifespan
The total physical activity of the most active 25% of Americans over the age of 40 was equivalent to 160 minutes of normal paced walking at 4.8 km/(3 miles)/hour every day.
Based on this, the researchers estimated that if all the over 40s in the US matched this level of physical activity every day, their average lifespan would increase by just over 5 years, boosting life expectancy at birth to nearly 84 years from 78.6 years.
And if the least physically active 25% of the population matched the levels of the most physically active 25%, they would need to clock up an extra 111 minutes of walking at 4.8 km/hour every day (or equivalent effort). But this could increase their life expectancy by nearly 11 years, the estimates suggest.
Potential Health Gains From Increased Physical Activity
The greatest gain in life for every hour walked was seen among the least physically active, among whom each extra hour of walking could add 376 minutes to their life expectancy—equivalent to around 6 hours. Gains to life expectancy decreased as physical activity rose and on average every extra hour walked could add 169 minutes (2 hours and 49 minutes) to life expectancy.
This is an observational study, and as such, can’t establish cause and effect, and the researchers acknowledge various imitations to their findings. For example, the predictive model they used may have underestimated or overestimated the benefits of physical activity for Americans, because of the research findings on which it drew.
Conclusion and Recommendations for Public Health
However, they nevertheless suggest that increased investment in physical activity promotion and the creation of living environments that foster physical activity have the potential to yield large gains in life expectancy for Americans at the population and individual levels.
“Our findings suggest that [physical activity] provides substantially larger health benefits than previously thought, which is due to the use of more precise means of measuring [it],” they write.
“The greatest gain in lifetime per hour of walking was seen for individuals in the lowest activity quartile where an hour’s walk could add an impressive 6 hours to life.”
However, the researchers acknowledge that increasing physical activity at the population level is a complex task that requires a systems-wide approach.
“Infrastructure measures that encourage active transport, walkable neighborhoods, as well as green spaces might be promising approaches to increase physical activity and resultant healthy life expectancy at the population level,” they suggest.
Reference: “Physical activity and life expectancy: a life-table analysis” 14 November 2024, British Journal of Sports Medicine.
DOI: 10.1136/bjsports-2024-108125
