Walking more each day could help reduce healthcare costs, particularly among older adults, according to new research from Osaka Metropolitan University. The study suggests that the financial benefits associated with walking become increasingly pronounced with age. At the same time, the relationship between daily step counts and medical spending is far more complex than previously understood. Researchers also identified a point at which additional walking appears to offer little further reduction in predicted healthcare costs.

Although regular physical activity has long been linked to better health and lower medical expenses, much of the existing research has relied on participants reporting their own exercise habits. Previous studies have also tended to assume a straightforward relationship between activity levels and healthcare spending. To investigate whether this connection changes with age, Associate Professor Haruka Kato of Osaka Metropolitan University’s Graduate School of Human Life and Ecology examined objective walking data alongside actual health insurance records.

The research combined daily step counts collected through A-Smile, Osaka Prefecture’s official mobile health application, with administrative healthcare claims. It included 20,950 long-term app users aged 40 and above, covering 338,706 person-months between 2020 and 2023. Using a statistical approach known as generalised additive modelling, researchers were able to examine curved relationships between walking, age and predicted healthcare expenditure rather than assuming that every additional step produced the same financial benefit.

The findings revealed a striking difference between generations. Among middle-aged adults aged 40 to 64, predicted healthcare costs remained relatively stable regardless of daily step counts, suggesting that other factors played a greater role in determining medical spending. For adults aged 65 and older, however, the picture changed dramatically. Those recording fewer daily steps had substantially higher predicted healthcare costs, which declined sharply as walking activity increased. The association between walking and lower medical expenditure was therefore considerably stronger among older participants.

Despite these age-related differences, researchers discovered a remarkably consistent threshold. Predicted healthcare costs generally stopped declining once participants reached approximately 11,000 steps per day. The estimated plateau occurred at 11,317 steps for middle-aged adults and 10,612 steps for older adults. This suggests that while the potential financial benefits associated with additional walking vary considerably with age, the point at which those benefits level off remains broadly similar. The findings describe statistical associations rather than proving that increasing daily steps directly causes healthcare spending to fall.

“Our findings suggest that promoting walking among older adults could substantially contribute to reducing healthcare expenditures because predicted costs are far more sensitive to daily steps in this group,” said Dr Kato. The research also offers a way to estimate how predicted medical costs change with different walking levels at different ages. To make the findings more accessible, Dr Kato has developed an interactive online model that allows users to explore predicted healthcare expenditure and its confidence intervals according to age and daily step counts within the study’s range.

More information: Haruka Kato et al, Non-linear association between mHealth-measured daily steps and subsequent healthcare expenditures among long-term app users in Osaka, Japan, SSM – Population Health. DOI: 10.1016/j.ssmph.2026.10195

Journal information: SSM – Population Health Provided by Osaka Metropolitan University