People who spend years not getting enough exercise carry a significantly higher burden of long-term stress by middle age, according to a study published in the journal Psychoneuroendocrinology. The authors highlight that those who stay active appear to be protected from that buildup.
The study, a collaboration between the University of Oulu and the Oulu Deaconess Institute Foundation in Finland, followed more than 3,300 people from age 31 to 46, tracking their exercise habits and measuring the cumulative strain that long-term stress places on the body, a concept known as allostatic load.
We know that exercise is good for us, but the link between long-term physical activity patterns and the body’s overall stress burden is still poorly understood. This study, which drew on data from the Northern Finland Birth Cohort 1966, set out to explore exactly that.
The findings were clear:people who consistently fell short of the World Health Organisation’s recommended levels of physical activity for long periods showed higher stress burden by midlife compared to those who met the guidelines. Those whose activity levels declined over time also showed increased stress burden.
Encouragingly, people who became more active during adulthood, even if they hadn’t been before, showed stress burden levels similar to those who had been consistently active. It suggests that it’s never too late to benefit from taking up exercise in adulthood. “The results suggest that the importance of physical activity is not limited to individual life stages; rather, regular exercise throughout adulthood may protect the body from the harmful effects of long-term stress,” said Doctoral Researcher Maija Korpisaari.
The stress burden was measured using multiple combinations of biological markers, and the results held up consistently across different ways of measuring it, strengthening confidence in the findings. “In terms of stress burden, both the amount of physical activity in youth and in adulthood are important. Regular physical activity in adulthood appears to help the body cope with stress even into midlife,” added Korpisaari.
The researchers say more long-term studies are needed to better understand how physical activity influences the body’s stress systems at different stages of life, and to refine the best ways of measuring that impact.
Korpisaari M, Leinonen AM, Ikäheimo T, Tulppo M, Seppänen M, Keinänen-Kiukaanniemi S, Korpelainen R, Farrahi V, Lankila T. Association of longitudinal changes in physical activity with allostatic load in midlife. Psychoneuroendocrinology. 2026 Feb;184:107725. doi: 10.1016/j.psyneuen.2025.107725.