Adults who are insufficiently physically active across adulthood experience a significantly higher burden of chronic stress by midlife, according to a study published in Psychoneuroendocrinology. The findings suggest that regular physical activity is not just beneficial at isolated life stages, but plays a cumulative, protective role against long-term physiological stress.
Prolonged Stress Exposure
The research analysed data from 3,358 participants in the Northern Finland Birth Cohort 1966, a large, population-based study that has followed individuals from birth into adulthood. Participants were assessed at ages 31 and 46, allowing researchers to examine how patterns of leisure-time physical activity (LTPA) across adulthood relate to stress outcomes in midlife.
Participants were grouped according to their physical activity patterns over time: stable inactive, increased activity, decreased activity, or stable active. Chronic stress was measured using the concept of allostatic load – the cumulative “wear and tear” on the body caused by prolonged exposure to stress. This was assessed using two validated indices: a comprehensive 13-item measure and a shorter 5-item measure, both reflecting strain across multiple biological systems.
Increasing Activity Has Significant Benefits
The results showed that individuals who remained physically inactive or reduced their activity levels over time had a significantly higher allostatic load by midlife compared with those who remained consistently active. Notably, those who increased their physical activity during adulthood had stress levels comparable to participants who had been physically active throughout, suggesting it is never too late to gain stress-protective benefits from exercise.
Doctoral researcher Maija Korpisaari noted that both physical activity in youth and sustained exercise in adulthood contribute to lower stress burden later in life. Regular activity appears to improve the body’s ability to cope with stress well into midlife.
The authors caution that physical activity is only one part of the picture. Factors such as diet, alcohol consumption and sleep can influence stress outcomes and may blunt the benefits of exercise. They call for future research to include more detailed measures of real-world stress exposure to better understand how physical activity interacts with other lifestyle and environmental stressors over the life course.
