Physical Activity, Metabolic Risk and the Primary Allostatic Load Mediators: An Explorative Study

Background: Chronic stress is associated with dysregulation of the body’s allostatic systems, contributing to increased allostatic load (AL) and adverse metabolic outcomes. Regular physical activity (PA) is considered a key protective factor that may attenuate AL by enhancing adaptive stress responses and supporting metabolic health. This study examined the differences between PA, primary mediators of AL, and metabolic risk markers in apparently healthy adults in Germany. Methods: Forty-six adults (18 - 45 years) were categorized into moderate intensity (regular PA: ≥ 150 min a week vs non-regular PA: ≤ 150 min a week) group according to current PA recommendations. Primary AL mediators were quantified by cortisol (ug/12h), epinephrine (ug/12h), norepinephrine (ug/12h), and dehydroepiandrosterone sulfate (DHEA-S: ug/ml). Group differences in primary AL mediators and metabolic risk markers were examined using the Mann–Whitney U test. Results: A significant group difference was observed for cortisol levels, with higher values in the regular PA group (p = 0.01) with a moderate negative effect size of r = -0.38. No statistically significant differences (p > 0.05) were found between groups for epinephrine, norepinephrine, DHEA-S, or metabolic risk markers, including triglycerides, blood pressure, body mass index (BMI), and high-density lipoprotein cholesterol (HDL-C). Conclusion: The findings suggest that regular PA may be associated with altered stress-regulatory activity, as reflected by differences in cortisol. While no statistically significant group differences were observed for metabolic risk markers, descriptive patterns indicate more favorable lipid profiles and potential variation in primary AL mediators at higher PA levels. Given the exploratory nature of the analyses and the small and unequal group sizes, these findings should be interpreted with caution and warrant confirmation in future studies with larger and more balanced samples.