Honors Theses
Date of Award
5-2026
Document Type
Undergraduate Thesis
Degree Name
BS
Department
Chemistry
Faculty Mentor
John Shelley-Tremblay, Ph.D.
Advisor(s)
Richard Sykora, Ph.D., Jason Coym, Ph.D.
Abstract
Cortisol is a key biomarker of hypothalamic–pituitary–adrenal (HPA) axis activity and is commonly measured using salivary, serum, urinary, or hair matrices. However, recent advances in wearable biosensing technologies have generated interest in sweat as a minimally invasive medium for continuous cortisol monitoring. The present study evaluates whether cortisol measured in sweat demonstrates biological convergence with salivary cortisol and whether psychological stress variables influence sweat-based cortisol measurement reliability. Fifty-four college-aged participants completed baseline salivary cortisol collection, controlled passive heat exposure to induce sweating, post-exposure salivary cortisol collection, and sweat sampling from the forehead and upper back. Participants also completed validated psychological questionnaires assessing trauma exposure, perceived stress, depressive symptoms, anxiety, life stress, and medication status. Moderate positive correlations were observed between salivary and sweat cortisol concentrations across anatomical sites (r = 0.36–0.48), and regression analyses indicated that salivary cortisol significantly predicted sweat cortisol levels, accounting for approximately 13– 23% of the variance in sweat cortisol concentrations. Sweat cortisol concentrations did not significantly differ between forehead and upper back sampling sites, suggesting relative consistency across eccrine regions. Across psychological subgroup analyses no significant differences in cortisol concentrations were observed across either salivary or sweat matrices. These findings suggest that sweat cortisol measurement is not strongly confounded by psychological history within a non-clinical population. Participants reporting selective serotonin reuptake inhibitor (SSRI) and serotonin– norepinephrine reuptake inhibitor (SNRI) antidepressant use exhibited significantly lower forehead sweat cortisol concentrations compared to non-users despite no corresponding differences in salivary cortisol. This finding suggests that antidepressant medication status may influence sweat cortisol output and represents a potential correction factor for wearable sweat cortisol sensing systems. Collectively, these findings provide physiological validation for sweat cortisol as a minimally invasive biomarker of HPA axis activity and support its potential application in wearable stress monitoring technologies. Further research is needed to characterize medication effects and to evaluate sweat cortisol monitoring in real-world continuous sensing environments.
Recommended Citation
Baker, Isabella, "Sweat Cortisol as a Non-Invasive Marker of HPA Axis Activity: Evidence for Biological Convergence and Pharmacological Sensitivity" (2026). Honors Theses. 130.
https://jagworks.southalabama.edu/honors_college_theses/130
Included in
Applied Behavior Analysis Commons, Behavior and Behavior Mechanisms Commons, Biochemical Phenomena, Metabolism, and Nutrition Commons, Biological Psychology Commons, Human Factors Psychology Commons