Hypothalamic-Pituitary-Adrenal (HPA) Axis Stress Response to a Laboratory-Based 10 % CO2 Challenge in Healthy Adults
Members of the Sleep and Health Research Lab: Harrison Dickens1, Jamie Walker1, and Dr. Ivan Vargas2, et al., recently published their study investigating how the hypothalamic-pituitary-adrenal (HPA) axis responds to a laboratory-based 10% CO2-inhalation challenge in healthy adults.
Findings indicated that inhaling CO2 can reliably activate multiple stress-response systems, involving neuroendocrine, autonomic, and emotional pathways.
Researchers evaluated salivary cortisol, heart rate, and fear/stress responses following a 5-minute CO2 challenge.
Results demonstrated (a) robust neuroendocrine, autonomic, and emotional activation in response to the CO₂ challenge, (b) significant increases in salivary cortisol for the majority of participants, and (c) sex differences and hormonal-status differences in cortisol reactivity.”
(Dickens et al., 2025)
University of Arkansas1
University of Notre Dame2