October 17, 2025

#36: Does Stress Really “Stay in the System” for Three Days?

34 minutes

One of the most common questions Dr. Kristina Spaulding hears is whether stress “stays in the system” for three days. In this episode, she digs into what that really means, what the research shows, and why the truth is more complex than a simple yes or no.

She begins with the biology of the stress response—how the HPA axis and sympathetic nervous system work together, the roles of cortisol and corticosterone, and why not all stress is bad. Then she takes on the central question: how long does stress actually last? You’ll learn how long it typically takes for stress hormones to peak and return to baseline, and the many factors that influence recovery, making exact estimates of the duration of the stress response extremely difficult.

Dr. Spaulding also explores sensitization and cross-sensitization—how prior stress can make animals more reactive to future challenges, even entirely different ones. This has big implications for understanding anxiety, PTSD, and the impacts of stress on behavior. Finally, she discusses chronic and developmental stress and why a blunted stress response doesn’t necessarily mean an animal is “fine.”

The idea that stress lingers for three days is a myth. Hormones often normalize within hours, but the effects of stress—especially repeated or early-life stress—can last for days, weeks, or even a lifetime.

Resources:

Garcia, Arantxa, Octavi Marti, Astrid Valles, Silvina Dal-Zotto, and Antonio Armario. “Recovery of the Hypothalamic-Pituitary-Adrenal Response to Stress: Effect of Stress Intensity, Stress Duration and Prevention Stress Exposure.” Neuroendocrinology 72, no. 2 (August 2000): 114–25.

Belda, X., Rotllant, D., Fuentes, S., Delgado, R., Nadal, R., & Armario, A. (2008). Exposure to severe stressors causes long‐lasting dysregulation of resting and stress‐induced activation of the hypothalamic‐pituitary‐adrenal axis. Annals of the New York Academy of Sciences, 1148(1), 165-173.

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