Stress Did Not Release Stored THC Into the Bloodstream of Regular Cannabis Users
Despite causing measurable stress and mild fat breakdown, cold water immersion did not increase blood THC levels or produce intoxication in 15 regular cannabis users.
Quick Facts
What This Study Found
Cold water immersion (10 minutes at 10 degrees C) produced a small but significant stress response (increased heart rate, blood pressure, decreased calmness) and increased plasma free fatty acids and glycerol. However, neither plasma THC nor its metabolite 11-COOH-THC increased, and no cognitive impairment or subjective intoxication was observed.
Key Numbers
N = 15 (9 female). Cannabis use: 5.0 days/week. CWI: 10 min at ~10 degrees C. Significant increases in HR, systolic BP, FFA, and glycerol. No change in plasma THC, 11-COOH-THC, cognitive function, or subjective drug effects.
How They Did This
Single-arm trial with 15 regular cannabis users (5+ days/week, 9 female). Participants underwent cold water immersion as a stress intervention. Plasma cannabinoids, cognitive function, subjective drug effects, heart rate, blood pressure, and lipolysis markers were measured before, shortly after, and 2 hours after immersion.
Why This Research Matters
Animal studies suggested that stress-induced lipolysis could release fat-stored THC into circulation, potentially causing unexpected intoxication. This study found no evidence of this phenomenon in humans, which is reassuring for regular cannabis users in stressful situations.
The Bigger Picture
The idea that stored THC could be spontaneously released during stress, exercise, or fasting has generated concern. This study provides the first controlled human evidence that brief acute stress does not release clinically meaningful amounts of stored THC.
What This Study Doesn't Tell Us
Small sample (n=15). Only one type and duration of stress tested. The stress response and lipolysis were modest; more intense or prolonged stress might produce different results. Regular users only; results may not apply to occasional users with different fat storage patterns.
Questions This Raises
- ?Would more intense or prolonged stress produce THC release?
- ?Does exercise-induced lipolysis (which is more sustained) have different effects?
- ?Could this mechanism operate in individuals with higher body fat percentages?
Trust & Context
- Key Stat:
- Zero increase in blood THC despite stress-induced fat breakdown
- Evidence Grade:
- Small pilot study with controlled design. Provides initial human evidence but requires replication with different stress intensities and populations.
- Study Age:
- Published in 2025.
- Original Title:
- Does acute stress induced via cold water immersion increase blood THC concentrations in regular cannabis users?
- Published In:
- Psychopharmacology, 242(12), 2785-2799 (2025)
- Authors:
- McCartney, Danielle(22), Levoux, Jordan, Gordon, Rebecca(10), Sharman, Laura, Walker, Katie, Arnold, Jonathon C, McGregor, Iain S
- Database ID:
- RTHC-07095
Evidence Hierarchy
A small preliminary study to test whether a larger study is feasible.
What do these levels mean? →Frequently Asked Questions
Can stress make you feel high from stored THC?
This study found no evidence of it. Despite causing measurable stress and fat breakdown, cold water immersion did not increase blood THC or produce any signs of intoxication in regular users.
Does this apply to drug testing?
The study measured plasma THC, not urine metabolites. While acute stress did not increase plasma THC, this does not address whether stress could affect urine drug test results, which measure different metabolites over longer windows.
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Cite This Study
https://rethinkthc.com/research/RTHC-07095APA
McCartney, Danielle; Levoux, Jordan; Gordon, Rebecca; Sharman, Laura; Walker, Katie; Arnold, Jonathon C; McGregor, Iain S. (2025). Does acute stress induced via cold water immersion increase blood THC concentrations in regular cannabis users?. Psychopharmacology, 242(12), 2785-2799. https://doi.org/10.1007/s00213-025-06833-8
MLA
McCartney, Danielle, et al. "Does acute stress induced via cold water immersion increase blood THC concentrations in regular cannabis users?." Psychopharmacology, 2025. https://doi.org/10.1007/s00213-025-06833-8
RethinkTHC
RethinkTHC Research Database. "Does acute stress induced via cold water immersion increase ..." RTHC-07095. Retrieved from https://rethinkthc.com/research/mccartney-2025-does-acute-stress-induced
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.