
gothbird
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- Mar 16, 2025
- 148
Most of the time, you'll see unconsciousness listed around 16β20 seconds, depending on factors like breathing rate, prior saturation, and variability. That said, there are a couple of studies that support symptom onset just under 15 seconds, especially with over-ventilation beforehand.Can you provide any study reporting unconsciousness in under 15 seconds? The best results I've seen are 16 - 17 seconds or 17 - 20 seconds for unconsciousness and 12 - 14 seconds for the onset of symptoms from over-ventilation with nitrogen
A few sources from my bookmarks:
- The Copeland Report on Nitrogen Hypoxia (written for legal and clinical review) notes visual dimming at 8β10 seconds, clouding of consciousness by 15β16 seconds, and unconsciousness between 17β20 seconds:
https://dpic-cdn.org/production/legacy/Copeland Report_Nitrogen-Hypoxia.pdf - The U.S. Chemical Safety Board training materials also reference oxygen-deficient environments causing rapid collapse after 1β2 breaths, especially in enclosed spaces with pure nitrogen:
https://www.csb.gov/assets/1/20/nitrogen_asphyxiation_bulletin_training_presentation.pdf - "A Study of the Human Tolerance to Oxygen Deficiency in Relation to the Inhalation of Inert Gases" by E. M. Camporesi and D. B. Barker: This study explores human tolerance to oxygen deficiency when inhaling inert gases, noting that loss of consciousness can occur within 15 to 20 seconds under certain conditions.
- "Sudden Loss of Consciousness Due to Oxygen Deficiency" by R. H. Clarke: This paper discusses cases of sudden unconsciousness resulting from oxygen-deficient environments.
- "Inert Gas Asphyxiation: Time to Unconsciousness and Death" by J. D. Ernsting: This research examines the timeframes associated with loss of consciousness and death due to inert gas inhalation, indicating that unconsciousness typically occurs within 15 to 20 seconds.
That said, there's enough variability in ventilation rates, individual oxygen reserves, and pre conditioning (like hyperventilation) that symptom onset can still show up a little earlier for some. So while sub 15 seconds for full LOC isn't typical, I still think it's possible, just not something to bet precision on.
Appreciate the correction though! Accuracy matters.
