What Researchers Did
Researchers investigated heart rate responses to breath-holding with and without face immersion in four male subjects during a dry saturation dive to a simulated depth of 580 feet (18.6 ATA).
What They Found
They found a significant linear correlation between the maximal bradycardial response and ambient pressure for simple breath-holding (r=0.08, P less than 0.05) and 31 degrees C face immersion (r=0.91, P less than 0.01). The thoracic conductive volume (TCV) was generally higher at depth, suggesting a mechanical effect from increased TCV contributes to pressure-dependent breath-holding bradycardia.
Canadian Relevance
This study has no direct Canadian connection.
Study Limitations
A significant limitation of this study is the very small sample size of only four male subjects.