Related Experiment Videos
Left-ventricular performance in man during breath-holding and simulated diving
P M Gross1, R L Terjung, T G Lohman
1Department of Physical Education, University of Illinois, Urbana 61801, USA.
Undersea Biomedical Research
|December 1, 1976
Summary
Simulated diving, including breath-holding and facial stimulation, depresses left-ventricular (LV) performance in humans. These cardiovascular changes mirror those seen in natural divers, indicating a reduced stroke volume and cardiac efficiency.
Area of Science:
- Cardiovascular Physiology
- Human Diving Response
Background:
- The human diving response involves physiological adjustments to breath-holding and cold water immersion.
- Previous studies indicated a depression of left-ventricular (LV) performance in natural divers.
Purpose of the Study:
- To investigate if simulated diving (breath-holding and facial stimulation) induces LV performance depression in humans.
- To compare the cardiac response to simple breath-holding versus breath-holding with facial stimulation.
Main Methods:
- Noninvasive measurement of LV systolic time intervals (STI) in 15 adult males with diving experience.
- STI were recorded during supine rest, simple breath-holding (BH), and BH with cold facial stimulation (FS).
Main Results:
- Isovolumic contraction period increased significantly with both BH and FS.
- LV ejection time decreased during both BH and FS.
- Facial stimulation appeared to potentiate the observed cardiac depression.
Conclusions:
- Simulated diving significantly alters cardiac cycle components, suggesting reduced LV performance.
- The human diving response includes a depression in LV performance, similar to that in natural divers.
- Facial stimulation enhances the cardiac depression during simulated diving.