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Electrocardiogram during deep breath-hold dives by elite divers.
M Ferrigno1, B Grassi, G Ferretti
1Department of Anesthesiology, University of Miami, FL 33101.
Undersea Biomedical Research
|March 1, 1991
Summary
Elite divers exhibit significant heart rate reduction during breath-hold dives, with distinct bradycardia patterns compared to surface breath-holds. These responses are influenced by physiological factors like cold-water immersion and chest compression.
Area of Science:
- Physiology
- Marine Biology
- Cardiology
Background:
- Breath-hold diving elicits profound physiological responses, including the dive reflex.
- Understanding cardiac function during extreme breath-hold conditions is crucial for diver safety and performance.
Purpose of the Study:
- To investigate the heart rate response and arrhythmias in elite divers during deep-sea breath-hold dives.
- To compare cardiac responses during dives with non-immersed breath-holds.
Main Methods:
- Portable electrocardiogram (ECG) monitoring was employed in 3 elite divers during sea dives to 65m and 45m.
- ECG recordings were also obtained during maximal non-immersed breath-holds in divers and 8 control subjects.
Main Results:
- Divers experienced rapid heart rate decrease to 20-24 beats/min during dives.
- Surface breath-holds in divers showed slower bradycardia onset (28-36 beats/min).
- Arrhythmias, including premature complexes, coincided with lowest heart rates, potentially due to high vagal tone or cardiac distention/hypoxia.
Conclusions:
- Elite divers demonstrate a more consistent bradycardial response than controls.
- Differences in bradycardia patterns between dives and surface breath-holds may be attributed to immersion, compression, and blood redistribution.
- Vagal tone and hydrostatic pressure significantly influence cardiac rhythm during breath-hold activities.