Key result
Water immersion per se causes about one-third of the diving bradycardia in ducklings, with heart rate falling rapidly in the first few seconds regardless of head position or oxygen pre-breathing.
This preclinical study demonstrates that approximately one-third of the diving bradycardia observed in ducklings is directly attributable to water immersion itself, independent of respiratory or head position factors.
Water immersion contributes independently to bradycardia in ducklings; extends diving reflex mechanisms but leaves human translation open.
Experiments were done to clarify the contribution of water immersion per se to the cardiac chronotropic response to enforced submergence in ducklings. Four protocols were used in which one or more of the factors claimed to affect diving heart rate were controlled. Heart rate fell rapidly in the first few seconds of submergence in all protocols. This initial fall was unaffected by changes in head position or by breathing 100% oxygen for 5 min before diving. Also, sudden withdrawal of input from lung receptors or cessation of activity in central respiratory neurones did not affect onset of diving bradycardia. We conclude that about one-third of diving bradycardia in ducklings is caused by water immersion per se.
No takes yet. Share an insight, caveat, or question.
Jones et al. (1982) studied this question. Water immersion per se during enforced submersion was evaluated on Cardiac chronotropic response (diving bradycardia). Water immersion per se causes about one-third of the diving bradycardia in ducklings, with heart rate falling rapidly in the first few seconds regardless of head position or oxygen pre-breathing.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: