Abstract

ABSTRACT Background: Key components of the diving response (apnoea, bradycardia, peripheral vasoconstriction, redistribution of cardiac output etc.) were found in essentially all species analyzed, and were generally taken to be biological adaptations. Aims &
Objective: To determine change in the heart rate (HR) in a simulated dive experiment in human volunteers.
Materials and Methods: In this study, 30 healthy adult male volunteers without cardio-respiratory illness participated. They held their breath in air and then in water at around 15⁰C in a plastic tub for 30 seconds at our laboratory. Their HR was measured using an automated instrument (Schiller’s multipara monitor). st nd
Results: 1 part of experiment (breath holding in air) has shown no significant change in HR during 30 sec, while in the 2 part (breath holding in water) has shown a significant change in the heart rate – on an average, from 108.97 to 70.8; with a difference of st nd 38.17 (p <0.0001). The comparison of the difference in HR at 0 and 30 seconds of the 1 and 2 part of the experiment has shown that an average difference in HR was 3.2 in breath holding in air and 38.17 in breath holding in water, with a difference of 34.97 (p<0.01) between the two parts of the experiment at the 30s. Conclusion: The study indicated that a significant decrease in HR can occur during a dive.