IJSRP, Volume 5, Issue 3, March 2015 Edition [ISSN 2250-3153]
Ojashwi Nepal, Kalpana Sharma, Sunam Mander, Sarina Kusma
Humans like most other air-breathing vertebrates exhibit a syndrome known as diving reflex. In man, facial immersion has shown to be sufficient stimulus for onset of reflex. During immersion there is significant slowing of heart rate, and at the periphery, blood vessels undergo constriction. In all animal, diving reflex is triggered specifically by cold water contacting the face. Water that is warmer than 21 °C (70 °F) does not cause the reflex, and neither does submersion of body parts other than the face. The precise mechanism for this effect has been debated. The heart rate and blood pressure is compared here in this study to determine the difference in autonomic changes during breath holding and diving reflex. In this study, 80 healthy subjects (38 males and 42 females) from 18 to25 years were examined to evaluate the effect of facial cooling and apnea in development of diving reflex. Facial immersion was accomplished through the voluntary action of subject into a shallow water bath. The subject was told to remain submerged as long as it was comfortably possible to do so. Throughout experiment, water temperature was maintained. Mean of heart rate and standard deviation was calculated for each of the experimental conditions. At rest, mean heart rate was 77.7±10.95, mean heart rate during hands submersion with breath hold was 70.5±13.63. Mean heart rate with face submersion was found to be 61.46±14.32. Diastolic blood pressure is compared at rest and facial submersion, while breath holding. There is increase in diastolic blood pressure during facial submersion while breath holding (84.85±16.98) than that at rest (74.04±9.78). The result obtained shows heart rate decreases during facial submersion with breath holding compared to that at rest and blood pressure increases during facial submersion with breath holding.