Exploring the Mammalian Dive Reflex in Humans

Mammalian Dive Reflex

Purpose

The purpose of this experiment is to observe the mammalian dive reflex in 2 subjects’ measuring their heart rate, blood pressure, and % arterial oxygen saturation (SpO2).

Introduction

All mammals, including humans, have the physiological means to survive the submersion of cold water for a greater period of time. This is called the mammalian dive reflex. Taking the subjects heart rate, blood pressure, and percentage of arteriole oxygen saturation shows the cardiac and vascular changes within the sympathetic and parasympathetic nervous system. In this study two human subjects underwent experiments showing how the body responds when the face is submerged in various temperature waters (room temp, warm and cold water).

Although the three variables including water, position, and apnea were able to activate the diving reflex. It was the water alone that primarily triggered the result. Tables 1-3 shows that just breathing alone tiggered the diving reflex with the heart rating having a slight decrease. However in table 9 when the face was submerged in water, you could see a considerable decrease in the body’s physiological response. This response suggests that when the trigeminal nerve was activated, it relayed a signal to the brain stem within the parasympathetic nervous system, which caused bradycardia (slowing of the heart rate). This data shows that the cold water was the primary source in this reaction of the diving reflex. Although, subject 2’s heart rate only changed slightly, this could be due to either internal or external factors including, students making to much noise, the subject not being familiar with using a mask, or not feeling well that day. Some room for improvements could have been to have younger or older volunteers, work in smaller groups, or to have students be in a less distracting