II Holding of Breath Part Make sure your pulse-taker can still feel the pulse. N
ID: 81179 • Letter: I
Question
II Holding of Breath Part Make sure your pulse-taker can still feel the pulse. Now have the subject take one deep and then can his or her head down (as if in the water bath) and hold breath as they put 30-45 seconds should be long enough) his or her breath for as long 2. The timer should tap the subject on the back every 10 seconds (also saying the aloud intervals for the pulse-taker to hear), with several taps at 40 seconds to indicate they can stop holding their breath. The pulse-taker should measure the pulse from 10- 30 seconds during the and then again for 20 seconds starting about 5-10 seconds after the subject starts breathing again. The test subject should just breathe normally Chowever they feel they should breathe) after releasing their breath at the end of the breath-hold. 3. Record these data in Table 1 Part III The Diving Reflex I. Fill a large bowl or basin with water. Place several ice cubes in the bowl. Record the temperature ofthe water with the temperature probe ice the is The cold bowl of water should be placed in front of the subject. Record the temperature of the water. 2. Instruct the test subject to breathe normally. Measure their pulse for 20 seconds. As soon as the timer has ritten down the pulse, they should cue the subject to follow the same protocol as deep breath then put face down), only this time they should submerge their face to the temples in the cold water 3. The timer should (as before), tap on their shoulder every 10 seconds, saying the time out loud. The pulse- taker should measure the pulse from the 10-30 second time-interval then measure it again starting 5-10 and seconds after the subject starts breathing again. 4. Calculate the percent change in heart rate during the breath-holding and the simulated dive. Record this data in Table DATA AND CALCULATIONS Table 1: Heart Rate (HR) measurement before and during breath-holding in air and in cold water subject holding breath in air HR (beats per minute) holding breath in cold waler subject 5 subject 7 Percent change in heart rate can be calculated as follows: (HRduring HRbefore)/HR before) x 100Explanation / Answer
According to the test procedure and statistics that u have shown, I think the variable that could be responsible for the diving reflex is effect of temperature and location of skin sensors. When the forehead is cooled with a cold pack, it is sometimes possible to observe an initial increrase in heart rate, which then is followed by the bradycardia. Tachycardia might be a response to prevent the brain from cooling by circulating warm blood to the head. That might be the reason why tachycardia is observed initially, and bradycardia soon follows to help lower oxygen consumption. Since, only face to temples is submerged, it could mean the forehead is critical in sensing the presence of cold water, as the trigeminal facial nerves transmit the information to the brain which innervates the vagus nerve causing bradycardia. So, I would state a hypothesis that both temperature and location of skin sensors play a major role in regulating diving reflex.
In order to test this hypothesis for the effect of temperature, you may follow the same test prodecure as you have shown but with different range of water temperature. And as for testing the effect of location of skin sensors, you may try comparing with and without a face mask or by comparing full-face immersion with immersion of only the mouth and nose. You may also try comparing immersion of the face with immersion of some other body part, such as a hand or foot.
I hope you liked my answer.