The Mammalian Dive Response

1458 WordsOct 21, 20066 Pages
Abstract The presence of a dive response in humans when the face is submerged in water was studied. A lot of mammals have shown to exhibit a dive response known as the mammalian dive reflex. During this reflex bradycardia, a slowing of the heart rate, is shown. In this study, human subjects were put through various tests to determine if humans also exhibit bradycardia. Subject's heart rates were measured while breathing normally, while holding breath and while holding breath with face submerged in water. The results showed that there was a significant decrease in heart rate while submerged in water as compared to normal breathing or holding breath out of water. Many other studies have been done that agree with the results found in…show more content…
This shows that there are some other affects of the mammalian dive response other than just bradycardia. When looking at a study done by Hochachka and Mottishaw on dive responses of phocids and otariids, there was quite a different take on the dive response shown. These animals show a lot more advanced dive response with an increased number of factors playing a role than what humans have. Although, there are some mechanisms that humans do share with whales, penguins and seals (Seedhouse 2002). These mechanisms include vasoconstriction, preferential shunting/blood shifts/thoracic filling, and bradycardia (Seedhouse 2002). Studying these other factors could have improved the results of this paper. Another variable that would have made this study better would have been one that involved water temperature. Colder water has been reported to show a lot more of a decrease in heart rate. This could have had an affect on the data recorded in this study. Another important factor would have been to focus also on vasoconstriction. Sterba and Lundgren found that there was a much greater affect on blood flow then heart rate change. Schagatay and Andersson also tested different levels of fitness in humans to see if this had any affect on the diving response. This showed that the better shape a person is in results in a slightly increased diving response. Any of these extra tests would have made this paper stronger. The overall results showed a dive
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