Marine Mammal Diving Adaptations: Bradycardia Lab
Objective:
To design an investigation that tests whether or not humans exhibit bradycardia or slowing of the heart rate when the face is submersed in cool water.
In this lab you will need come up with a hypothesis and design an experiment that shows evidence of whether or not there is a measureable effect on the heart rate of an individual or bradycardia, which is one of three physiological effects that occur with the mammalian diving reflex. The diving response will be simulated in the lab by having a subject submerge their face in water for a period of time while measuring their heart rate.
Methods:
When conducting your experiment you will need to account for the individual’s resting heart rate and heart rate while holding their breath both in and out of the water.
You will need to have your methods approved before you begin. Your methods should include the following:
· How will you measure heart rate
· How will you measure resting heart rate
· Heart rate while holding breath
· How you will account for initial submersion “shock” on the heart rate
· Number of times you will repeat trials
· Number of individuals you will test
· Define your independent and dependent variables
Results Section:
The Results Section will need to include both data tables and graphs that are correctly labeled and easy to understand. Data tables at a minimum should include resting heart rates and averages, breath holding heart rates and averages, and heart rates with face immersion and averages. A written description should also be included for each data table and graph.
Analysis and Discussion:
In complete sentences and in paragraph form describe the following: How did the resting heart rate compare with Average Normal Heart Rate? What was the effect of breath holding on the pulse rate? What effect did placing the individual’s face in water have on the pulse rate? Are your findings statistically significant? What is the answer to your question?
Average Normal Variation in Heart Rate
Children: 72 – 92, Adults:65 – 80, Women:70 – 80, Men:65 - 70
From a normal of 70, the pulse of a person after a 100 meter dash might be about 120.
Less than 50 is said to be “bradycardia”. More than 110 is said to be “tachycardia”.