Be sure to have completed the pre-lab questions before proceeding.

MATERIALS

  • Bowl or pan deep enough to submerge the front part of the face
  • Water
  • Ice cubes
  • Pulse oxygen meter (available from NEAq TRC) OR stopwatch/stopwatch app/watch or clock
    with second hand
  • Students can also use their own FitBit if equipped with a heart rate display
  • Towel

Optional:Nail polish remover or acetone (The pulse oximeter may not work if there is nail polish on the nail)

Safety Note:

While this is a very safe lab to conduct in the classroom, students with a moderate to severe respiratory medical condition, seizure disorder, or other serious medical condition should avoid submerging their heads in the water without prior authorization from a medical professional. In addition, anyone under

a doctor’s care for a communicable disease should not share the same container of water with anyone else. Students should be encouraged to stop holding their breath at any time they feel dizzy or generally uncomfortable. Data can still be collected if the students fall short of the indicated

time frame.

LAB PROCEDURE

(Adapted from Santa Cruz-Watsonville Inquiry-Based Learning in Environmental Sciences and PBS NOVA Coma)

Read all the directions in Part A before proceeding.

B. Measure your resting heart rate.

  1. Sit normally in a chair.
  2. Take a few deep breaths to relax and then measure your resting heart rate according to the directions (Option A or B) below.
  3. Record your results in Data Table 1 on your Student Sheet.
  4. Repeat steps 1-4 for a total of three trials.
  5. Calculate the mean resting heart rate and record in Data Table 1.

Option A: Counting with a Stopwatch

  1. Place your index and third fingers on your partner’s neck to the side of your windpipe. (To check the pulse at the wrist, place two fingers between the bone and the tendon over the radial artery, which is located on the thumb side of the wrist.)
  2. When you feel the pulse, count the number of beats in 15 seconds. Multiply this number by 4 to calculate your beats a minute. (Laskowski)
  3. Repeat this procedure twice to insure accuracy. If the second resting heart rate is drastically different, repeat a third time. You can always average the three numbers if you have slight differences. Repeat until you have consistent measurements.
  4. Record your results in the data table.

Option B: Using a Pulse Oximeter

  1. Place the pulse oximeter on your fore, middle, or ring finger. Keep in mind that nail polish may impact the accuracy of the meter or prevent it from working.
  2. Record the resting heart rate.
  3. Repeat this procedure twice to ensure accuracy. If the second resting heart rate is drastically different, repeat a third time. You can always average the three numbers if you have slight differences. Repeat until you have consistent readings.
  4. Record your results in the data table.
  5. If you are using the pulse oximeter method, make a data table that also measures your oxygen saturation.

Read all the directions in Part B before proceeding.

B. Measure your heart rate while holding your breath.

  1. Sit normally in a chair.
  2. You will be holding your breath in the next step for either 15 or 30 seconds depending on your comfort level. Tell your partner to set the timer accordingly.
  3. Take a deep breath, close your eyes, and hold your breath. Remember you should breathe at anytime if you cannot make it the full duration.
  4. Your partner should record your heart rate 1 second before the timer is to go off. This is important because you do not want to measure the heart rate as you take your first breath.
  5. Once you hear the timer sound, you can breathe normally and open your eyes.
  6. Record your data in Data Table 2.
  7. If you are using the pulse oximeter method, make a data table that also measures your oxygen saturation.

Read all the directions before proceeding.

C. Measuring the Dive Response

  1. Fill a deep pan with cold water (approximately 15 degrees Celsius) (Add ice cubes if available). Make sure there is enough water that will allow your face to be submerged to
    the hairline.
  2. Sit down at a table.
  3. Have your partner set a timer for 15 or 30 seconds depending on your comfort level.
  4. Take a deep breath and hold it. Your partner will start the timer.
  5. Immediately lower your face into the water bath. Be careful not to get water in your ears.
  6. Your partner should record your heart rate 1 second before the timer is to go off. This is important because you do not want to measure the heart rate as you take your first breath.
  7. Once the timer goes off, lift your head out of the water and breathe normally.
  8. Use the towel to dry off.

9. Record your data in Data Table 2.

10. If you are using the pulse oximeter method, make a data table that also measures your
oxygen saturation.

D. Collecting Data

  1. Make a copy of data tables 3 and 4 on a central location so that all members of the class can access the information. This can be a shared digital file or on a white board.
  2. Copy the class data into tables 3 and 4.

E. Analyzing Data

  1. Calculate the mean for each numerical data column in tables 3 and 4. This can be done using a data analysis program such as MS Excel or equivalent.
  2. Follow your teacher’s instructions on further data analysis if applicable.

F. Conclusions

  1. Answer the post-lab questions.