The Power of Per

This lab asks students to examine the correlation of heart rate and breathing rate by collecting data under two different conditions: during rest and after exercising.

Students may need help locating the proper location on the wrist for taking a pulse. Students will also need to multiply their rate by 2 in order to have a unit rate (per minute).

Paraphrase:

Do you think breathing rate and heart rate correlate?

Today you will be exploring whether there is a relationship between your breathing and your pulse.

How can we measure breathing rate?

• For 30 seconds, count the number of breaths you take.
• How do we convert that to a breathing rate?

How can we measure heart rate?

• Using the method shown in the photograph, locate where you can feel your pulse. We'll all count the number of heartbeats in our own pulse for exactly 30 seconds.

How do we convert that to a heart rate?

STUDENT LAB WORKSHEET (alternatively students may record work in lab notebooks):

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The lab will be repeated for each member of the group by rotating roles.

Paraphrase:

You will need to work in groups of four for this lab. You will all get turns doing four different jobs:

1. Timekeeper
2. Breath counter
3. Pulse taker
4. Subject (the person being measured)

Decide who will take which job first.

Step 1. Decide who does what

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Remind students that they should take the resting pulse two times and find the average. Repeat this process for all members of the group by rotating roles.

(PDF above includes table to the right)

Step 2. Collect baseline data

Make a chart like this one in your lab notebook or on your device.

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Tell the subject to sit quietly for a few moments.

Measure resting heart rate: Using the method shown in the photograph, the pulse taker locates where he or she can feel the subject’s pulse. When the timekeeper signals, the pulse taker counts the number of heartbeats in exactly 30 seconds.

Measure resting breathing rate: During the same 30 seconds, the breath counter observes the subject and counts the number of breaths he or she takes. Record your data in the table on the next page.

Repeat this procedure so you can find an average for accuracy. Remember to convert your data to a unit rate (per minute) by multiplying by 2.

When you have finished collecting baseline data for the first subject, continue Step 1 by rotating jobs until everyone in your group has had their resting heart rate and resting breathing rate measured.

After all members have recorded their baseline data (the first three rows of the table), the group repeats the rotation; however this time they will exercise by jumping rope at both a low- and a high-intensity level. Because of the time involved, students do not need to conduct multiple trials. Make sure students convert to unit rates.

NOTE: Students who are unable to jump rope should be encouraged to elevate their heart rate in other ways depending on their abilities.

Step 3. Measure the effects of exercise

Now you are going to measure the effects of exercise at two intensity levels.

The procedure is exactly the same as Step 1, but this time the subjects will be exercising prior to data collection.

​Low-intensity testEach subject jumps rope (or a similar exercise) at a slow pace for one minute.Immediately after they complete this task, measure their pulse and breathing for 30 seconds. (Don’t forget to convert to a unit rate.) High-intensity testEach subject jumps rope (or a similar exercise) at a fast pace for two minutes.Immediately after they complete this task, measure their pulse and breathing for 30 seconds. (Don’t forget to convert to a unit rate.)

When you have finished the low- and high-intensity exercise tests for the first subject, rotate jobs and return to Step 2 so that everyone in your group is measured.

Step 4. Graph your data

After you complete your table, make a graph like this one in your lab notebook or on your device, then plot your data points on the graph. Use one color to represent heart rate and a different color to represent breathing rate.

Have students plot their data points on the graph.

If any of your students are unfamiliar with graphing, show them a sample graph on the chart.

Ask students to use two different colors—one for heart rate and one for breathing rate.

Some students may need an example of how to plot data on a graph. Encourage group members to assist each other with the graph.

(PDF above includes table to the right)

Remind students to use full sentences when writing their responses to the questions.

Have students discuss these questions with their group prior to writing their responses. You may want to ask them to agree on a response based on all of their data. Students may also complete this independently based on their own data.

Step 5. Analyze the data

Consider your data.... What might it mean?

1. What effect does exercise have on your breathing rate? On your pulse rate?
2. Is there a correlation between your breathing and pulse rates? If so, why do you think this relationship exists?
3. Why did you repeat your measurements when collecting baseline data? Would you have better data if you repeated the other tests too? Why or why not?
4. You have collected quantitative data about what happened when you exercised. Can you add some qualitative data about what happened during the tests? For example, did your face feel hot?
5. On a scale from 1 to 4, rate your group’s precision when collecting data

• disorganized and imprecise
• okay, but not great
• good with minor exceptions
• flawless

The groups report their findings one at a time. Take notes on their claims and look for patterns.

Using the data from all of the subjects, the group can make a claim based on this lab work. Remind students that a claim is something that they think is true and have data or evidence to support it.

Step 6. Share claims

Can your group make a claim about something you think is true based on the evidence in your lab work? If so, MAKE IT!

Claims can take a form like these:

• Exercise affects my heart rate by ____. Exercise also affects my breathing rate by ____.
• There is a correlation between ____. I think this relationship exists because ____.
• It is important to repeat measurements when collecting baseline data because ____. It is likely that ____ because ____.
• Some examples of qualitative data that occurred during the tests include ____ .