Heart Rate: Position & Exercise*

Teacher Version(.doc)

Student Version(.doc)

• Grade Level(s): 7th
• Primary Focus: Science; NC Standard Course of Study Areas: 7th 4.01, 4.04, 4.08
  • (Key concepts:  Human body systems, regulation of internal environment, health)
• Secondary Focus: Math; NC Standard Course of Study Areas: 7th 1.03, 4.01, 4.02, 4.03, 4.04
  • (Key concepts:  Flexible problem solving, averages, graphs, addition, subtraction, multiplication, and division)
• Computer/Technology Skills: Calculators, Probeware, Data Visualization; NC Standard Course of Study Areas: 7th 1.10, 2.02, 3.01, 3.02, 3.05
• Essential Question: How does your body position affect your resting heart rate? How does your heart rate change when you exercise, then rest?
• Summary of Activity:  Students will measure their heart rate while standing, sitting, lying down and exercising.
• Cognitive Teaching Strategies: Students will make predictions as to how body position affects their heart rate. In addition, they will investigate the effect of exercise on heart rate and how this varies between students.
• Materials:
  • TI-84 Plus Silver graphing calculator
  • EasyData application
  • EasyLink interface
  • Vernier Hand-Grip Heart Rate Monitor
  • chair
  • stepping stool, 40 cm high
  • timer
  

Part I: Body Position

1. Turn on the calculator. Connect the receiver module of the Heart Rate Monitor, data-collection interface, and calculator.
   Set up EasyData for data collection.
2. Start the EasyData application, if it is not already running.
   1. Select  from the Main screen, and then select New to reset the application.
   2. Select  from the Main screen, then select Time Graph…
   3. Select  on the Time Graph Settings screen.
   4. Enter 10 as the time between samples in seconds.
   5. Select .
   6. Enter 72 as the number of samples and select . Data collection will last 720 seconds (12 minutes).
   7. Select  to return to the Main screen.
3. Set up the Hand Grip Heart Rate Monitor.
   1. Sit in a chair, facing away from the calculator and your classmates. Grasp the handles of the Hand-Grip Heart Rate Monitor your hands. The fingertips of each hand should be placed on the reference areas of the handles. The left hand grip and the receiver are both marked with an alignment arrow. When collecting data, be sure that the arrow labels on each of these devices are in alignment (see Figure 1). The reception range of the plug-in receiver is 80−100 cm, or about 3 feet.
   2. Monitor the live readouts on the calculator screen to determine that the sensor is functioning correctly. There will be a 10–15 second delay while data are collected before the first heart rate is reported. The readings should be consistent and within the normal range of the individual, usually between 55 and 90 beats per minute.
   3. If the readings appear unreasonable, reposition your fingers and check the sensor and receiver alignment.
   4. Once it is apparent that the sensor is functioning correctly, continue with Step 4.

Sitting Heart Rate

1. Once the subject has been seated quietly for about a minute, a partner should select  to begin monitoring heart rate. Another partner should begin timing at the same time.
2. Determine the subject’s sitting heart rate.
   1. Select , and then select Statistics…  11/14/2006/3 of the graph (up to about 240 seconds) that matches with the sitting part of the experiment.
   2. Use  to move the cursor to the beginning of this flattest part and then select .
   3. Move the cursor to the end of the flat part and select .
   4. Record the mean (average) heart rate (to the nearest whole bpm) on your data sheet. This is the subject’s sitting heart rate.
   5. Select  to return to the graph.

Reclining Heart Rate

1. After 4 minutes of data collection have gone by, the subject should recline on a clean surface, floor or table and facing away from all classmates. Note: A partner should tell the subject when it is time to recline.
2. Determine the subject’s reclining heart rate.
   1. Select , and then select Statistics…
   2. Note the flattest part of the middle 1/3 of the graph (from about 240 seconds up to about 480 seconds) that matches with the reclining part of the experiment.
   3. Use  to move the cursor to the beginning of this flattest part and select .
   4. Move the cursor to end of this flat part and select .
   5. Record the mean (average) heart rate (to the nearest whole bpm) on your data sheet. This is the subject’s reclining heart rate.
   6. Select  to return to the graph.

Standing Heart Rate

1. After 8 minutes of data collection have gone by, the subject should stand facing away from all classmates. A partner should again tell the subject when it is time to stand. Data collection will automatically stop after 12 minutes (720 seconds).
2. Determine the subject’s standing heart rate.
   1. Select , and then select Statistics…
   2. Note the flattest part of the last 1/3 of the graph (from about 480 seconds up to 720 seconds) that matches with the standing part of the experiment.
   3. Use  to move the cursor to the beginning of this flattest part and select .
   4. Move the cursor to end of this flat part and select .
   5. Record the mean (average) heart rate (to the nearest whole bpm) on your data sheet. This is the subject’s standing heart rate.
   6. Select  to return to the graph.

Reviewing Data

1. Examine the graph that is displayed after data collection ends. You should be able to recognize three parts that match with the subject’s sitting, reclining, and standing heart rates.
2. Repeat Steps 1-9 with another member of the team if time allows.

Part II: Exercise

1. Set up EasyData for a new data collection set.
   1. Start the EasyData application, if it is not already running.
   2. Select  from the Main screen, and then select New to reset the application.
   3. Select  from the Main screen, then select Time Graph…
   4. Select  on the Time Graph Settings screen.
   5. Enter 5 as the time between samples in seconds.
   6. Select .
   7. Enter 80 as the number of samples and select . Data collection will last 400 seconds (12 minutes).
   8. Select  to return to the Main screen.

Standing Heart Rate

Once the subject has been standing quietly for about a minute, a partner should select  to begin monitoring heart rate. Another partner should begin timing at the same time. The subject should stand quietly for 100 seconds.

Step Test

1. When 100 seconds have gone by, immediately begin to exercise as follows:
   1. Place your right foot on the top step of the stool.
   2. Place your left foot completely on the top step of the stool next to your right foot.
   3. Place your right foot back on the floor.
   4. Place your left foot completely on the floor next to your right foot.
   5. Each stepping cycle should take 3 seconds to complete.
   6. Continue the step test for a total of 100 seconds.
   7. (Note: The student can jog slowly in place if there are not enough stools)

Recovery Time:

1. After 100 seconds of stepping (a total of exactly 200 seconds of data collection), stop stepping. Stand quietly for 200 seconds. Data collection will end automatically.

Analyzing the Data:

1. Examine the graph that is displayed after data collection ends. You should be able to recognize three parts of the graph that match with standing, exercising, and recovery time.
2. Determine the subject’s standing heart rate.
   1. Select , and then select Statistics…  
   2. Note the flattest part of the first 1/4 of the graph (up to about 100 seconds) that matches with the standing part of the experiment.
   3. Use  to move the cursor to the beginning of this flattest part and then select .
   4. Move the cursor to the end of the flat part and select .
   5. Record the mean (average) heart rate (to the nearest whole bpm) on your data sheet. This is the subject’s standing heart rate.
   6. Select  to return to the graph.
3. Determine the subject’s maximum heart rate.
   1. Use  to move the cursor to the highest point on the graph.
   2. Record the time (in s) and the heart rate (to the nearest whole bpm) for this point on your data sheet.
4. Determine the time when the subject’s standing heart rate returned to within 3 bpm of the standing rate.
   1. Starting at the highest point on the graph, use  to move the cursor to the right.
   2. Stop where the displayed heart rate first reads within 3 bpm of the standing heart rate value.
   3. Record the time for this point on your data sheet.
5. Sketch or print the graph as directed by your teacher.
6. Repeat Part II with other members of the team serving as subjects.

Instructional Strategies:

1. Groups of three students work well for this lab. One student is the experimental subject, one holds the sensor in the correct orientation and distance from the heart rate hand grips, and the last student manages the calculator.
2. In order to get good results, it is important for the sensor to be held a constant distance and correct orientation. Also, talking, laughing, moving, etc. will affect the heart rate.
3. Make sure none of your students have medical conditions that would preclude them from participating in the lab.

Additional Resources for this Lesson:

1. Target Heart Rates (from American Heart Association) provides target and recommended maximum heart rates for different groups.
2. Heart Rate (from Wikipedia) provides additional background information and definitions of heart rate measures.
   

Re-teaching and Enrichment Strategies:

1. Imagine measuring your heart rate while standing on your head. Would you expect your heart rate to be higher or lower than standing, sitting or reclining? Why?
2. Survey your classmates to determine how much they exercise each week. Determine if there is a relationship between amount of exercise and recovery time for your class.

Data Collection and Analysis: Part I Body Position

HYPOTHESIS:

DATA:

Subject’s name
Sitting heart rate (beats/min)
Reclining heart rate (beats/min)
Standing heart rate (beats/min)
Difference between sitting and reclining heart rates (beats/min)
Difference between standing and sitting heart rates (beats/min)
Difference between standing and reclining heart rates (beats/min)

QUESTIONS:

1. In the space provided in the data table, subtract to calculate the difference between the sitting and reclining heart rates for each subject.
2. Subtract to find the difference between the standing and sitting heart rates for each subject.
3. Subtract to find the difference between the standing and reclining heart rates for each subject.
4. Does the position of your body affect your heart rate?
5. Compare your results with those of other students.
6. Try to explain the results of the experiment.

Data Collection and Analysis: Part II Excercise

HYPOTHESIS:

DATA:

Subject’s name
Standing heart rate (bpm)
Maximum heart rate (bpm)
Time at maximum heart rate (s)
Time at return to within 3 bpm of standing rate (s)
Recovery time in seconds (s)

QUESTIONS:

1. In the space provided in the data table, calculate the recovery time for each subject. (Subtract the time at maximum heart rate from the time when the rate returned to within 3 bpm of the standing rate.)
2. Compare the standing heart rates of the members of your group.
3. How does your maximum heart rate compare to other students in your group? Is this what you expected? How do you account for this?
4. How does your recovery time compare to other students in your group? Is this what you expected? How do you account for this?
5. Why would athletes need to work longer and harder before their heart rates were at the maximum value? Explain.

DISCUSSION:

How does your body position affect your resting heart rate? How does your heart rate change when you exercise, then rest?

*Adapted from: Volz, D., & Sapatka, S. (2000). Middle School Science with Calculators. Beaverton, OR: Vernier Software & Technology.