Heart and Breathing Rates with Physical Exertion

Fall 2010

Heart and breathing rates with physical exertion

What are your heart and lungs doing? Why? How do they work? These are some of the things we’ll be investigating in this unit

LABORATORY EXERCISE PROCEDURE

NOTE: If you are physically unable to perform the step exercise,substitute another mode of exertion which is measurable. Or let another person do the step test

During this Lab you will learn:

How to apply the scientific method
What an EKG is and what it means
How exercise affects heart rate and lung function
How to collect data using instruments
How to graph and interpret those data

Exercise and heart function

You have noticed (observation) that your heart rate seems to race when you physically exert yourself. You wonder if the human heart rate increases as the intensity of exercise increases. You can hypothesize that this is indeed the case. Same for lung volume and breathing rate. In addition to physical exertion, there are other things that affect heart rate and breathing, such as stimulants, alcohol, mood etc.

A.State an observation.

B. What problem or question has been identified?

C. The hypothesis is:

D. Experimentation:

To obtain the necessary data, you must determine your heart rate and respiration rate/lung volume (measured using a pressure sensor) at varying levels of physical exertion. You will first monitor your heart rate and respiration rate (and volume) at rest to establish a base line.**Note that lung volume will be measured using pressure to approximate volume. Why?

You will also be measuring your EKG. You’ll use this in other labs too.

Choose a partner – do this in groups of two.
Get a stethoscope (for heart rate)
Plug in your Vernier data collector (two of them: EKG and Lung volume).
Get a step stool near-by.
Carefully apply the Lung Volume monitor following the lab instructions
Carefully apply the EKG monitor following the lab instructions *Note: use tape to affix the EKG sensors
Resting heart rate: Sit quietly for at least five minutes,close your eyes and think of calm things…then determine your heart rate by having your partner use the stethoscope, count the number of heart beats in 15 seconds and multiply the number by 4 for heart beats/minute. On your report sheet, record your resting pulse rate in beats per minute. Take your pulse rate 3 times, so you have 3 measurements. Why?.
Record (on the computer) your lung volume and respiration rate (get a good graph for these and save it to a word file).
EKG: try several times until you can get a good ‘clean’ EKG.
Repeat the above in a reclined position (lie on your back). Any difference?

Now – step up the pace! NOTER: ideally you would do at least three trials. Why?

The stepexercise will be used at varying levels of intensity. In this exercise you will step up one step, then step back down the required number of times.
First trial: 20 steps in one minute. (Once every 3 seconds.) Look at your heart rate and write it down.
Record your lung pressure/rate, and EKG. Copy the graphs into your word document. Also, write down the data point in the table to the left of the graphs. Rest until your pulse rate nears your resting rate again. Mark down how much time it took your pulse to return to resting.
Second trial: 30 steps in one minute.
Record your heart rate, lung pressure/rate, and EKG. Record them.Copy the graphs into your word document. Also, write down the data point in the table to the left of the graphs. Rest until your pulse rate nears your resting rate again. Mark down how much time it took your pulse to return to resting.
Third trial: 60 steps in one minute
Record your heart rate, lung pressure/rate, and EKG. Record them.Copy the graphs into your word document. Also, write down the data point in the table to the left of the graphs. Rest until your pulse rate nears your resting rate again. Mark down how much time it took your pulse to return to resting.

E. Conclusions and results

Enter your data into an excel spreadsheet on the computer.
Graph your heart rate data, lung volume data, and breathing rate.
Also, note how long it took your heart rate to return to near resting heart rate after each trial.

1. Interpret the graph in your own words. What does it tell you?

2. Can we also conclude that:

The heart rate is directly proportional to the intensity of physical exertion? Why or why not? How about lung volume? Breathing rate?
That if we run this experiment on another family member the results and conclusion will besimilar? Why or why not?
That the graph for a highly conditioned athlete would look similar to your graph?Why or why not?

3. Could this test be repeated exactly by another researcher?Why is repeatability of experimentation important?

4. Is this test valid/reliable? Why or why not?

5. Design a better experiment that will yield results that are more reliable. What would you change?