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The Effect of Exercise on Heart Rate,
Breathing Rate, & Lung Capacity
Name _______________________________
Period ______ Date _________ Row # ____
When you exercise, your heart rate and breathing rate increase to provide your cells
with more oxygen and nutrients and rid your body of excess carbon dioxide.
Heart rate is a measure of the number of times that the heart beats in a minute. As the
heart pumps blood into arteries, vibrations result from the force of the blood moving
through these blood vessels. These vibrations can be felt at several arteries including
the carotid artery in your neck and the brachial artery in your wrist. An individual's
heartbeat is constantly changing in response to the metabolic requirements of the
body or changes in the environment that cause or alleviate stress. These changes in
heart rate are not within the conscious control of the individual. Changes in the heartbeat are controlled by
the autonomic nervous system, specifically the cardiac control center in the medulla oblongata. In times of
stress or exercise, the cardiac control center uses sympathetic nerve signals to increase heart rate and the
force of ventricular contraction. Stress hormones from the adrenal glands (epinephrine and norepinephrine)
also increase heart rate and force of heart contraction. In restful conditions, such as during a nap, when the
body requires less blood delivered to muscles, the cardiac control center uses parasympathetic nerves to
decrease heart rate.
Breathing rate is a measure of the number of times that you inhale and exhale. The rate increases during
exercise because the muscles require an increased supply of oxygen and nutrients. At the same time, very
active muscles produces a greater volume of carbon dioxide, a waste gas that must be removed by the lungs
via the blood. The regulation of breathing rate is under both voluntary and involuntary control, although a
person can only forcibly stop breathing for a limited amount of time. The regulatory system includes the use
of chemoreceptors, which can detect levels of carbon dioxide in the blood. High concentrations of carbon
dioxide occurring during exercise stimulate a fast breathing rate.
The amount of air that you move in and out of your lungs depends on how quickly you
are breathing. The amount of air that is moved in and out of the lungs when a person
is breathing is called the tidal volume. This amount of air provides enough oxygen for
the body when the person is resting. It is possible to inhale more deeply and exhale
more forcefully than usual. The maximum amount of air moved in and out of the lungs
when the deepest possible inspiration is followed by the strongest possible expiration is
called the vital capacity.
In this lab, you will determine your resting heart rate, heart rate after exercise, resting
breathing rate, breathing rate after exercise, resting tidal volume and vital capacity of
your lungs, and tidal volume and vital capacity after exercise.
Pre-lab Questions:
1. Why does your heart rate and breathing rate increase during exercise? ______________________________
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2. What is tidal volume? ____________________________________________________________________
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Procedures:
Measuring Heart Rate—Take your pulse for 30 seconds and multiply times 2 to get your pulse for one minute.
Record in data table. Repeat three times and find the average heart rate.
Measuring Breathing Rate—Have your partner count the number of breaths that you take in 30 seconds.
Multiply times 2 to get your breathing rate. Record in data table. Repeat
three times and find the average breathing rate.
Measuring Tidal Volume —
1. Stretch the balloon to make it easier to fill.
2. Breath normally a number of times. Take a normal breath and exhale a
normal amount of air into the balloon. Hold the end of the balloon shut
to stop the air from escaping. Measure the balloon’s diameter in
centimeters with the metric ruler and record as Tidal Volume in data
table. Repeat three times and calculate the average Tidal Volume.
3. Use the following formula to calculate the volume of air in the balloon.
Volume = 1.33π r3
where r = the radius of the balloon (1/2 of the diameter)
and π = 3.14
Effects of Exercise—
1. Vigorously exercise for 2 minutes (jumping jacks, running stairs, etc).
2. Record your heart rate, breathing rate, and tidal volume immediately after the exercise period is completed.
3. Repeat three times and calculate averages.
Data tables
Measuring Heart Rate
Resting Heart Rate
Trial 1
Heart Rate after Exercise
Trial 1
Trial 2
Trial 2
Trial 3
Trial 4
Trial 3
Trial 4
Average
Average
Measuring Breathing Rate
Resting Breathing Rate
Trial 1
Breathing Rate after Exercise
Trial 1
Trial 2
Trial 2
Trial 3
Trial 4
Trial 3
Trial 4
Average
Average
Measuring Tidal Volume
Resting Tidal Volume
Balloon diameter
measurement (cm)
Trial
Tidal Volume
1
Tidal Volume after Exercise
Balloon diameter
measurement (cm)
Trial
Tidal Volume
1
2
3
4
2
3
4
Average diameter
Average diameter
Average radius
Volume (cm3)
3
Volume = 1.33π r
Average radius
Volume (cm3)
Space for Notes/Calculations—
Analysis and Conclusions:
1. Why did you repeat each experiment 4 times? Why is this important? ______________________________
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2. Suppose the amount of blood pumped by your left ventricle each time it contracts is 70 mL. Calculate your
cardiac output (70mL x heart rate per minute) while at rest and just after exercise. (Show your work.)
Cardiac Output per beat
Average Heart Rate
Cardiac Output per minute
At rest
After exercise
3. Calculate the volume of air that enters your lungs every minute (average breathing rate x tidal volume) while
at rest and just after exercise. (Show your work.)
Average Breathing Rate
Tidal Volume
Lung Volume per minute
At rest
After exercise
4. How does vigorous exercise affect your heart rate and breathing rate? Why does your body respond this
way? __________________________________________________________________________________
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