Download Cardiovascular Fitness

Fitness Focus:
Cardiovascular Fitness
Cardiovascular fitness is the body’s ability to continuously provide oxygen to the muscles while exercise is being
performed over a long period of time. Cardiovascular fitness includes the circulatory system and the respiratory
system. The circulatory system includes the heart, blood, and blood vessels. The respiratory system includes the
lungs and air passages. Both systems will improve drastically with exercise; however, both systems will also
become less efficient with lack of exercise or laziness. No matter how strong you might look, if your circulatory
and respiratory systems cannot meet your muscles’ demand for oxygen, you cannot continue physical activity for a
long period of time.
Oxygen is required for all cells of the body to live. We cannot live without oxygen more than a few minutes.
People often take oxygen for granted and never think of it as a fuel for the body. The fact is, the more oxygen
your muscles receive, the more energy they can produce and the longer you can exercise without tiring.
Blood vessels – includes the arteries, veins, and capillaries. Arteries carry blood with oxygen to the body’s cells,
while veins carry blood without oxygen back to the heart and lungs. Capillaries are the small vessels that connect
arteries to veins. A person has 60,000 miles of blood vessels in their body that reaches trillions of living cells.
Why do some people have lower resting heart rates than others? Slow heart = Strong Body! Ever hit a nail
with a hammer? A strong arm is a great advantage because you have to hit the nail only once or twice to drive it
into the wood. In contrast, a weak arm has to hit the nail five to six times before it is driven in wood, which will
cause the arm to tire out more easily. Therefore a strong arm is more efficient than a weak arm. The same
analogy is true for a strong heart! When your heart is strong and efficient, it has what is called a high stroke
volume. Stroke volume is the amount of blood pumped by the heart with each beat. The more blood you pump with
each beat, the more oxygen and nutrients the cells and muscles of your body will receive. If you have a high
stroke volume, your heart is efficient and your resting heart rate will be ideal and low. Therefore, a person can
measure their stroke volume by their resting heart rate. If your resting heart rate increases, your stroke volume
has increased! Likewise, if your resting heart rate increases, your stroke volume will have decreased! The stroke
volume of an average person is 70-80 ml per beat. The average heart pumps 5.5 liters of blood each minute. Also,
it takes one minute for a drop of blood to go through the whole blood circulation pathway of the body.
Why do some of your classmates breathe hard when they are exercising and some do not? It is not because
your lungs cannot handle the exercise. Lungs take in plenty of oxygen to complete most tasks, no matter how
strenuous the exercise. The problem is getting that oxygen to the muscles and that is the job of the heart! As
we learned previously, blood carries oxygen through the body, but a weak heart with a low stroke volume pumps
less blood insufficiently. The body has to have oxygen; because of this your body reacts and causes you to
breathe more rapidly and harder in order to receive more oxygen for the cells and muscles. Therefore, some of
your classmates breathe more heavily when they run around the track because they have a lower stroke volume
and low aerobic capacity.
How do I increase my stroke volume and aerobic capacity?
The heart is a muscle, therefore with continuous aerobic exercise, it will get bigger, stronger, and more efficient.
Just like your biceps muscle, if you do continuous dumbbell curls they will grow larger and more powerful. Your
heart is no different! When your heart becomes more powerful and efficient, it will pump out more blood with
each beat it takes. It is recommended that in order to increase your stroke volume and aerobic capacity, an
individual must be working in their target heart rate zone for 15 – 30 minutes of continuous aerobic activity.
CA State Standard: 4.2 Identify physical activities that are effective in improving each of the health-related physical fitness components.
Name __________________________________________ Period ______
Cardiovascular Fitness – 7th grade
Directions: Use the article to answer the questions below. The answers must be in your own words to show
understanding, not just a word for word recitation of what you read. If you cannot answer a question from
lack of information, use the internet or a dictionary to help. Answers must be in complete sentences.
1. What exactly is cardiovascular fitness?
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2. How does oxygen help your muscles?
Be specific.
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3. Why do some people have a lower resting heart rate than
others?
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4. Why do some people breathe harder than others when
exercising?
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5. How can you increase your aerobic capacity?
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6. What are some physical activities that will improve your
cardiovascular fitness? Name at least four.
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7. What is a physical activity that you enjoy that would increase
your cardiovascular fitness?
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4.2 Identify physical activities that are effective in improving each of the health-related physical fitness
components.