Does Gender Affect Exercising and Resting Pulse Rates in 7th Graders? 

Researched by Katlin T.


The purpose of this experiment was to determine the difference in exercising and resting heart rates of 7th grade boys vs. 7th grade girls. 

I became interested in this idea because I have been interested in the medical field as a possible career. I have always wondered if resting or exercising individuals would have a greater heart rate. 

The information gained from this experiment could benefit coaches, parents, and doctors so they know what to expect from 7th graders.


My first hypothesis was that the heart rate would be greater after exercising than resting.  I based this on observation of my own pulse during exercise.

My second hypothesis was that the heart rate for girls would be greater than the boys while resting. I based this on The World Book Encyclopedia which stated, “A person’ size largely determines a person’s resting heart rate. The bigger a person is, the slower the heart rate.” 

My third hypothesis was that after exercising the heart rate for girls would be about the same as the heart rate for boys. This was based on a passage in The World Book Encyclopedia that said,”… usually the average person’s heart rate is about the same, 72 beats per second.”


The constants in this study were: 
* Boys’ and girls’ ages (12-13 years)
* The room temperature
* The room and equipment
* The exercise type and exercising time
* The rest and the resting time
* The method of taking heart rate
* The time of taking the heart rate (15 seconds)

The first manipulated variable was whether the subject had rested or exercised.

The second manipulated variable was the gender of the subject.

The responding variable was the heart rate.

To measure the responding variable I took the pulse for 15 seconds.


15 boys
15 girls
2 step- up benches used for step aerobics
2 stopwatch
2 chair
1 metronome 


1. Obtain the subjects by having them get a signed parent permission slip.
2. Have one student at a time come to the testing location.
3. Have the subject rest in a chair for three minutes while the instructions are given.
4. Take the pulse of the subject on the left wrist for fifteen seconds and record on the data table.
5. Have the subject rest for two more minutes.
6. Check the pulse of the subject for fifteen seconds and record on the data table.
7. Now, have the subject exercise on an 8-inch step bench for three minutes at a tempo of 100, which would be 25 full step up/ step down motions using both feet per minute.
8. Check the pulse and record on the data table.
9. Have the subject exercise for three more minutes as in step 7.
10. Check the pulse and record on the data table.
11. Have the student return to class.


The original purpose of this experiment was to determine the difference in exercising and resting heart rates of 7th grade boys vs. 7th grade girls.

The results of the experiment were that the heart rate was greater after exercising than resting. I also found out that the heart rate for girls was greater than boys while resting. I finally found out that immediately after exercising the heart rate for girls was greater than boys.

See the table and graph below.



My first hypothesis was that the heart rate would be greater after exercising than resting. My first hypothesis was accepted because the average after resting was 189 and the average after exercising was 251.

My second hypothesis was that the heart rate for girls would be greater than the boys while resting. My second hypothesis was rejected because the girls average for resting was 189 and boys average for resting was 189.

My third hypothesis was that after exercising the heart rate for girls would be about the same as the heart rate for boys. My third hypothesis was accepted because after exercising the girls average was 253 and after exercising the boys average was 249.

Because of the results of this experiment, I wonder if the exercising and resting pulse rates would be different 7th graders and 3rd graders or 7th graders and 12th graders. 

If I were to conduct this project again I would have tested many more subjects. I also would have used an electric heart monitor to improve the pulse accuracy. 

Research Report
The heart is a hard working pump whose action sustains life. Each beat sends blood throughout the body to carry oxygen and food all over to the body’s cells. The beating of the heart begins seven months before birth. When the heart stops, we die.

The heart is a large hollow organ divided into the left and right sides that pump at the same times. The veins collect blood from the body and carry it to the right side of the heart. The ventricles pump the blood to the lungs, where it picks up oxygen. Then, the oxygenated blood flows to the left side of the heart, which pumps it through the arteries to the rest of the body. Valves control the flow of blood throughout the heart.

The division of the nervous system called the autonomic nervous system regulates the heart and blood vessels. This automatic system controls your body’s activities that are performed automatically without conscious control. The heart’s rate increases and decreases, depending on your body’s needs. The heart pumps slowly while a person is sleeping, providing small amounts of oxygen to the resting body. The heart can then speed up and increase oxygen supplies when the person exercises.

Various diseases can strike any part of the heart. Although the death rate has fallen, disorders of the heart and blood vessels remain the leading cause of death in the United States and many other countries. Most common heart diseases narrow arteries that supply the heart with blood and oxygen. The deposits and fatty materials gradually build up and block these arteries.

The heart lies between the lungs, about in the middle of the chest. People’s heart is a little larger than their fist. A newborn heart weighs about 2/3 of an ounce, which is approximately nineteen grams. An adult heart weighs from nine to eleven ounces. That is equal to about 255 to 312 grams.

A membrane called the epicardium covers the outside surface of the heart. The pericardium, another membrane, surrounds the epicardium. The pericardium encloses the heart completely. It also extends above the blood vessels that emerge from the top of the organ. A slimy liquid between the epicedium and the pericardium lubricates the heart and enables it to contract smoothly.

Circulatory System

On average, the body has about 5 liters of blood in the circulatory system. The heart, lungs, and blood vessels work together to form the circulatory system.
The body’s circulatory system has three parts: pulmonary circulation, coronary circulation, and systemic circulation. They are also known as the lungs (pulmonary), the heart (coronary), and the rest of the system (systemic). Each must work independently in order for them to work together.

The circulatory system is responsible for transporting materials throughout the body. It gives nutrients, water, and oxygen to the body’s cells and carries wastes away, such as carbon dioxide.


A stretching of the arteries that takes place after each heartbeat causes the pulse. It can be taken or felt by placing the fingers on their wrist above the thumb at a point over the radial artery. The other pulse can be felt by touching the temples where the temporal artery is located, and at other places in the body where an artery is near the surface.

Each heartbeat consists of a contraction of the muscles of the heart that propels the blood into the arterial system, followed by a period of time that is used for relaxation while the heart refills. As the heart contracts, the blood is pumped in to the aorta and pulmonary arteries. The aorta, which is the largest artery in the body, carries the blood aerated by the lungs. Its elastic walls are stretched and it expands to make room for the blood. As the blood moves on to enter the arteries that branch off from the aorta, the walls relax and it contracts to normal size. The walls of the arteries and of their branches also expand and contract as the blood passes through them. The expansion of these arteries causes the pulsation known as the pulse.

Pulse Rate

The pulse rate of children is faster that older people which is often slower than that of the average healthy adult. Pulse rates between 50 and 85 per minute are considered within normal limits. The normal rate for an average man is about 72, while women’s is 76-80. The pulse rate of a newborn child can be as high as 140 per minute. The normal rate for a seven- year- old is about 90. A slower pulse rate of 50 to 65 is not unusual in elderly people. Regardless of a person's age the pulse and heart rhythm should be regular.


A successful exercise involves frequent physical activity that is rhythmic, repetitive, and challenges the circulatory system, and uses your large muscles. Exercise must significantly increases the blood flow to the muscles for a certain amount of time promoting cardiovascular fitness, which is also known as iconic, dynamic, or aerobic fitness.

Aerobic activities get the blood pumping. As the heart beats faster, the blood circulates more quickly, giving more oxygen to our muscles.


Abel, Francis L “ Circulatory System.” The World Book Encyclopedia. 1998.

Avraham, Regina. The Circulatory System New York: Chelsea House Publishers, 1989. pp:1-110

Crawford, Michael H “Heart.” The World Book Encyclopedia. 1998.

Galperin, Anne. Strokes and Heart Diseases New York: Chelsea House, 1991. pp: 1-107

Silverstein, Alvin. The Circulatory System New York: Twenty First Century Books,1994. 1-96

Silverstein, Alvin.  The Respiratory System New York: Twenty First Century Books,1994. 1-94


I would like to thank the following people for helping make my project possible:
* My parents for helping me out through the year with transportation and much more.
* Human subjects for helping me in the experiment and doing my experiment.
* Teachers for letting their students come out of class to do the experiment.
* Mr. Newkirk and Mrs. Helms for helping me with everything! I really appreciated it.

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