This document describes a student's investigation into how exercise affects heart rate. The student formulated a hypothesis that exercise would increase heart rate and recovery would take no more than three minutes. The experiment measured heart rate at rest, after exercise, and during an 11 minute recovery period. The results showed that exercise increased heart rate for all subjects and that full recovery took 11 minutes, longer than the student originally predicted. The student concluded that the heart rate takes significant time to recover from exercise.

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 effect of exercise on
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Investigating the
heart rate
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Giacomo Cetta
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Giacomo Cetta
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2. Design
Research Question
The research question of our biology class practical is: how does exercise affect the
intensity of the heart beat? This question will help us during the investigation stage and
the practical part of our experiment. The heart, pumps blood to all the body, we need
blood because it carries oxygen to all the parts of the body. But what happens to the heart
when we do exercise? To find this out, we will measure our heart rate at rest, and then
after doing exercise, we will also measure the time that our heart takes to go back to its
original rate.
Hypothesis
I have an idea of what will happen to our heart beat after the exercise. I think that our
heart rate will increase, so if at rest we do 69 beats per minute, on exercise we will do 110
beats. This is because the demand of oxygen from our body, increases since we will need
more oxygen to make our body work under exercise, and this oxygen will be pumped by
the heart to the body by arteries. To recover instead, it will not take a lot because as soon
as you stop exercising, we spend one minute taking deep breaths that gives us a lot of
spare oxygen that makes us recover in not more than three minutes.
Equipment
Chronometer (for keeping time of the duration of the exercise)
Pen and paper (for writing the data)
Calculator (for measuring the heart rate change)
Variables
To make this experiment a “fair experiment”, we have to count all the dependent
variables, independent variables and all the controlled variables. The dependent variables
are the variables that we measure, which are the change in heart rate (resting and
exercise), and the speed of recovery (after exercise). The independent variables are the
variables that we change, so we have to count if people exercise more than five hours a
week or less. If people exercise more than five hours, their heart is more trained to do
exercise, so their heart beat will be less frequent and their speed of recovery will be faster.
The last, are the controlled variables. These variables make the test fair and they are
variables that we control. For our experiment, our controlled variables are: the same
distance and age, the same type of activity, and the same gender.
Method
The first thing I need to do with my group is to draw a rough table on which I can write the
results. Then we had to decide what exercise we will do for the experiment on the heart
beat. We decided to: go up and down parts of the stairs for ten times. Done that, we can

3. start to fill our table with our heart rate at rest; We measure how many heart beats we
have in one minute.
Then with my group we can start doing the actual practical. As soon as it ends we carefully
measure our heart rate, even in this case the time that we measure the beats of the heart
is one minute. Then for measuring the recovery time, we all sit down so we are sure that
we don’t move any more and our body completely rests. To be sure that we completely
recover, we measure our heart beat every minute for eleven minutes.
The last part of the practical will be to measure the heart rate change, which is measured
by taking away the at rest heart rate from the after exercise heart rate.
Analysis
Valentina David Giacomo Beatrice
At Rest 66 60 72 84
After Exercise 96 120 150 168
+1 minute 87 112 146 163
+2 minute 81 104 139 154
+3 minute 74 97 132 147
+4 minute 69 91 126 141
+5 minute 65 83 119 135
+6 minutes 65 77 111 129
+7 minutes 65 69 97 116
+8 minutes 64 62 93 108
+9 minutes 65 60 84 95
+10 minutes 65 60 78 89
+11 minutes 65 60 70 83
H. R. Change 96-66=30 120-60=78 150-72=78 168-84=84

4. Heart Beat Graph
180
160
140
120
100
80 Valentina
60 David
40 Giacomo
20 Beatrice
0
Conclusion
The first thing to say is that my hypothesis was partially wrong, since I said that after
exercise the heart beat would increase and it did. But I said that in no more than three
minutes we would had recover our original heart beat instead it took eleven minutes. So I
learned that the heart rate takes a lot of time to recover from an exercise.
Evaluation
I think my method worked very well since the results of the practical were possible as
results. We also made sure that the recovery part was the same for every one since we
were all sitting down. We also counted all the possible variables, so I think that we couldn’t
had improved it in anyway. Maybe the only weakness was the keeping the count of the
heart beat that we did by ourselves by placing our finger on our chest or on our wrist or on
our neck, here, maybe someone didn’t feel the exact number of beats.