# Heart Rate Lab

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• Published : December 20, 2012

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Design

Aspect 1: Defining the problem and selecting variables

In this lab, we will be studying the difference of heart rate between boys and girls. There are many things that can increase heart rate, such as exercise, drinking coffee, taking certain pills, drinking an energy drink, feeling a strong emotion, etc. I have chosen to use exercise as a means of increasing the heart rate of my subjects, more precisely, 20 sit-ups. There are many reasons why your heart rate increases when you exercise, the most important one being that your muscles require more oxygen and nutrients. For this requirement to be met the heart needs to pump more blood to the muscles, hence the heart rate increases.

Problem: Determining the difference, if there is any, in the change of heart rate between girls and boys after they have done 20 sit-ups.

Variables:
Independent Variable| Dependent Variable| Controlled Variables| Amount of sit-ups subjects do| The change in heart rate after subjects are done sit-ups| Rate at which subjects do sit-ups: did sit-ups to a metronome; 1 every 2 seconds.| Boys and Girls: comparing the heart rate change between boys and girls; need an equal amount of each gender.| | Quality of sit-up: I made sure they were doing their sit-ups properly (no resting/cheating)| | | Same Heart Rate Measurer for all subjects: accuracy might be less than good so this step makes sure the change in heart rate doesn’t change.|

Aspect 2: Controlling Variables

Apparatus:
* Mat (for sit-ups)
* hand grip heart rate monitor
* Vernier computer Interface
Procedure:
I. Get the equipment ready and place the mat on the floor. II. Record the heart rate of the subject at rest (BEFORE the sit-ups) with the hand grip heart rate monitor and Vernier computer interface. III. Save the data and get the subject ready for sit-ups. Turn on the metronome and set it at 60 beat/minute. IV. Make the subject do 20 sit-ups at a constant pace, once per 2 beats. Make sure the subject is doing the sit-ups properly. V. Once the sit-ups are done, record her heart rate with the hand grip heart rate monitor and the Vernier computer interface. Try to measure it as soon as possible as the exercise is not demanding for many people and the heart rate could quickly drop. VI. Repeat same steps for all subjects.

Aspect 3: Developing a method for collection of data

For the results to be accurate, we need more than one subject per gender. Since there are only 2 variations of an independent variable, we will test each one 10 times (10 girls, 10 boys).

Data Collection and Processing

Aspect 1: Recording raw data

Raw Data:

Trials| Heart Rate before sit-ups (±1)| Heart Rate after sit-ups(±1)| Boy #1| 70| 126|
Boy #2| 83| 111|
Boy #3| 92| 121|
Boy #4| 82| 95|
Boy #5| 96| 115|
Boy #6| 93| 115|
Boy #7| 80| 107|
Boy #8| 81| 98|
Boy #9| 72| 121|
Boy #10| 94| 127|
Girl #1| 82| 118|
Girl #2| 101| 125|
Girl #3| 70| 90|
Girl #4| 72| 93|
Girl #5| 81| 110|
Girl #6| 90| 116|
Girl #7| 98| 129|
Girl #8| 95| 122|
Girl #9| 94| 119|
Girl #10| 76| 95|

Aspect 2: Processing raw data

Trials| Percentage Difference In Heart Rate before and after sit-ups (%) (±2)| Average of Percentage differences In Heart Rate before and after sit-ups by gender(%)(±20)| Boy #1| 80.0| 36.3|

Boy #2| 33.7| |
Boy #3| 31.5| |
Boy #4| 15.9| |
Boy #5| 19.8| |
Boy #6| 23.7| |
Boy #7| 33.8| |
Boy #8| 21.0| |
Boy #9| 68.1| |
Boy #10| 35.1| |
Girl #1| 43.9| 30.2|
Girl #2| 23.8| |
Girl #3| 28.6| |
Girl #4| 29.2| |
Girl #5| 35.8| |
Girl #6| 28.9| |
Girl #7| 31.6| |
Girl #8| 28.4| |
Girl #9| 26.6| |
Girl #10| 25.0| |

Sample Calculations:

Percentage Difference In Heart Rate before and after sit-ups (%)

Formula: If x1= Heart Rate before...