# Investigation of the Cardiovascular System

## Investigation of the Cardiovascular System

• Submitted By: nun10
• Date Submitted: 05/19/2011 4:22 PM
• Category: Science
• Words: 1363
• Page: 6
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INVESTIGATION OF THE CARDIOVASCULAR SYSTEM
Introduction:
Aim: to investigate the effect of different age on heart rate.
Hypothesis: As age increases the heart rate decreases.
Independent variables: Age of subject
Dependent variables: Heart rate (bpm)
Controlled variables: Method of taking subjects’ heart rate
Materials:
• Stethoscope
• Stop watch
• Pencil and paper to record
Procedure:
• Select 30 subjects from different age group (10-19, 20-29, 30-39, 40-49, 50-59)
• Using a stethoscope and placing to the left of the sternum
• When the beats can be heard clearly, count them for 15 seconds using stop watch and record it
• Multiply the heart HR by 4 to calculate beats per minute (BPM)
Results: THE EFFECT OF AGE ON AVERAGE HEART RATE
Age group Heart rate Per minute
1 2 3 4 5 Average
10-19 80 72 68 72 80 74.4
20-29 80 76 68 52 56 66.4
30-39 60 56 68 68 66 63.6
40-49 84 64 60 72 64 68.8
50-59 64 64 60 52 68 61.6

Age interval of 1 represents 10-19 age group.
Age interval of 2 represents 20-29 age group.
Age interval of 3 represents 30-39 age group.
Age interval of 4 represents 40-49 age group.
Age interval of 5 represents 50-59 age group.

Discussion:
According to the data, the average heart rate of 10-19 age intervals is 74.4 bpm, 20-29 is 66.4 bpm, 30-39 bpm is 63.6 and the average heart rate of 40-49 age interval is 68.8 bpm. The effect of age on average heart rate graph is negatively correlated which demonstrate the fact that heart rate is dependable on age, as the age increase the heart rate decrease. This is because as age increase the heart muscle becomes less efficient at pumping blood around the body, the walls of the heart becomes more rigid, and it takes longer for the heart to fill with blood. It also takes longer for the heart rate to increase in response to any increase in physical activity (My Doctor, UBM Australia).

The procedure of the experiment was altered after measuring a few subjects’...