The Human Heart Rate

The Human Heart Rate

Aim: To study changes in the rate of the human heartbeat.

Introduction: Blood is sent pulsing through the body's veins, arteries and capillaries with each beat of the heart. The circulation of blood through the body delivers oxygen and food to the cells and removes wastes. The cells cannot survive if circulation stops for even a small amount of time. With an increase in body movement there is an increase in the cell's energy use and the heart rate must increase to pump enough blood to the cells. Then, as body movement decreases again, so does the heart rate. The heart muscle can be enlarged with regular vigorous exercise. A larger heart is more efficient than a smaller heart as it is stronger and can hold more blood. The heart is a cardiac muscle and contracts by itself, even when removed from the body. The muscles rhythmic beat is sped up or slowed down by the autonomic nerves that are attached to the heart. The heartbeat has two phases. Systole is the name given to the contraction phase and diastole is the name given to the relaxation phase. The heart valves slapping closed provides the sound of the heartbeat.

Materials

* Stopwatch

Procedure - Part A

1. The group sat quietly and relaxed for two minutes.

2. The stopwatch was used to time 30 seconds while the pulse of the members was taken. The pulses were then multiplied by two.

Part B

1. The group walked around the building for three minutes.

2. Step 2 of Part A was repeated.

Part C

1. The group took part in various forms of vigorous exercise including running, step-ups, running up the stairs and star jumps for three minutes.

2. Step 2 of Part A was repeated.

Results

Resting

Box Rate Box Rate

1 74 15 76

2 54 16 56

3 78 17 82

4 70 18 90

5 50 19 108

6 78 20 60

7 84 21 70

8 66 22 76

9 78 23 84

10 78 24 66

11 50 25 80

12 62 26 80

13 74 27 66

14 74 28 76

Mild Exercise

Box Rate Box Rate

1 94 15 110

2 84 16 78

3 98 17 100

4 90 18 98

5 72 19 102

6 84 20 76

7 76 21 86

8 88 22 94

9 94 23 106

10 102 24 72

11 84 25 92

12 90 26 102

13 88 27 68

14 94 28 86

Vigorous Exercise

Box Rate Box Rate

1 150 15 134

2 128 16 132

3 160 17 160

4 120 18 152

5 102 19 154

6 148 20 132

7 124 21 150

...