The Effect of Exercise on Heart Rate

I am investigating the effect that exercise has on a person\'s heart rate. The heart rate of a human varies from 150 beats per minute in young children, to about 60 in the elderly.

Apparatus being used: -
· Stopwatch – to measure accurately how long each exercise period goes on for.

· Exercise equipment – provided by the teacher.

· Exercise clothes worn by the person – trainers’ etc.

To make this a fair test I will be using the same person throughout the whole experiment. They will be doing the same type of exercise and will get equal rest’s in-between each intensity period. The person will be doing the same exercise for the same period of time. I will try and make sure the room temperature is roughly the same so that the hotter climate wouldn’t make the heart rate increase.

Prediction: -
I predict that the heart rate will increase as a result of exercise. I think that there will be a gradual increase to begin with and as the body begins to have to work harder the heart rate will increase at a faster rate. When the exercise is complete I think that the heart rate will gradually decrease back to the resting pulse rate.

I have made these predictions because I think that as the time increases the heart rate will increase as the supply of oxygen to the muscles will decrease therefore the heart has to work harder in order to get enough oxygen around the body to the cells. I also think that a lot of energy will be used up as the exercise takes place, this will make the heart push even harder, and if the body is unable to continue aerobic respiration then anaerobic respiration will take place. This results in lactic acid being formed, this makes the muscles feel tired and the muscles also feel tight or strained. Then finally the Carbon dioxide levels would rise which would contribute to the heart rate rising.

Method: -

· Using a stopwatch, count the number of pulse beats in 30 seconds. Repeat this measurement until you have a reliable result. Record the data in a table.

· Now take the pulse at the neck using two fingers when rested in a lying position for three minutes. Then take it again in after a further 3 minutes’ rest in a sitting position.

· Now take exercise for 5 minutes. This is step-up as your own pace.

· Take the pulse again only measuring it once.

· Measure the pulse rate again 2 minutes after the exercise has ended.

I will be taking 6 readings with 60 seconds difference in length.

I will be repeating the experiment twice. One will be the resting heart rate; the other will be the heart rate straight after the exercise. I will compare them to work out an average. This is done because the first time the person’s heart rate might be faster than normal because of the anticipation of the experiment and therefore might be a bit excited. I will average the two readings to make it fair.

Before starting I have to make sure that the person performing the exercising is in reasonable physical condition to exercise.

Results: -
Time (min)

Heart Rate (per minute)

First

Second

Average

0

64

62

63

1

69

68

69

2

96

100

98

3

114

119

117

4

139

141

140

5

143

147

145

Conclusion: -
The graph shows that the heart rate didn’t increase a huge amount for the first minute but then increased ver steeply for most of the rest of the exercise. However, during the final minute the heart rate doesn’t increase much more. This could be because the oxygen supply to the muscles had decreased. , a lot of energy was used up and the body was unable to continue aerobic respiration and anaerobic respiration took place instead. This resulted in lactic acid being formed. After exercise the heart rate does not return back to the resting heart rate straight away. This is because during the exercise anaerobic respiration begins to take place therefore the body has to pay back the oxygen when it is resting that’s why I felt short breathed after exercising and had to breathe in deeply to retain a lot of oxygen.

Evaluation: -
I think my investigation produced good results. But was not particularly accurate. For example I could not be sure that when doing the step