This should be a safe experiment, but to secure mine and other pupil’s safety I will ensure that everybody is standing well away from me.
There are some variables which I will not be able to control, and some which I will. For example, if I perform the first set wearing trainers and the second wearing school shoes the first set is likely to be a higher result because trainers are lighter and more comfortable than school shoes. This therefore is a controlled variable. I must perform all three sets wearing the same footwear in order to keep it a fair test. I have decided that I will wear trainers for the exercises because of the fact that they are more comfortable and yield higher results.
An example of an uncontrolled variable is if on I had a cold or another mild illness on the day I was due to perform the exercises. This would clearly affect my ability to perform to the highest level possible, as I would be finding it harder to respire.
To make the test as fair as possible I will use the same stopwatch and record the process of exercise and the time it took for it to return to resting pulse rate for the same amount of time.
Prediction
I predict that the rate of respiration will increase as a result of exercise. I think that there will be a gradual increase to begin with, but as the body has to work harder I believe that the heart 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 also think that a lot of energy will be used up as the exercise takes place, resulting in further increase. If the body is unable to continue aerobic respiration, anaerobic respiration will take place. This results in lactic acid being formed. Finally, the CO2 levels would also rise which would also contribute to the heart rate increasing.
I also predict that my first set of step – ups will produce slightly higher results than the following two. This is because although I will have a five – minute break between each set, I will be more tired than at first.
Results
Pulse rate (resting) Set no. No. of step-ups Pulse rate (after exercise)
72 1 83 112
72 2 79 107
72 3 82 115
average – 81 average – 111
Graph to show increase in pulse rate after each set of exercises
Analysis of results
The results and the graph show that exercise certainly does increase the rate at which blood is pumped around the body. In set one I finished with 83 step-ups and 112 beats for my pulse rate. In set 2 I finished with 79 step-ups and 107 beats for my pulse rate. This indicates that my pulse rate was slightly faster after I had done a few more step-ups in the same amount of time as before. Because I had completed a few more step-ups my heart was having to pump blood around my body faster in order for it to reach the muscles. This also shows some evidence for my prediction that I would perform at my best for the first set, but not as well in the others. However, the third set proved to be a slightly anomalous result because although I only performed one less step up than in the first set, my pulse rate was at its highest at this point. However, there was not much difference in terms of number of step ups in any of the sets, nor was my pulse rate very different, so this cannot be said to be a completely anomalous result.
Scientific knowledge:
During exercise the heart beats faster and there is an increase in cardiac output (CO). As the CO increases so does the pulse rate. The reason why the pulse rate increases during exercise is so that more blood can be supplied to the muscles of the body at a faster rate. The blood carries metabolites (glucose and amino acids) which are used up in respiration in the mitochondria within cells.
Glucose + Oxygen Carbon Dioxide + Water + Energy
Respiration produces energy and this is used for metabolism, muscle contraction, maintenance of temperature and moving materials across the cell (active transport).
Respiration also needs oxygen, which comes from increasing the rate and depth of breathing. This causes more oxygen to be taken in by the lungs and release more carbon dioxide as the waste product.
Conclusion:
In summary, the pulse rate increases with exercise. This is what I had predicted and this is what has been proven from the experiment. I feel that the results I collected were fairly accurate. However, they were not exactly accurate because I could not have possible timed the minute perfectly, and it would have been very easy to make a mistake when counting the amount of step – ups I did, particularly because I was doing them at a very fast pace. There are many ways in which I could change the investigation because I could change the independent variables, such as the type of exercise, recovery time or the amount of time to perform the exercise. Overall I would say that the experiment went as well as I expected.
