Prediction:
I predict that the greater the intensity of exercise done, the higher the pulse rate after exercise will be. Consequently, the pulse rate will take longer to return to the resting pulse rate, and the recovery rate after the more intense exercise will be longer than the recovery rate after the less intense exercise.
Prediction Reasoning:
As explained previously, when you exercise, the body responds to the particular exercise by immediately increasing the heartbeat. This is in order to pump more oxygenated blood around the body to be diffused through blood capillary walls and tissue fluid into your muscles and other body tissues where it is required for respiration. (RESOURCE 1) During vigorous exercise, your heartbeat may rise to 150 beats per minute or more (compared to 70 or 80 heartbeats per minute at rest, for the average person). The exact increase in pulse rate is dependant on the temperature (which must be controlled) and the intensity of exercise. (RESOURCE 2)
Also, the breathing rate must dramatically increase in order to supply the need for oxygen to drive aerobic respiration, or break down lactic acid, produced during anaerobic respiration. Also, the body’s metabolic rate, which depends on how many calories you're burning, can increase greatly, depending on how hard you exercise. (RESOURCE 3)
Key factors to vary: Variables:
Apparatus list:
The following apparatus will be required, to be used in the experiment:
- Stopwatch / time measuring equipment
-
Heart rate monitor (optional)
- Trundle wheel / measuring tape
- Thermometer
- Calculator
Plan:
Firstly, all apparatus required will be organised and arranged in the area in which the exercise will take place. Firstly, 30 metres will be marked out in a straight line, using the trundle wheel. Then, the person completing the exercises will measure and record their resting pulse rate (measured in beats per minute). Then, the person will run the 30 metres marked out as quickly as possible, and their time will be recorded. After the exercise period, the person’s pulse rate will be measured for one minute, and recorded. A one-minute resting interval will be carried out, and then the pulse rate measured and recorded again. This will continue until the pulse rate returns to the resting pulse rate. The recovery rate will then be worked out. This entire exercise will be repeated by the same person, as before – for accuracy of the results.
After this, a second intensity of exercise will be carried out. Firstly, an area in which an exercise of 30 step-ups can take place will be found. Next, the person’s resting pulse rate (measured in beats per minute) will be recorded again. The exercise of exercise of 30 step-ups will be completed, and their time will be recorded. After the exercise period, the person’s pulse rate will be measured for one minute, and recorded. A one-minute resting interval will be carried out, and then the pulse rate measured and recorded again. This will continue until the pulse rate returns to the resting pulse rate. The recovery rate will then be worked out. This entire exercise will be repeated by the same person, as before – for accuracy of the results.
Resources Used:
Results:
Conclusion:
From the results shown above, I conclude that the initial prediction, that ‘the greater the intensity of exercise done, the higher the pulse rate after exercise will be’ is correct. However, the second part – stating that ‘the pulse rate will take longer to return to the resting pulse rate, and the recovery rate after the more intense exercise will be longer than the recovery rate after the less intense exercise’ is incorrect. This is what would be expected, but the recovery rates were in fact the same for both exercises. In reality, though it could be concluded that the first intensity of exercise was the more intense of the two exercises completed and repeated. This evidence is gained from the graph shown above.
The first intensity of exercise (30 step-ups) was the more intense of the two exercises completed. This is found because the pulse rates after the first exercise shown on the graph are higher than those at similar times after the second exercise was completed. The reason for the greater pulse rate after the first exercise is due to the fact that the body required more oxygen to be supplied to the muscles and other cells for respiration. Consequently the pulse rate was increased (probably by the high carbon dioxide and lactic acid levels in the blood from aerobic and anaerobic respiration). This was in order to pump blood around the body quicker, supplying oxygen to these cells.
Overall, pulse rate and intensity of exercise are proportional. The greater the intensity of exercise, the higher the body pulse rate is – after exercise. This is explained in the previous paragraph.
Evaluation:
Overall, the results obtained were fairly accurate in the experiment conducted. Inaccuracies with the conduction of the experiment may have been brought about by the following problems:
- All measurements were gained using manually controlled equipment, which relies on the accuracy of the human eye (such as in the use of a stopwatch).
- The resting pulse rate, and pulse rates taken after the exercise were also taken manually. Mistakes are common when taking the pulse rate, and this could have changed the out coming results considerably.
- As a result, the recovery rate of the person completing the two different exercise could only be measured to the nearest minute.
Furthermore, the procedure had a few problematic areas, mainly concerning the controlled variables:
- Two of the four controlled variables were actually controlled with accuracy, being ‘metabolic rate’ and ‘lung capacity’. These two variables were always the same, as the experiment was conducted with the same person every time.
- The third control variable, ‘energy consumed’ was controlled, but not with great accuracy. No extra energy intake was present, but the energy within the body was not measured – so some energy may have been lost after certain exercises. This could have affected the results slightly, but not considerably.
- The fourth control variable could not be controlled whatsoever under the circumstances. The temperature of the surroundings was changing constantly, during the conduction of the experiment. This could have had an effect on the pulse rate of the person completing the exercises.
As explained, the results are fairly accurate, and the evidence is reliable, but the inaccuracies of measurements (degree of error) could have had an effect on the results, as could the variables that could not be controlled – ‘temperature of the surroundings’. The measurements of pulse rate, accounting for degree of error could have been 1b.p.m. The measurements of recovery rate, accounting for degree of error could have been 30 seconds (0.5 minutes). The differences in temperature during the conduction of the experiment could also have been approximately 1degree. These three factors could have affected the results, but not greatly. Therefore, I feel that the evidence gained, in conjunction with the graphed results found is sufficient to support a firm conclusion as shown.
In order to improve the accuracy of the evidence further, the following changes could be made to the overall experiment:
- Electronic measuring devices could have been used to measure the pulse rate changes with great accuracy before, during and after the exercises were completed.
- Electronic measuring devices could also have been used to measure the recovery rate of the person with greater accuracy.
- Other more effective outcome variables could have been used in place of ‘recovery rate’ that was used. These would have required the use of very complex systems that measure ‘breathing rate’ and ‘depth of breathing’.
- To overcome the temperature differences present with the experiment, the exercises could take place in a controlled environment, such as a sports hall where the temperature could be kept at a constant.
