Control Variables. I will keep the test fair by moving over a marked out distance of 30m each time I complete exercise and I will make sure I count my heart rate starting from the exact moment I have stopped doing my exercise.
Prediction: From my scientific knowledge 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 then 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 believe that the supply of Oxygen to the muscles will decrease which will push the heart rate up. I also think that a lot of energy will be used up as the exercise takes place, thus resulting in a 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 rising.
Equipment: Stopwatch, sport shoes.
Method: I am going to carry out three different movement exercises, walking, jogging and running. The heart rate will be taken by feeling the pulse in the wrist.
Here is the procedure of the experiment:
- The resting pulse will be taken and recorded.
- I will then walk 30m, one width of the school field outside the science labs.
- As soon as I have completed my exercise I will take my heart rate by placing two fingers on my wrist and counting the pulses.
- I will then record my results.
- I will check my current heart rate every minute until it returns to its resting heart rate.
- Once my heart rate has returned to its normal heart rate I will repeat the exercise and the steps above twice more waiting in between each set for my heart rate to return to its resting rate.
- Once I have walked 30m three times I will move onto jogging the distance. But I will make sure my heart rate has returned to normal before making the change from one exercise to another.
- As soon as I have completed my exercise I will take my heart rate by placing two fingers on my wrist and counting the pulses.
- I will then record my results.
- I will check my current heart rate every minute until it returns to its resting heart rate.
- Once my heart rate has returned to its normal heart rate I will repeat the exercise and the steps above twice more waiting in between each set for my heart rate to return to its resting rate.
- Once I have walked and jogged 30m three times each I will move onto running the distance.
- As soon as I have completed my exercise I will take my heart rate by placing two fingers on my wrist and counting the pulses.
- I will then record my results.
- I will check my current heart rate every minute until it returns to its resting heart rate.
- Once my heart rate has returned to its normal heart rate I will repeat the exercise and the steps above twice more waiting in between each set for my heart rate to return to its resting rate.
- Once I have walked 30m three times I will move onto jogging the distance. But I will make sure my heart rate has returned to normal before making the change from one exercise to another.
- As soon as I have completed my exercise I will take my heart rate by placing two fingers on my wrist and counting the pulses.
- I will then record my results.
- I will check my current heart rate every minute until it returns to its resting heart rate.
- Once my heart rate has returned to its normal heart rate I will repeat the exercise and the steps above twice more waiting in between each set for my heart rate to return to its resting rate.
- When I have finished collecting my data I will work out the averages and analyse my data.
Risk assessment: I will make sure I warm up correctly before I exercise so that I don’t injure myself and I will wear trainers so that I don’t slip.
Preliminary work: There isn’t really any necessary preliminary work that needs to be carried out.
Results Table:
Conclusion: The graph shows that the heart rate didn’t increase a huge amount between resting and walking but then increased rapidly between walking and jogging and jogging and running. I think this happened because when the body had to jog or run the supply of Oxygen to the muscles needed to increase, because it was being used up at a rapid pace as the exercise took place. The heart needed to pump faster to get a sufficient amount of oxygen around the body quick enough Running and jogging was more strenuous than walking which is why I believe that the pulses didn’t increase as rapidly for walking. I also believe that the CO2 levels rose which also contributed to the heart rate rising.
Evaluation: Although I believe that my experiment produced fairly valid results, I am not sure that my experiment was particularly accurate. For instance, I cannot be sure that the same exercises were done at the same rate throughout the experiment. Also, I can not be sure that the distance was 30m as this was secondary information.
If I were doing this experiment again I would have to look closely at the method of exercise I used. I think that exercising on a piece of equipment like a running machine would produce more accurate results because I would be able to guarantee that the exercise remained constant throughout this experiment.
Finally, an actual ‘pulse-meter’ might have helped the experiment to be more accurate. This is simply strapped round the chest of the exercise and it measures your current heart rate. I believe that this would produce a more accurate heart rate.
If I were to extend my experiment I could try different exercises such as star jumps and step ups at different paces to see if this has similar results.
