To keep this experiment fair I will control and keep the same all the other variables that I can find in this experiment. I will control the type and speed of the exercises done because different exercises may require more energy and so affecting the heart rate result gained and thus giving inaccurate results. I will do this by making sure that the person is always jogging on the spot before and during the experiment. We will also make sure that we measure the heart rate of the person straight after they have done the exercise otherwise the heart rate will gradually slow down and give an inaccurate result. We will also make sure that a person’s heart rate is back to normal before they undergo more exercise because otherwise the heart rate result will be affected and thus inaccurate. We will also keep things like the place, the conditions and the timer used the same to avoid any small errors in measurement. To achieve most of the things above we will make sure that there are always two people monitoring the experiment and checking the timer to make sure that the experiment runs smoothly and that we get accurate results. We will not keep the person doing the experiment the same because we want to get a wider range of different types of fitness levels to get more reliable results.
To make my experiment safe I will make sure that the people doing the exercise have appropriate shoes and that they tuck all lose items of clothing in to be safe while doing the exercise. I will also make sure that no one overdoes the exercises in the experiment so the no one gets hurt or injured.
Method: First we checked the heart rate of three different people at resting point for 1 minute and then we started the first person off, jogging on the spot for 30 seconds and then checked his heart rate for 1 minute after the exercise. We then did the same for the second and the third person checking their heart rate for 1 minute after the exercise. We then checked that the first person’s heart rate was back to their normal resting rate and started them off on a 1 minute and 30 second jogging on the spot exercise and recording their heart rate for 1 minute after the exercise. We then repeated this experiment 5 more times on each person, advancing the exercise time 30 seconds every time and measuring their heart rate immediately after the exercise. We then repeated the whole experiment again on all three people and put our overall average results onto a graph.
Results: Dean - resting heart rate 57 beats per minute
Gareth - resting heart rate 66 beats per minute
Guillaume - resting heart rate 69 beats per minute
Average - resting heart rate 64 beats per minute
Guillaume Wright 9C2
C/W How does exercise affect your heart rate? 10/6/00
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Conclusion: From our experiments that we done we have concluded that as the amount of exercise undertaken by a person increases the faster (higher) their heart rate will be. This is because when a person undertakes any movement or exercise they need oxygen to be taken in by the lungs and transferred to blood cells through the capillaries in the body and for the blood to transport the oxygen (and glucose) to all the body cells by being pumped around by the heart, so that they can use these two things in respiration (a reaction that takes place in every cell in the body) to produce water, carbon dioxide and most importantly energy so that the body muscles can do the necessary movement to do the exercise. When the exercise time is increased the need for oxygen to the muscles increases so that more respiration can take place to produce more energy for the muscles to work harder and for longer. For this to happen first the breathing rate increases to allow more oxygen into the blood stream and the heart rate will increase as the blood will need to be pumped around the body quicker to supply the necessary components for respiration to the body cells to produce the increased amount of energy for the longer period of exercise.
Another thing that I have concluded from graph results is that of the relationship between the two factors is not as simple as it looks. I have observed that as the exercise time increases the smaller the gap between one result and the next get. For example the gap between the first two heart rate results (at 30 seconds and 60 seconds) is 32.83 beats per minute, but the gap between the second set of results (at 60 seconds and 90 seconds) is 14.77 beats per minute and this tend carries on throughout the line and suggests why the line is curved and not straight suggesting the decline of the gradient of the line. This suggests that the relationship between the two factors is not that of a straight line (linear) but one of a parabolic curve which is one where in this case something is gradually being overcome by another factor which suggests why the gradient of the heart rate line decreases because there must be another factor that opposes the heart rate getting faster and gradually begins to slow the rate rise down, creating a parabolic curve. For example if a ball was thrown in the air the initial force of the throw would take the ball up in the air but as it loses the energy the opposite force (gravity in this case) begins to take over and have an adverse affect on the ball bringing back down to earth, which is very similar to what the line of best fit on our graph suggests. In mathematical terms there must also be two constants involved in the equation, the first is the maximum heart rate and the second is the resting heart rate and would also involve another constant divided by the exercise time (x axis). For example from a rough estimate that I have tried out on my calculator is y = 150 - 10000/x + 64 but the formula may be more complicated and involve other factors and would be an interesting point to try and work on.
Evaluation: Overall our experiment was very good and it went very well with nothing really going wrong and no real problems in achieving or in concluding our results. We managed to set up the experiment well and the whole thing ran very smoothly with no problems encountered with our plan during or after our experiment. We achieved the expected results on the whole but there was a bit of tricky explaining to do about the parabolic curve that we ended up with. The experiment was easy and there was no real tricky things to do.
In my opinion we haven’t really got enough results to rightly predict the way in which exercise affects our heart rate and although our results strongly suggest this fact we could have made our results more accurate and reliable. We could have done the experiments more densely by increasing the exercise time by 10 seconds every time and also increasing the exercise range from 10 seconds to
600 seconds so that we could get more accurate results. We could have also done the whole experiment more times e.g. 5 times to get more reliable results and we could also have tested more people at different levels of fitness to get a better range of results for more accuracy.
Overall our results were very good any only one result was slightly off the line of best fit (second result at 30 seconds) and this could either be because of inaccurate measure of this exercise time in all three people, or that there is something else e.g. the resting heart rate result that affects the line of best fit so that it appears to not fit in with the line of best fit because another constant result may be affecting the line.
We could improve the experiment that we have done by doing the above suggestions for improving the reliability and the accuracy of the results. We could improve the accuracy of the measuring of the experiment by doing it in milliseconds and also measuring the heart rate for only 10 seconds after they have done the exercise and multiplying this by 6 so that the heart does not get a chance to go back to it’s normal resting rate and there is less room for inaccurate measure. We could also repeat the anomalous result to check whether its just a measuring error or in fact it is what we have mentioned above about the interference of another point. To extend our experiment we could also see if the same rule applies to other types of exercise and suggest why. We could also see what happens when we go to both extremes of the line graph and see what happens when the opposing force finally forces the heart rate to stay the same and if you can ever reach the maximum heart rate and what happens when or if you do. We could finally investigate further the mathematical formula behind the line and see why this is using science so that we could use this in estimating and draw up more complicated conclusions from it.
