Biology - the heart rate
...ar pattern that shows participants with a healthy or under weight BMI have a small difference between their resting pulse rate and their pulse rate after exercise compared to the high difference I predict for participants who are overweight or obese. Getting my results To obtain results that will be of use in my investigation I selected 5 girls and 5 boys from Years 7 to 10. I wanted to have a small range of data to represent students from across the school but at the same time try to ensure a random sample. Participantsˇ¦ ages could not be too dissimilar because of the links between age and the development of the heart. I took a measurement of each individualˇ¦s height to the nearest cm (using metre sticks) and a weight measurement to the nearest kg (using bathroom scales). I used these measurements to work out the BMI of each participant and used the above scale to assess whether each individual was underweight, normal, overweight or obese. I then requested that each participant took a resting pulse rate then run up and down a set of steps two times before taking another pulse rate. I then recorded all the results and repeated the process after a 10 minute break to allow the heart rate to return to a regular resting pulse rate. How I made the test fair Before I could begin to collect my results I had to consider how I could make this a fair and equal investigation. To do this I decided that each participant would have to run up and down the same set of steps the same number of times. This would ensure that each participant had to run the same distance so their heart rate could increase accordingly without some participants gaining an advantage over others. The same instruments (the bathroom scales and metre sticks) were used all the way through the investigation to ensure that all our results were taken to an equal level of accuracy. I also used the same method of data collection all the way through to ensure that it was as fair as possible and all data collected was treated equally. I decided to use a larger sample size so as to get clear results and to make patterns that may have emerged more prominent. I also repeated all my heart rate readings twice then took an average so as to eliminate any abnormalities that may have occurred in the data. My Results Using the results I collected through the above method I compiled the following table of raw data: Key: „h U - underweight „h N - normal weight „h O - overweight „h O+ - obese My Graph Using the above data I produced the following graph to clearly show the relationship between BMI and the difference of the resting pulse rate and the pulse rate after exercise: Analysis By analysing my graph it is clear that there is no set relationship between BMI and the difference between the resting pulse rate and the pulse rate after exercise. This is clear because there is no real correlation between the points and there is a wide dispersion from my line of best fit. What I did find was that a patterned emerged in the different coloured points for each year group. Years 7s all had a low BMI and were mainly grouped at the higher difference area. Years 8, 9 and 10 gradually got a larger BMI and a lower difference, which finished with the year 10s grouped with a higher BMI and a lower difference. The increase in BMI across the Years could have been because as they got older and developed they grew in height and weight but mainly in weight as they became more muscular and especially in the case of the females collected more body fat. The decrease in the difference between the resting pulse rate and the pulse rate after exercise would have been due to the fact that young peopleˇ¦s heart rates beat a lot faster and decrease as they get older. A babyˇ¦s heart goes extremely fast (almost like ˇ§flutteringˇ¨) in comparison to an adults and during childhood and adolescence (the age group I focused on) the heart becomes stronger and is able to pump the blood in greater amounts with less beats and therefore deal with the strain of exercise better. This information was shown in my data even though I used a very small age range. My final conclusion is that although there is no direct relationship between Body Mass Index and the difference between the resting pulse rate and the pulse rate after exercise, both factors are affected by age, which relates to my knowledge of development in children and adolescence. It would have been interesting after seeing the relationship BMI and heart rate had with age, to see if there existed a similar relationship with the gender of individuals. Although these results do not agree with my original prediction I think they were very satisfactory and showed some interesting scientific facts. Evaluation I think the method I used in collecting my data was well suited to its purpose. The systematic data collection meant that each participant was treated equally and helped to make it a fair test and my table was well structured and I found it very easy to use. However, my data when put in a graph did not give me the results I needed to prove my prediction correct. There may have been a number of factors that led to this. One of these factors may have been because of the inaccuracy of the BMI. As I discovered during my preliminary work someone classified as an athlete could be measured as obese using Body Mass Index because of the density of muscle in comparison to body fat. This may have been the reason why a few participants who were classified as overweight or near the higher end of the normal weight group could had a lower increase between their two pulse rates. Another factor that could how add...