The effect of exercise on the heart rate.
AT1
THE EFFECT OF EXERCISE ON THE HEART RATE
Plan and Prediction:
I will conduct an experiment accurately and suitably, which will give evidence to prove my prediction correct.
Firstly I will carry out preliminary tests, which will tell me which exercise will raise the heart rate more and give the best results. The exercises I will test are: step-ups, skipping, sit-ups and jogging on the spot. To test these different exercises I will time each of the exercises for thirty seconds then measure the heart rate. I will repeat these preliminary tests to ensure the results will be fair.
Unit of exercise
Heart rate after 30 seconds of exercise (bpm)
2
3
AVERAGE
Jogging
16
20
24
20
Sit-ups
88
00
12
00
Skipping
36
12
96
15
Step-ups
84
92
80
85
These preliminary tests showed that jogging increased the heart rate the most and as long as it is kept at a constant pace the results should be accurate. This is the exercise I have chosen to do for the experiment.
I will measure the resting heart rate of the person exercising by counting the number of beats per minute (bpm) in fifteen seconds and multiplying it by four. I will then take the bpm after the person has done thirty seconds of exercise, then again after forty and so on adding an amount of ten seconds each time up to ninety seconds.
I will display the information I get clearly on a results table and on a graph showing the line of best fit.
I must make sure that the experiment is a fair test in order to produce precise and reliable evidence for my prediction. I will ensure this by repeating the experiment so that from all three experiments I will find an average. I will also make it a fair test by measuring the time and bpm accurately and that the person exercising keeps constantly at the same pace. To allow the measurements of heart rate to be accurate I will need to let the person exercising to rest after each lot of exercise to allow their heart rate to return to resting. As well as this, the experiment needs to be a safe test. I will make sure it is safe by checking the person exercising is wearing appropriate clothing and footwear, that they are exercising on even ground and they have warmed up and stretched.
I predict that the heart rate will increase and the more exercise the person does the higher their heart rate. I know that the heart pumps blood around the body. As the body exercises the demand for glucose and oxygen, that respire and produce energy, increases. Therefore the heart rate will increase the longer the person exercises to meet this demand.
The heart rate is the rate at which the heart pumps blood around the body. It can be measured by a pulse, which can be taken from a main artery (on the wrist, neck or groin. ...
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I predict that the heart rate will increase and the more exercise the person does the higher their heart rate. I know that the heart pumps blood around the body. As the body exercises the demand for glucose and oxygen, that respire and produce energy, increases. Therefore the heart rate will increase the longer the person exercises to meet this demand.
The heart rate is the rate at which the heart pumps blood around the body. It can be measured by a pulse, which can be taken from a main artery (on the wrist, neck or groin.
When the heart pumps it's muscles relax allowing blood to flow into the atria from the veins. The atria then contract squeezing blood into the larger and more muscular ventricles. When the ventricles contract the blood cannot flow backwards because of valves in the heart. The blood is forced out of the lower chambers and into two arteries. After this the whole process starts again by the heart muscles relaxing.
The heart pumps in order to circulate blood. The circulatory system is a double system, the right side of the heart pumps deoxygenated blood to the lungs via the pulmonary artery. At the lungs gaseous exchange takes place where carbon dioxide is exchanged with oxygen. The oxygenated blood is transported back to the heart. At the heart it is pumped to all parts of the body via the Aorta. The heart beats faster during exercise in order to carry the substances needed for respiration in the blood to the respiring cells.
There are four components to blood, the red cells, the white cells, the plasma and, the platelets. The red cells transport oxygen from the lungs to the organs in a red pigment named haemoglobin. The white cells are one of the bodies defence mechanisms against germs, they destroy and engulf invading microbes and produce antitoxins and antibodies to fight poisons and disease. Plasma is the liquid part of the blood; it transports carbon dioxide from the organs to the lungs, glucose from the small intestine to the organs and other wastes such as urea from the liver to the kidneys. The platelets are another of the bodies defence mechanisms against germs, they clump together when a blood vessel I damaged and form a meshwork of fibres to produce a clot.
Glucose is enters the body through eating carbohydrates. All carbohydrates, whether complex or simple, are digested in the body to form glucose, which is transported around the body via the blood and taken into cells to be converted into energy. Excess glucose is converted into glycogen, which is stored in the liver or in fat around the body. If the body needs more energy, glucagon converts the glycogen back into glucose. It is then released back into the bloodstream.
During respiration oxygen is used to release energy from glucose. Energy is vital during exercise. In this case of exercising the respiration that will occur will be aerobic. Aerobic respiration is the release of energy from the breakdown of glucose by combining it with oxygen inside living cells. The equation is:
Glucose + Oxygen ==> Carbon Dioxide + Water + Energy
The glucose and energy are brought to the respiring cells by the bloodstream. The carbon dioxide is taken by the blood to the lungs, and exhaled. The water passes into the blood and is lost as sweat, moist breath and urine. The energy is used for muscle contraction, metabolism and maintaining temperature. Muscle contraction needs to occur during exercise therefore needing an increased amount of energy brought by the blood stream.
During our experiment the circulatory system, the digestive system and the respiratory system will all work together to ultimately provide energy for the person exercising.
Obtaining Evidence
Duration of exercise (sec)
Heart rate after exercise (bpm)
2
3
AVERAGE
30
84
80
84
83
40
92
88
12
97
50
08
96
32
12
60
16
32
48
32
70
20
36
36
31
80
28
52
56
45
90
32
56
56
48
Resting heart rate= 64 bpm
Analysis
This graph displays the average recordings from my experiment.
As you can see my results support what I had predicted, as the heart rate did increase during exercise in relation to the amount of time spent exercising. This is because as the body exercises the cells require faster supplies of oxygen to respire and produce energy, which is needed for muscle contraction, and to remove carbon dioxide. Therefore the heart beats faster to circulate the blood.
The graph shows a steady increase in heart rate up to 80 seconds of exercise and then flattens out slightly up to 90 seconds. This could suggest that having reached a certain level, the increase of heart rate slows down. This relates to the body's ability to regulate the supply of energy to the cells and demonstrates the way that all of the body's systems work simultaneously.
One reading in the results shows a slight drop in heart rate at 70 seconds of exercise. This is an anomalous result and is probably due to a fluctuation of heart rate that can occur during exercise. This reading does not affect the overall pattern of the graph.
Evaluation
The results I got from the experiment clearly displayed that my prediction was correct.
The results were fairly accurate. The graph displays a pattern that I expected, the increase of heart rate at a steady pace, apart from the one anomalous result.
The anomalous result on the graph was because it was taken from the average readings of the repeated tests, which had quite dissimilar readings. In the third test there was an anomalous result. This could be due to a fluctuation in heart rate, or an inexact measurement of the beats per minute or the duration of exercise.
My results are moderately reliable. In each of the tests the hear rate increased during exercise. The numbers of beats per minute, recorded after each duration of exercise, on each of the repeated tests were different. This could be because the tests were done on different days. The person exercising may have eaten more or less energy supplying foods and the amount of energy that they have used for other things, such as maintaining temperature, would vary. To improve the method to make it more reliable I would do each of the tests on the same day and allow a sufficient length of time to rest between the exercising to allow their heart rate to return to normal resting rate. I would also ensure that the pace of the exercise was constant throughout all the tests.
For ultimate reliability instead of using a stopwatch to time the duration of exercise, and using your fingers to count the beats per minute on your neck I would use a heart monitor connected to a computer that would display the results in an on-going graph. This would allow the person to continue the exercise whilst the heart monitor records the heart rate instead of exercising for a short period of time then taking their pulse, allowing it to return to normal and starting again. I would also use a treadmill instead of jogging on the spot. This keeps the exercise at a constant rate and records the exact length of time, and occasionally the distance, the person exercising has done.
To provide a more reliable way of testing my prediction I would widen my range of results. To do this I would lengthen the amount of time exercising to investigate what happens when the person exercising reaches a certain point and weather when they reach this point their heart rate no longer increases. I would display all of the data in a graph.
The conclusion I have come to is valid as I know that although the evidence I have gathered is perhaps not as reliable as it could be, if I were to repeat this investigation I know which area's need improving and I would then be able to produce a better display of evidence.
Jo Cunningham
0P2