Factor affecting pulse rate Essay

Our heart is a muscle. It’s located a little to the left of the middle of our chest, and it’s about the size of our fist. There are lots of muscles all over our body — in our arms, in our legs, in our back etc. But the heart muscle is special because of what it does. The heart sends blood around our body. The blood provides our body with the oxygen and nutrients it needs. It also carries away waste. Our heart is sort of like a pump or two pumps in one. The right side of our heart receives blood from the body and pumps it to the lungs. The left side of the heart does the exact opposite: It receives blood from the lungs and pumps it out to the body. Every time when blood travels through heart it produces a sound called lub-dub. Lub happens when the upper chambers of the heart contract to squeeze the blood downward into the ventricles. A dub happens when the lower chambers contract. Every time the lower chambers of the heart contract, the blood in the left ventricle rushes upward into the aorta. It quickly speeds away from the heart causing the aorta to expand as it passes. As the blood races along, some of it pushes into the first artery that branches off from the aorta. Some of the blood enters the next artery. The blood from each contraction of the heart produces a bulge in the artery. This bulge of the arteries is called a pulse. One pulse is equal to one Heartbeat. The rate at which heart beats is called pulse rate. It can be varied by various factors such as:- Body Build and Size. A short, fat person may have a higher rate than a tall, slender person. The larger the size, the slower the rate. For example, a grizzly bear has a heart rate of about 30 beats a minute while a hummingbird’s is about 200 beats per minute. Gender: a woman’s heart rate is generally faster than a man’s. Age: generally the younger a person is, the faster the heart rate. An infant’s heart rate is about 120 beats per minute; a child’s is around 100; an adult’s is between 70 and 80; an elderly person generally hovers in the 60s. Exercise and Muscular Activity. An  increase in pulse rate will occur with increased activity to meet increased oxygen and nutrient demands. A regular aerobic exercise program can lower the resting pulse. A person, who exercises a great deal, such as an athlete, will develop bradycardia that is a normal, health condition. The body slows the heartbeat to compensate for the greater volume of blood pumped with each beat. Emotional Status. Fear, anger, and anxiety will all increase the pulse rate. Hormones: influence heart rate, especially epinephrine, norepinephrine, and thyroid hormones, all of which can increase the rate. Pathology: certain diseases affect heart rate, causing it either to slow or to race. Medications and drugs: Stimulants will increase the pulse rate; depressants will decrease the pulse rate. For example, Digitalis slows the rate, while epinephrine (Adrenalin) increases it. Caffeine can also cause palpitations or extra beats. Blood Pressure. As the blood pressure decreases, the pulse will frequently increase. Elevated Body Temperature. The pulse increases approximately 10 beats per minute for every 1 F (0.56 º C) increase in body temperature. These conditions cause a temporary increase in the heartbeat and pulse. Pain. When the patient is in pain, the pulse rate will increase. Hypothesis I think that exercise will vary the pulse rate because when we are working out or exercising, oxygen is released from our body more rapidly as the cells metabolize and use up the oxygen quicker, and so our body requires a greater amount of oxygen. Due to which our heart rate increases to carry oxygenated blood to our muscles and organs. Hence, increasing our pulse rate. Variables Independent Variable: In this the independent variable is exercise because the pulse rate is varied by the exercise we do. Dependent Variable: In this the dependant variable is the pulse rate because it is dependent on exercise and many other factors that are kept constant. Constant Variable: In this all other factors excluding exercise are kept constant. This allows us to measure the effect of exercise on pulse rate and minimize confounding effects due to any other factors that may influence heart rate. Apparatus and Procedure Stop watch 1. Sit down comfortably on a chair, locate the pulse and calculate the number of pulse per minute. 2. Walk gently measuring different feet and calculate the pulse rate after each distance. 3. Repeat these steps twice and calculate the average number of pulses per minute and record. Observation table 1. Person-1 Pulse rate after walking 1 2 3 Average pulse rate At rest 74 72 77 74 100 feet 74 77 78 76 200 feet 77 79 76 77 300 feet 81 85 82 82 400 feet 87 84 89 86 500 feet 93 91 96 93 2. Person-2 Pulse rate after walking 1 2 3 Average pulse rate Pulse rate at rest 70 75 73 72 100 feet 73 72 77 74 200 feet 78 74 80 77 300 feet 79 81 83 81 400 feet 85 82 88 85 500 feet 91 94 98 94 3. Person-3 Pulse rate at rest 1 2 3 Average pulse rate Pulse rate at rest 73 72 75 73 100 feet 77 84 87 82 200 feet 94 96 93 94 300 feet 104 106 107 105 400 feet 104 110 108 107 500 feet 106 109 104 106 Conclusion BY observing my graphs I came to the conclusion that exercise raises the pulse rate because When the body is exercising the muscles respire to produce energy, so the muscles can contract. Oxygen is needed, the oxygen is carried in the haemoglobin of the red blood cell. The heart and lungs need to work harder in order to get a greater amount of oxygen to the muscles for respiration. In muscle cells digested food substances are oxidised to release energy. The heart rate rises because during exercise, respiration in the muscles increases, so the level of carbon dioxide in the blood rises. Carbon dioxide is slightly acid; the brain detects the rising acidity in the blood, the brain then sends a signal through the nervous system to the lungs to breathe faster and deeper. Gaseous exchange in the lungs increases allowing more oxygen into the circulatory system and removing more carbon dioxide. The brain then sends a signal to make the heart beat faster. As a result this, heart rate would rise. My graph confirms my hypothesis in that as the length of exercise is increased, the number of beats per minute rises. Hence the result shown by our experiment seems to be correct. Therefore I think that the procedure we used was reliable. Although there are some sources of error but these do not makes much difference and can be ignored. Sources of error As experiment is fully performed by humans so there are some human errors involved in the experiment. Firstly, we didn’t use pulse rate meter so there may be some errors in counting the pulse rate making some changes to our  result. Secondly, the person might not have properly relaxed so; factors like stress, excitement can affect the pulse rate making changes to our result. Thirdly, it took time to count the pulse rate after exercise, because of which the increased pulse rate might have come to normal in this meantime. Improvements By making some improvements in our experiment we could get more better and exact result. For example Instead of counting the pulse we could have used pulse rate meter to calculate pulse rate. Secondly, we could have taken pulse rate of more persons for better and accurate result.