Aim: To find out how exercise affects the human body, by measuring changes in pulse rate and blood pressure.
The glucose is broken down in our tissues into Adenosine Tri-Phosphate (ATP). ATP provides energy for processes such as muscle contraction (the process needed for exercise). The glucose and oxygen necessary for respiration are transported to the cells through the blood stream. The heart muscles contract to pump the blood around the body to the cells, providing the substances needed for respiration. When you exercise the muscle cells (which muscles are made of) need to contract more than usual, requiring more energy. To produce more energy the cells need more oxygen and glucose than they would usually receive. In order to supply the heart muscles contract faster. This increased rate of contraction increases the blood pressure, transporting the blood round the body faster. The increased rate of contraction can be measured through pulse rate or taking blood pressure. Glucose enters the blood stream through the digestive system but oxygen is absorbed into the blood stream through the lungs. Oxygen is taken into the lungs and diffuses into the blood stream. The oxygen is transported round the body to the cells in this manner. In order to prove that these are the effects of exercise on the body I will need to conduct an experiment. I will exercise for varied periods of time or for varied periods of distance and I will record my number of breaths and pulse rate for one minute after exercising. I will also record my pulse rate and breathe rate at rest. This should prove that both increase after exercise. To choose an exercise and to determine whether I should use distance or time I will conduct a preliminary experiment.
1. Use the metre rule to measure a distance of 62 metres.
2. Measure the pulse (at the neck or the wrist) per minute and number of breaths per minute.
3. Jog the 62 metres (1 length).
4. When you have finished jogging record your pulse rate and number of breaths for one minute.
5. Jog 2, 3, 4, 5, 6, 7, 8, 9 and 10 lengths, recording pulse and number of breaths per minute after each period of jogging.
6. Repeat each number of lengths at least 3 (preferably 5 or more) times.
My results helped me choose an exercise to use for my experiment. running and bike were all too exhausting to keep up for long periods of time (they gave an extremely high pulse and breathing rate for just one minute of exercise). Step ups, sit-ups and power walking gave fairly low results, meaning that they might give insignificant changes after brief periods of exercise. Jogging gave a good mix between the two so I decided to use jogging as my chosen exercise. After choosing jogging I needed to find out whether time or distance was more appropriate for my final experiment. I jogged for 1-5 minutes and I jogged 62-310 metres (62 metres was the length of a tennis court I used as a measure of distance). After jogging I took my pulse rate and breathing rate for one minute each.
The exercise would have to give clear results that would make a significant difference to blood pressure and pulse rate, without giving too drastic a change. If the change was too drastic it would be difficult to keep up the exercise for a long time or distance. I recorded results for eight different exercises, doing each exercise for one minute before taking pulse rate for one minute and breath for one minute.
Overall the evidence obtained was fairly accurate and reliable. I recorded several results for each distance in order to get a reliable average and to ensure that the results were not incorrect or abnormal. The results were not as accurate as they should have been, however. Two results, one for number of blood pressure and one for pulse were anomalous and had to be redone. The measurements taken were accurate as far as they go, but number of breaths per minute is ambiguous. The tidal volume (depth) of the breaths may vary over the minute they were being recorded, with breaths at the beginning of the minute being deeper than those at the end (due to the fact that less energy is needed just after an exercise than is needed a short time after the exercise). The procedure was relatively accurate and allowed plenty of opportunity for repeats. The procedure could have been improved if lengths with replaced with a continuous circuit, as more energy is required for turning and you need to slow down to turn. The main problem with the procedure was that there was no foolproof way of keeping the pace constant. This could perhaps have been rectified through the use of an electronic treadmill. On an electronic treadmill you set a speed and your pace must remain the same otherwise you run out of space to jog on. The evidence is firm enough to support my conclusion, although more evidence is needed to confirm it. The evidence is also reliable as a reasonable amount of repeats have been conducted. To provide firmer results, more repeats should be performed over a wider range; preferably using more than one person (I used only myself in this experiment). Two anomalous results were recorded. The first was a pulse rate of 123 after having run 310 metres (the other results recorded were 169, 171, 174 and 170).This anomaly was the result of losing count during the reading. The second anomaly was 40 breaths after running 620 metres (the other results were 57, 54, 59 and 52). This anomaly was a result of accidentally stopping the count before one minute had passed.
As can be seen after exercise pulse rate and breathing rate increased. The pulse rate went up quite quickly at first, before slowly levelling off. Breathing rate increased steadily and slowly began to level off. The reason for this increase is due to the energy required for exercise. When running the muscles contract to make move. To be able to contract they need energy. They produce this energy through a process called aerobic respiration:
As can be seen Glucose and Oxygen are required to produce energy that muscle cells need to contract. Glucose and oxygen are taken to the cells in the blood stream. Glucose is taken into the blood stream through the digestive system. Oxygen is taken into the blood stream through the lungs. When humans gasp (breath in) the oxygen that is inhaled diffuses (diffusion is the random movement of molecules from a region of high concentration to low concentration) into the blood stream. The oxygen diffuses through the alveoli, which are microscopic “bubbles” in the lung. A network of capillaries (tiny blood vessels) surrounds these alveoli and it is through these that oxygen enters the blood stream. In the blood there are red blood cells. These cells contain chemical called haemoglobin, which attracts oxygen. The oxygen is absorbed into the red blood cells and forms a compound with the haemoglobin, called ox haemoglobin, the heart muscles contract, forcing the blood round the body. The oxygen is transported round the body in the red blood cells; to where it is needed (it is needed in all cells as they must all carry out respiration to survive). When you exercise the muscle cells need to produce more energy than usual, so they need more oxygen and glucose than usual. To allow this to happen, your breathing rate must increase. You take in more breaths and your tidal volume the depth of your breath increases, Muscles in between your ribs contact, moving up and out and your diaphragm (a sheet of muscle at the bottom of your chest cavity) contracts, moving down. This increases the volume in your thorax (chest cavity), decreasing the pressure. Air rushes down to equalise the pressure. When you exhale your intercostals muscles and diaphragm relax, moving back to their original positions. The pressure is increased in your thorax so air rushes out to equalise the pressure. Your intercostals muscles and diaphragm contract more quickly and contract more than they usually would, to allow a greater amount of deeper breaths. Glucose and oxygen must still be transported to the cells, however. To accomplish your heart muscles contract more rapidly. This increases the blood pressure, forcing it round the body faster. This helps transport the oxygen and glucose to the muscle cells quicker. Also, it makes sure that plenty of blood is circulating around the capillaries in the lungs, so that more oxygen can be absorbed into the blood stream.