A factor that I will be able to control during the experiment could be the time which it will take for one person to do the experiment. It is important that I don’t take too much time on each participant as the process could be very tiring and the participant may have to leave for reasons such as going to work etc.
I can control who will take part in my experiment too. I will have one participant who is healthy and one who is unhealthy. It is also important that I find a suitable place to do the experiment where it is less likely for me to be interrupted and safe for the participant to carry out the exercise.
There will also be some factors that I will not be able to control however it is important that I identify these one factor that I will not be able to control is temperature. Where I do my experiment will depend on where I find the participant and at what time. The experiment could be done either inside or outside therefore it could be hot, too hot, cold or too cold.
The fitness of the participant could also affect my results. Another factor that I will not be able to control is whether the participant has eaten within 24 hours of the experiment or not. If the participant has eaten within’ 24 hours then their body may not be able to exercise throughout all the experiment until it is complete because of a pain in the stomach, weakness in legs etc.
An important factor that will not be able to be controlled is the time of day that the experiment takes place. My dad who will be participant number two will not be able to wake up early in the morning because he works night shifts. My uncle on the other hand works early in the mornings so he will be at work when I wish for the experiment to take place. This factor is going to affect my results hugely so I will have to think of a time when I will be able to conduct my experiment at the same time. I don’t think this is possible because when my dad goes to work my uncle’s shift finishes so he goes to bed therefore I don’t think I will be able to overcome this factor.
BACKGROUND INFORMATION
I have done some research and have picked out information which is relevant to my experiment such as breathing, aerobic and anaerobic respiration and effects of heart rate.
Each pump in the heart has two chambers, an entry chamber- the atrium and a pumping chamber- the ventricle. A one way valve helps the blood being pumped in the right direction and not the wrong way. The ventricles have thick muscular walls and when this contract the pressure inside increases and the blood is forced into the artries. This causes your pulse. When the muscles relax the ventricles expand and blood flows into them from the atria.
The heart beats about 70 times every minute, day and night. It is important that the heart has a good supply of oxygen in order to do this. Exercise increases the beats per minute. As the heart pumps blood into the arteries, there is an increase in pressure. If the blood pressure is too low, blood circulates around the body very slowly however if the blood pressure is high the blood circulates around the body much faster.
When the body is exercising the muscles respire to produce energy, so the muscles can contract. Oxygen is needed for this process; 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. These oxidation reactions are called cellular respiration. When muscles use oxygen in order to respire the process is called aerobic respiration:
Glucose + Oxygen Carbon Dioxide + Water
C H O (aq) + 6O (g) 6CO (g) + 6H O (l)
The total energy released is:-
Energy released = 16.1kJ/g glucose
This is only when the muscles are working aerobically.
For movements such as raising an arm or moving the fingers, adenosine triphosphate (ATP) a chemical form of energy, is used. When the muscles use ATP for energy a chemical process happens where the ATP is broken down into two simpler chemicals, ADP (adenosine di-phosphate and inorganic phosphate. The process of turning ATP into ADP releases the energy which gives your muscles the ability to contract. When exercising ATP is used up within the first twenty seconds, the cells use the ATP in two phases; firstly glycolysis takes place, (the breakdown of glucose to pyruvic acid, which is a form of lactic acid) and then the complete oxidation of pyruvic acid to carbon dioxide and water, which will then be carried away by the blood stream. There may then be a period when the muscles are working an aerobically, without oxygen. A waste substance of aerobic respiration is pyruvic acid; this is then converted into CO. But when anaerobic respiration is taking place the pyruvic acid is oxidised and is converted into lactic acid. The lactic acid would begin to build up from the oxidation of pyruvic acid in muscles. Muscular contractions would become difficult because lactic acid prevents the conversion of energy quickly. If the muscles continued to work an aerobically then muscular cramps would begin until finally they would not work at all. This only occurs when an extended amount of exercise has taken place and in the first few minutes of exercise.
The amount of exercise a person does will affect the pulse rate. For example, more exercise means more movement so more energy will be needed. In order to get more energy; respiration needs to take place at a faster rate. More oxygen is used so more carbon dioxide is produced. Carbon dioxide is a waste product and it must be removed, as it is a toxin. Because of the extra carbon dioxide being produced, blood is pumped around the body faster in order to transport it. This process will give you a faster pulse rate. You will also get cramp if lactic acid is produced due to not enough oxygen being taken in. This is known as respiring an aerobically. This can happen during exercise, when breathing and the circulatory system cannot provide enough oxygen for our muscles to keep going aerobically. Anaerobic respiration is less efficient than aerobic respiration. Oxygen is needed to break down lactic acid to carbon dioxide and water. The amount of oxygen needed to get rid of the lactic acid is called the oxygen debt, which must be paid off immediately. This is why your heart rate stays high and it takes a while to get your breath back after you have stopped running - oxygen is still being delivered to the muscles to oxidise the lactic acid. The fitter you are, the quicker you recover.
Respiration is the process that releases energy from food. Substances from our food is oxidised to give carbon dioxide and water, also energy is transferred. Glucose is the main substance that is oxidised.
Pulse rate represents the beating of the heart, specifically the ejection of blood from the left ventricle to the general circulation of the body. Before the start of exercise, your pre-exercise heart rate usually rises above normal, and this is called an anticipatory response. During exercise, respiration increases based on the amount of activity being done. When exercise is being completed, there is an increased demand for gas exchange, due to the circulatory system being under continuous stress. Oxygen consumption increases rapidly, as well as carbon dioxide production.
Regular exercise also produces changes in circulation. The blood flow to working muscles increase, and this means that more oxygen and energy can be delivered to the muscle cells. Blood volume and the number of red blood cells also increase with this large flow, and oxygen levels rise considerably.
From the above background information I can now clearly see that the level of exercise increases the level of heart rate dramatically.
The above background information was from:-
DICTIONARY-THE A-Z OF HUMAN PSYIOLOGY
INTERNET- GCSE.COM
LEAFLET/MAGAZINE-HEALTH WEEKLY
HUMAN PYSIOLOGY AT GCSE LEVEL-DAVID WRIGHT
METHOD
I will use this method for both the healthy participant and unhealthy participant
- Check pulse rate for 30 seconds then times by two to get the pulse rate for one minute
- Record the pulse rate on a recording table
- Explain what the experiment is about and what the participant is expected to do
- Fill in the details of the participant such as age, weight.
- Tell the participant when the experiment starts and start the stop watch at the same time.
- Stop the experiment after one minute and check the participants pulse rate
- Record pulse rate
- To avoid any cramps or backaches later on after the experiment is completed; lead the participant out of the exercise by telling them to decrease the speed that they are jogging at.
- Wait for the participants pulse rate to return to normal
- Start from the beginning and carry out the experiment again however this time the participant has to jog for two minutes
- Continue the experiment in the same way for five minutes
- Again, lead the participant out of the exercise telling them to jog slower and slower.
Carry out this experiment in the same way but this time using an unhealthy participant.
- Compare results by working out the average of the results and then comparing the results for the healthy person with the unhealthy person and then form graphs to show the differences between the two people.
- Repeat this experiment a second time.
RESULTS
From my results I have found out that the heart rate affects the exercise hugely however it mostly depends on the fitness of the participant too. The first participant was my dad who is not that healthy. He doesn’t exercise regularly. The second participant is my uncle who enjoys walking and exercising and always finds time to go swimming. I have decided to use these two different participants because they are very different from each other and this will help me to get two different results which will be easier to identify bringing in the factor that one participant likes exercising regularly whilst the other doesn’t.
CONCLUSION
From my results I have found out that as the participant exercises more, the heart rate increases dramatically. At the start of the experiment I found it very unusual that participant one who was the unhealthy participant had a much slower heart rate than the healthy participant. The unhealthy participants heart rate increased more than the healthy participants. I found this unusual too. I repeated this experiment a second time due to this unusualness.
EVALUATION
Now that I have done my experiment I can identify any factors that I couldn’t see before the experiment. This experiment couldn’t be a fair experiment because there were many factors that were uncontrolled. Odd results that I wasn’t expecting include a much slower pulse rate for the unhealthy participant rather than the healthy participant.
I also feel that this experiment could have been improved in many other ways such as all the experiment could be done at the same time. This would also help to control any factors such as temperature so there won’t be a major difference in the results. If I were to do this experiment again I would use more participants in the experiment to result in a much wider range of results. I feel that if I was to use more participants then my results would not look unusual and I may also be able to identify a hidden factor due to this.
