What happens During Respiration?
The human body is powered mainly by glucose. This is a sugar you get by digesting starch and other carbohydrates in your food. Before glucose can be respired, it has to be broken down into a simpler substance, pyruvic acid. This travels to the cell’s mitochondria, where it is combined with oxygen to produce carbon dioxide and water. During this process, lots of energy is released. The energy is required for growth, repair, movement and other metabolic activities. Aerobic respiration is exactly the opposite of photosynthesis, which uses energy to make glucose.
Oxygen Debt
When you sprint very quickly, your muscles run out of oxygen. Without oxygen, your muscles cannot turn glucose into water and carbon dioxide. Instead they turn glucose into a substance called lactic acid, which too much of causes painful cramp. This is anaerobic respiration, because it doesn’t use oxygen. The only way to break down the lactic acid is by using oxygen. So as you keep running, the demand for oxygen increases. Later, when you have stopped running, the lactic acid is broken down using oxygen. Some organisms, such as yeast and bacteria, can live entirely by anaerobic respiration.
The Equation
Respiration takes glucose and oxygen and produces energy, carbon dioxide and water. The equation is:
C6H12O6 + 6O2 Energy + 6CO2 + 6H2O.
BLOOD
Why do we Need Blood?
We need blood to transport oxygen and glucose around the body. Our cells take the glucose and oxygen from the blood and use them as energy. Blood is transported around the body by arteries, veins and capillaries.
Prediction
From the information I have gathered for my research, I predict that my pulse rate will increase as my rate of exercise does. In other words, the more exercise that I do, the faster my heart will pump blood around my body, there fore increasing the pulse rate. I think that this is because as my muscles work out, there is an increased demand for oxygen, due to the increased demand for energy. However, there is a limit to how fast your pulse can go (how fast your heart can beat), so at some point, your pulse would reach its limit, and stay at that level. If this was shown on a graph, it would level off (become a horizontal line).
I also predict that the amount of exercise is directly proportional to the pulse rate. I will have to carry out my investigation to see if this hypothesis is correct. This will mean if the amount of exercise doubles, the pulse rate will double, too. This is because the more exercise I do, the more blood the heart will need to pump around the body, and the quicker it will need to do it. This will therefore increase the heartbeat, or pulse rate.
Plan
In order for me to carry out this investigation, I will need to have the apparatus ready and prepared. The apparatus are listed below.
- Exercise machine
- Stop clock
- Trainers
I plan to use the cross trainer machine to exercise on. I will take my pulse first after 1 minute, then 2,3,4, etc. My plan is as follows:
- Go down to the sports hall gym
- Sit down until my pulse rate goes back to normal
- Take my resting pulse rate
- Go on the cross trainer for 1 min
- Take my pulse for 30 secs and multiply by 2
- Wait until my pulse goes back to normal
- Go on the cross trainer for 2 min.
- Repeat steps 5 and 6
- Go on the cross trainer for 3 mins.
- Repeat steps 5 and 6
- Carry on until you have gone up to 5 mins on the cross trainer, still repeating steps 5 and 6 where necessary.
Fair Test
In this experiment, there are a variety of constants. In order to make sure this is a fair test, I will:
- Try to keep my distance per hour at a constant measure- 0.25 Km
- Repeat each experiment 3 times.
- Keep the exercise machine the same throughout.
- Keep the same clothing on- some clothes can restrict movement
- Not eat any food whilst exercising, as this can alter the amount of energy I have in my system
- Take my pulse in the same place, because if I move to take my pulse, I am exercising more, this will make the experiment unfair.
- Wait until your pulse rate goes back to normal before exercising again
The variables of this test are:
Safety
In order to keep the experiment safe, I must do a variety of things:
- Wear trainers, as they provide high ankle support
- Make sure people are well away from the exercise machine, before you begin
- Concentrate on the task, to prevent falling off
- Make sure I know how to use the equipment properly
- Wear appropriate clothing
- Make sure I have eaten and drunk something that day, to make sure I don’t pass out from lack of energy
Results
I will present my results in a variety of ways. First of all I will present them in a table.
My resting pulse rate is 80.
I will now present my results in a line graph.
I will now present my results in a bar chart.
Analysing and Considering the Evidence
All of my results show the same thing, there is a definite relationship between pulse rate and exercise. There is a genuine pattern in my results. My prediction I made earlier was correct, and that was that my pulse rate will increase as my rate of exercise does. In other words, the more exercise that I do, the faster my heart will pump blood around my body, there fore increasing the pulse rate. The reason this happens is because when you start moving at a faster pace the body uses up more oxygen, so therefore the body needs to provide more oxygen to replace it with the increasing carbon dioxide building up in the muscles.
However, during the final minute the pulse rate didn't increase much at all. This happened because as the supply of Oxygen to the muscles decreased, a lot of energy was used up as the exercise took place. The body was then unable to continue aerobic respiration and anaerobic respiration took place. This resulted in lactic acid being formed. This is also because there is a limit to how fast your pulse can go (how fast your heart can beat), so at some point, your pulse will reach its limit, and stay at that level.
I also predicted that the amount of exercise is directly proportional to the pulse rate. This meant if the amount of exercise doubles, the pulse rate will double, too. This prediction is not exactly correct. Both my pulse rate and time increased, but they did not double.
Evaluation
The evidence that I have collected during this experiment is enough to enable a firm conclusion to be drawn. That conclusion is the harder the exercise you do the faster the heartbeats.
Although I believe that my experiment produced fairly valid results, I am not sure that my experiment was particularly accurate. There were some factors beyond my control that could have affected my results. For instance, I cannot be sure that the cross trainer exercise was done at the same rate throughout the experiment. Also, I am not sure that the 30-second intervals were kept exactly to this timing.
If I were doing this experiment again I would have to look closely at the method of exercise I used. I think that exercising on a piece of equipment like a running machine would produce more accurate results because I would be able to guarantee that the exercise remained constant throughout this experiment. To improve my investigation I could have tested more people and compare the fitness. I could also take a skin temperature reading which could tell me if people get hotter or colder doing exercise.
Finally, an actual 'pulse-meter' might have helped the experiment to be more accurate. This is simply strapped round the chest of the exercise and it measures your current pulse rate. I believe that this would produce a more accurate pulse rate and destroyed any necessity to have the 30-second breaks during the exercise.
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