The matrix is a liquid mixed with water and protein. It is the proteins that take food molecules and combine then with Oxygen. Mitochondria are the only parts of a cell where Oxygen combines with food to release the energy within. In cells aerobic respiration takes place in the mitochondria.
When the heart rate is at it’s maximum it is pumping as much oxygen to the muscles as possible. After exercise the heart rate will take a while to return back to it’s resting rate. In this time the oxygen debt is paid back so that any lactic acid is oxidised.
Introduction and Predictions
I am conducting an investigation on the effect of exercise on the heart rate. My research, experiment, results and the entire investigation will determine how different factors of exercise can influence our hearts. Several of these factors include respiration, oxygen, glucose, energy, muscles and lactic acid.
The experiment shall last for five days. Once every 24 hours a vigorous 15 minutes of exercise will take place. The pulse will then be taken once every minute after exercise. The findings will then be compared and a full conclusion and evaluation will follow.
Using the correct equipment in my experiment, I have several predictions as to what will happen. I believe that my heart rate will increase during exercise because my muscles will get increasingly tired and require more Oxygen to create energy. This will result in faster breathing and aerobic respiration may stop while anaerobic respiration begins.
If the exercise sessions continue to test the durability of my muscles then my muscle cells will stop accepting Oxygen and will take energy from partially broken-down glucose. This should cause an Oxygen debt and lactic acid will be the waste product produced.
I expect the heart rate will slowly decrease after exercise and return to resting rate. This is because the Oxygen debt needs to be paid back to dispose of the lactic acid. Oxygen in the blood will do this and less will be needed as more of the lactic acid is broken down.
When the heart rate finally returns to resting rate I will know that all the lactic acid has been broken down, anaerobic respiration will be over, and the muscles will be getting enough energy from aerobic respiration to function normally.
Hopefully my investigation and results of the experiment will prove my theories to be correct.
Plan of the Experiment
When fully relaxed measure the heart rate for fifteen seconds and multiply by four. Keep documentation of your result. Repeat this process a further two times. Add all the results together and divide by three. Record the outcome. The outcome is the hearts average resting rate in beats per minute (BPM).
Decide upon a suitable form of exercise for the experiment. It should make the heart beat fast and allow anaerobic respiration to take course after an exercise session of 15 minutes. The chosen form of exercise should be practical and conform to the same routine every twenty-four hours for five days.
Before each exercise session measure the heart rate for fifteen seconds and then multiply by four. The result is the current heart rate in BPM. Refer to the recorded resting rate and ensure that it is equal to the current heart rate. If it is higher then take in deep breathes and relax for an extra two minutes. If the current heart rate matches your recorded resting rate then the hearts condition shows it is prepared for exercise.
Make certain that all other conditions are appropriate for exercise. The subject must not be ill, tired, hungry or thirsty. It is important to eat before exercise so that the mitochondria in the muscle cells can gain energy from food molecules. The only factor that should affect the heart rate must be exercise.
Before each exercise session also ensure that any apparatus used throughout the experiment is working efficiently and more importantly, safely.
Begin the session of exercise and maintain fluent and steady exercise. Continue exercising for fifteen minutes without stopping. The heart should now be beating fast and lactic acid may have developed from anaerobic respiration.
At the end of each exercise session no fluids or food of any kind should be swallowed. All attention must now be paid on the heart rate. No movement, communication or function of any kind should take place.
As soon as exercise stops the heart rate must be measured. Count the hearts beats for 15 seconds and then multiply them by four. Record your result in the units BPM (beats per minute). Repeat this procedure for measuring the heart rate for 15 minutes after exercise, recording each result.
To increase the accuracy of the conclusion of the entire experiment is, it should be repeated. Have an exercise session every twenty-four hours over the course of five days. Recording the results of each session is essential.
The routine before, during and after each exercise session should be identical to the previous session. It is vital that each exercise session is carried out with safety precautions, precision and a great deal of care.
Evaluation
Overall the entire experiment was a big success. But several small problems presented themselves, posing a slight threat to the accuracy of my results.
I used an exercise bike for apparatus in the investigation and on the second day of the experiment I made a foolish mistake. I never took the necessary precautions to make sure the bike was safe and working efficiently. I paid for this mistake when I was five minutes into the exercise session when the pedals on the bike suddenly broke and became detached from the bike. This interfered with the session as it was supposed to be a fluent fifteen minutes of exercise.
I soon fixed the problem by changing the faulty screws that were holding the pedals to the bike. Soon after I was ready to cycle again and I did so for another session of fifteen minutes.
This small mistake seemed to affect the results slightly. Comparing all the results I noticed that after two minutes of exercise on all the days, apart from the second day, there was a maximum of twelve beats per minute between them. But there are a maximum of twenty-eight beats per minute separating the results of two minutes after exercise on the second day from two minutes after exercise on all the other days.
This anomalous result was ignored on the graph and did not affect the line of best fit in any way.
An irregular heart pattern also emerged on the fourth day of the experiment. Eight minutes after exercise my heart beat increased by 4 BPM instead of decreasing. Over the next two minutes it decreased but on the eleventh minute after exercise it increased yet again by 4 BPM. This strange activity cannot be accounted for. The most likely reason for it is that I wasn’t breathing in enough Oxygen. So the heart may have felt it had to beat more Oxygenated blood to my muscles and lactic acid.
Apart from these two small mishaps all the other results appeared to be standard. The line of best fit on my graph of results supports my research and predictions because it shows the decrease in my heart rate after exercise as the Oxygen debt caused by anaerobic respiration is gradually paid back.
If I conducted the experiment again then I would make several slight improvements to make my results even more accurate.
I would always test out my apparatus before using it for an exercise session to ensure its safety is at maximum.
I would also use more reliable apparatus. Instead of using a standard exercise bike I would use one that could digitally calculate the speed and distance I travel on it. That way I could consult the speed to make certain I maintain the same speed throughout each exercise session. It would also help with my conclusion and give opportunities for other graphs because I would be able to include details of the relationship between the distance travelled and the heart rate.
The only other improvement I would make to the experiment would be to carry out exercise sessions in an isolated location. That way no people or noise could affect my heart rate.
The complete investigation has proved to be a big success. My results support my research and they are suitable evidence to accompany my theories.
Conclusions
After drawing up a graph from my table of results I can now conclude my investigation with observations. My results can be used as scientific evidence to prove my theories are correct.
My results show that my heart rate was between 152-172 BPM straight after each exercise session had ended. The line of best-fit shows that the average heart rate straight after exercise sessions was 160 BPM. These examples show my heart rate was quite high after exercise. This is because my muscles were tired and needed energy and there was a lot of lactic acid that needed to be broken down. Therefore, my heart pumped as much oxygenated blood as necessary to my muscles, for energy, and lactic acid, to be broken down into Carbon Dioxide and water.
Anaerobic respiration is a method that uses energy improperly. To completely break down glucose into useful energy it must be in the presence of Oxygen. But anaerobic respiration doesn’t offer that oxygen. So an oxygen debt is created. The waste product of anaerobic respiration is lactic acid. This toxic product can cause pain among muscles and is not as easy to dispose of as Carbon Dioxide and water. So the heart beats fast to pump a lot of Oxygen to the lactic acid to break it down. The lactic acid is then broken down into Carbon Dioxide and water, the waste products of aerobic respiration.
There is a very steep drop in the line of best fit on my graph between 0-1 minutes after exercise. This was when the heart rate was beating fastest. The heart rate beat fast immediately after exercise, sending a lot of Oxygen to my tired muscles and lactic acid that was produced as a result of anaerobic respiration. This produces a lot of energy for my muscles and broke down a lot of lactic acid. So the minute after the heart was beating at a maximum of 172 BPM it could be reduced to a minimum of 100 BPM simply because such a large amount of Oxygen wasn’t required anymore.
After each session of exercise it was required that we undergo a measuring process of the heart rate for fifteen minutes. Comparing all five days of the experiment, half way through the measuring process my heart rate was at a minimum of 84 BPM, my resting rate. The maximum was 92 BPM. The average within the five-day experiment was 90 BPM.
Some days after exercise my heart rate would be higher than my resting rate but it didn’t decrease over time; it stayed the same for several minutes. For instance, on the fourth day, after exercising, my heart remained at 88 BPM for three whole minutes. This could be because during that time I wasn’t breathing in enough Oxygen to continue the effective break down of my lactic acid. Or maybe it was because the same amount of Oxygen was required to work on breaking down the lactic acid for three minutes.
My heart always resumed resting rate within fifteen minutes after exercise. The least amount of time my heart took to reach my resting rate, at 84 BPM, was eight minutes, on third day of the experiment. The average time for my heart to reach resting rate after exercise was eleven minutes. If I were healthier then not only would my resting rate have been lower than 84 BPM, but my heart would take less time to reach resting rate after exercise.
Straight after my exercise sessions my muscles always seemed to feel fatigued, this was because of the lactic acid build up in my muscles. But given a fifteen-minute period of Oxygen supply the pain disappeared, as did the lactic acid.
