The aim of conducting this experiment is to know the effect of exercise on pulse rate by carrying out few exercises.

Udit Aggarwal

Investigating Pulse Rate

Aim:

Introduction

When exercising or competing in sports, the body undertakes a number of changes. We breathe in heavier and faster, therefore our heart beats faster and our muscles stretch and therefore we sweat. These are all normal responses towards exercises, whether we work out regularly or only once in a while.

To be frank, any type of exercise utilizes the help of the muscles. For example, running, swimming, weightlifting all uses different muscle groups to generate motion. In running and swimming, muscles are working to accelerate the body and keep it moving. In other words, exercise means muscle activity.

In strenuous exercises, almost every system of the body either focuses its efforts on helping the muscles do their work effectively or it shuts down. For example, our heart beats faster during strenuous exercise so that it can pump blood to the muscles, and our stomach shuts down during strenuous exercise so that it does not waste energy that the muscles can use.

When we carry out exercises, our muscles act like Electric Motors. Our muscles take in a source of energy and use it to generate force. An electric motor uses electricity to supply its energy. Our muscles are biochemical (carry’s out vital processes) motors, and they use a chemical called Adenosine Triphosphate (An ester containing three phosphate groups) for their energy source. During the process of "burning", our muscles need three things:

They need oxygen, because of chemical reactions required by Adenosine Triphosphate. They need to get rid of metabolic wastes (carbon dioxide, lactic acid) so that the chemical reactions are generated.

They also need to get rid of heat. Just like an electric motor, a working muscle generates heat that it needs to get rid of.

In order to continue exercising, muscles must continuously make Adenosine Triphosphate. To make this happen, the body must supply oxygen to the muscles and get rid of the waste products and heat. If these requirements are not accomplished, the person conducting the exercise will stop and the body will become exhausted.

Exercise can effect respiration and the heart rate dramatically too. Muscles need energy to maintain their functions. This energy is provided through a process called Respiration.

When the heart is at resting rate oxygenated blood is being pumped around the body for a stable state of aerobic respiration. Resting rates vary between different people. The lower the heart rate of the person, the healthier the person is.

Aerobic respiration is the release of energy from glucose in the presence of oxygen. In our body tissues, glucose can be broken down to release energy, which may be used for bodily functions such as muscle contractions. The general equation for the process of aerobic respiration is:

Glucose + Oxygen = Carbon Dioxide + Water + Energy

Aerobic respiration takes place in all living things. The waste products of this process are Carbon Dioxide, excess water and energy. Carbon Dioxide and water can be easily excreted and the energy is used up in the body where desired.

During the exercise we conduct, the heart rate increases. Aerobic respiration will prolong (lengthen) if the necessary amount of oxygen helps produce enough energy for the muscles to continue functioning.

Anaerobic respiration occurs when muscle cells do not receive enough oxygen to produce the energy ...

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Glucose + Oxygen = Carbon Dioxide + Water + Energy

Anaerobic respiration occurs when muscle cells do not receive enough oxygen to produce the energy needed. This occurs during vigorous (energetic) exercises. The heart cannot pump enough oxygenated blood to the muscles when they become exhausted. The heart rate increases in an attempt to send more oxygen to the muscles, but when it fails anaerobic respiration takes place.

Anaerobic respiration produces less energy than aerobic respiration, although it is only used as a last resort when energy is scarce.

There are more toxic waste products as a result of anaerobic respiration than there are as a result of aerobic respiration. Lactic acid is an organic acid, which is produced as a waste product during anaerobic respiration. Lactic acid is toxic if it remains in the body and it can cause cramps and other muscle pains. Lactic acid can be broken down by oxygen.

When anaerobic respiration starts to take place, energy is taken from glucose without using Oxygen to break it down. This creates an Oxygen debt, which when paid back oxidizes lactic acid to carbon dioxide and water.

Mitochondria are extremely small organelles. Their shape varies from sausage- like to spherical and they can move about in the cells. In respiration molecules of the food such as glucose are broken down to release energy with the aid of oxygen and enzymes. The Mitochondria, therefore, are the main energy converters of the cell. Inside the cell there is a fluid called Matrix and an inner membrane, which folds many times to give maximum surface area?

The matrix is a liquid mixed with water and protein. It is the protein that takes food molecules and then combines with Oxygen. Mitochondrion is the only part of the cell where Oxygen combines with food to release the energy within.

Mitochondrion is an important factor for cell energy. Inside is a cell, in which there can be thousands of mitochondrion’s, depending on the size of the hole inside? The purpose of the mitochondria is to break down food molecules, so that cells have energy to live.

When the heart rate is at its maximum, it is pumping as much oxygen to the muscles as possibly can. After exercise the heart rate will take a while to return back to its resting rate. In this time the oxygen debt is paid back so that any lactic acid is oxidized.

Our blood contains plasma which carries just about everything around our body, but most importantly for respiration oxygen carrying Red Blood Cells (oxygen is carried round the body as oxyhaemoglobin and glucose). When we start exercising our heart, (which pumps the blood around the body) needs to beat faster to get the oxygen and glucose to the muscle cells where it is needed, so that respiration can take place. We then need to breathe at a more rapid rate to provide more oxygen (breathing is the only way to get more oxygen!), so that it can get absorbed into the blood stream and carried to where it’s needed. This is how respiration is linked to pulse rate.

Athletes spend a great deal of time training. It allows their body to adapt its basic response to exercise and to improve athletic performance. Training can:

Make our muscles perform better.
Improve the efficiency of oxygen delivery to the working muscles.
Get the athlete adapted to the competition environment.

Prediction

From previous scientific knowledge, I predict that while carrying out the exercises, the body's temperature, breathing rate and the heart rate will increase. I predict this because when muscles are in use, they produce heat. It is this heat that affects the body's temperature. The body will also try to keep the original heat and will sweat to cool the body down. Muscles need oxygen and glucose to work properly. The formula for respiration tells us that glucose and oxygen are taken in and energy and carbon dioxide are given out. The muscles will need more oxygen and glucose as they work harder, therefore the breathing rate should rise to allow a bigger intake of the two. For this now larger intake the heart must pump this oxygen and glucose, situated in the blood, to the muscle cells more rapidly. This means that the heart rate will increase. The fitter the body, the slower the heart rate and breathing rate will increase. Shown below is cardiovascular system, where the blood travels to and from which part.

Safety

As this experiment did not involve any acids or dangerous chemicals there weren’t many safety issues. But some of the safety issues I shall observe while conducting the experiment are mentioned below-

As I was conducting the experiment in the corridor of the school, I was careful not to break any school equipment lying in the corridor.

I was careful, while I was handling the Pulse Stick 2 as it was a delicate equipment.
Another safety precaution was not do lean by the fire alarm which was behind me while carrying out the experiment.
As, there were 5 other people working in the same corridor, I was careful not carrying out the experiment as the people from my or other group could have got hurt which could have lead to dangerous injuries.

Equipment

Stop Clock – Stop Clock was used to time various stages of the experiment.

Tape Measurer – Tape Measurer was used to measure the distance covered.

Pen and Paper – Pen and Paper were used to record the results.

Pair of Trainers – Trainers were used instead of school shoes, as they can often be painful when running in and this could affect the pace in which the experiment was carried out.

Towel – Towel was used after the practical experiment to wipe off any sweat.

Method

Firstly, I had gathered all the equipment which was to be used while carrying out the experiment.
Secondly, I had set up all the equipment correctly i.e. Made the pulse stick 2 to zero and set up the stop watch correctly so my experiment would lead me to achieve accurate results.
Then, I measured out my own resting heart rate three times in a span of 1 minute 30 seconds, which was equivalent to once in thirty seconds.
After I had measured out my resting heart rate using the Pulse Stick 2, I had taken out the average to make my experiment accurate.
Once the above process had been completed, I decided to record the results after two minutes of each activity.
Between each activity I had decided to wait for a period of five minutes, as I felt this was sufficient time for my heart rate to return to its stationary rate.
I had also decided to conduct all the four activities once a day for three days to make my results accurate.
I had then recorded the recorded the results into a table format.

Fair Test

To keep my experiment a fair test, I needed to keep some of the variables the same each time.

I had made sure that I ran for the specified amount of time and same distance each time. To make sure I don't have any time related mishaps, I had used the same stopwatch used in every activity. I also needed to make sure that I ran at the same pace as I do in every activity. Lastly, I also needed to make sure that I took my pulse for the same amount of time every time in order to make it a fair test.

Average Pulse Rates

Reliability

I had recorded the stationary heart rate three times; which had allowed me to work out an average. Therefore this made the reading more accurate.
I had carried out each activity of exercise for two minutes, which was measured with a stop watch and the results were recorded in a table format.
I had kept the same distance covered same for all the activities except Star Jumps. This will be measured with a tape measurer to ensure reliability.
I had remained at the same pace throughout all the activities, e.g. a change in pace in the jogging will effect my heart rate, so it was necessary that the speed did not change.
I had made sure that I had waited until the heart rate returned to stationary before starting a new activity. I had, as mentioned before, used an five minute break between each activity.

Results*

Firstly I had to time my stationary heart rate; I did this three times and worked out an average as mentioned before:

Day1

Day2

Day3

Final Results

Conclusion

My results agree with my prediction which I had guessed before carrying out the experiment. As I had said in my prediction, as I carry out more exercises my pulse rate increases. From my results too, I can see that, the higher the blood and the oxygen were being pumped faster around my body.

Evaluation

I believe that my experiment was successful and I achieved the results that I had desired. I think I could have made my experiment more accurate and well accomplished by employing people in my group. Overall my results were accurate as I checked them from the people of the other group. I think I had used accurate equipment and there weren’t any strange results I achieved.

While conducting my experiment I think there weren’t any design error but there could have been some human and equipment errors such as:

While I was measuring my pulse rate, I think I had not measured it properly as I was not able to get the Pulse Stick 2 to zero. But at the end I did make it to zero even though, I can’t remember so!
Lastly, I think I measured one of the resting heart rate incorrectly which would have made my experiment inaccurate.

Bibliography

For my research I have used various websites such as:

which lead me to = www.medhelp.org

I have also used: www.mytscstore.com

Lastly, I have used the GNVQ website at home with my own username and password!

* All my results are rounded to 2 significant figures in the Final Results section so that I can represent it on the graph as I am drawing the graph by hand.