Effects of Exercise on Blood Sugar Level and Pulse Rate.

Biology Course Work 1

Topic: Effects of Exercise on Blood Sugar Level and Pulse Rate.

Hypothesis: I hypothesize that during exercise the blood sugar level will rise and the pulse rate will increase.

Background Knowledge:

One of the most important metabolites in the blood is glucose. Its level must be controlled strictly. Glucose is the main respiratory substrate and must be supplied continuously to cells. The brain cells are especially dependant on glucose and are unable to use any other metabolites as an energy source. Lack of glucose results in fainting.

The normal glucose level in the blood is 90 mg per 100 cm3 blood, but may vary from 70 mg per 100 cm3 blood during fasting up to 150 mg per 100 cm3 blood following a meal.

During exercise, the rate of respiration will increase because the body has to break down more of sugar store in presence of oxygen to carbon dioxide and water to produce energy.

The following equation is a summary of the reaction:

C6H12O6 + 6O2 → 6CO2 + 6H2O + 38 ATPs

Effects of Exercise on Body’s Metabolic Processes and Hormone Production:

Respiration is a process by which the body uses sugar for energy. Carbohydrates, one of the three principal constituents of food, form the bulk of the average human diet. The end product of the digestion and assimilation of all forms of carbohydrate is a simple sugar, glucose, commonly called grape sugar when found in food, or blood sugar when found in the human body. The metabolism of fats and of certain protein substances also sometimes leads to the production of glucose. Glucose is the principal fuel that the muscles and other portions of the body consume to produce energy. It is present in every cell and almost every fluid of the body and maintaining its concentration are among the most important processes in human physiology.

During exercise the body needs more amount of oxygen and glucose for respiration. The endocrine glands release hormones that increase heart beat and respiration , elevate blood sugar level , increase prespiration , dilate the pupils and slow down digestion because the digestion process consumes a lot of energy which is needed by the body during exercise.

One of the main hormones secerted during exercise by the endocrine glands namely Adrenal Gland is Adrenaline. Adrenaline is not necessary for the maintainence of life and is normally present in the blood in minute quantities. In times of exertion, however, large additional quantities are secreted, exerting a marked effect on the body structures in preparation for physical exertion. It stimulates the heart, constricts the small blood vessels, raises blood pressure, liberates sugar stored in the liver and relaxes certain involuntary muscles while contracting others.

The following table shows the effect of hormone Adrenaline and the purpose of its response in the case of exercise.

When the glucose level in the blood falls during exercise more glucose is formed by the action of another hormone called Glucagon. The pancreas produces glucagon. Its function is to help maintain a normal blood-sugar level. As opposed to insulin, which is a hormone that serves to lower the level of glucose in the blood, Glucagon raises this sugar level by stimulating the breakdown of the compound glycogen into the glucose units of which it consists. The hormone also stimulates the production of glucose from amino acids. This hormone is mainly considered with the breaking down of glycogen to glucose in the liver and has to reaches all parts of the body and serves the requirement of increased glucose levels.

Effects of Exercise on Blood Circulation :

During exercise the body also requires a good supply of oxygenated blood as well. All this is achieved by increasing the cardiac output and by pumping propotionately more of the body’s blood to the muscles. Even the anticipation of exercise increases the stroke volume and heart rate at full speed. A sprinter’s heart may beat more than 200 times per minute. The pulse rate increase during exercise is related to the higher heart beat rate. When blood enters the arteries at the moment of ventricular contraction, the blood streches the walls of the arteries. During diastole, the distended arteries return to their normal diameter, in part because of the elasticity of connective tissue and in part because of the contraction of muscles in the arterial walls. This return to normal is imporatnt in maintaining a continuous flow of blood through the capillaries during the period while the heart is at rest. The expansion and contraction of the arterial walls that can be felt in all the arteries near the surface of the skin is called pulse.

The heart rate remains high for a while after exercise.

During exercise the skeleton muscles recieve propotionately more of the body’s blood by a process of shunting. By dilating the blood vessles in one part of the body and constricting those in other parts , blood is diverting to active muscles from for eg: the intestine. This is one reason why it is unwise to exercise after a big meal. Whereas the blood suppl to intestines and skeleton’s muscles varies with level of exercise, the blood supply to the vital organs , especially the brain , heart & ...

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The heart rate remains high for a while after exercise.

When blood reaches muscle tissue, maximum amount of oxygen is given out by the blood & carbon dioxide excerted by the respiring cells causes haemoglobin to release more oxygen because of the Bohr Effect. The high temperature in and around very active muscles cause even more oxygen to be unloaded ( oxygen dissociation increases with temperature) at high workloads; muscle is able to contract a much higher percentage of oxygen from blood than at low workloads.

Effects of Exercise on respiration, breathing and gaseous exchange :

Exercise entails muscular movements and hence the need for an adequate supply of oxygen to release energy required for the contraction of muscle fibres. To increase the oxygen supply , the rate of gas exchange at the lungs must be increased. This is achieved by increasing the number of breaths per minute from an average of 15 at rest to 45 at the peak of strenuous exercise. With fitness training , the normally passive and relatively slow process of expiration is accelerated because both the internal intercoastal muscles and abdominal muscles contract forcefully to pull the ribs inwards and the diaphragm upwards. This results in a much more rapid expulsion of air than occurs in an unfit individual, thus allowing , more breaths to be taken in a given period of time. To ensure continual removal of carbon dioxide from the body & entry of oxygen into the body to meet the needs of increased level of respiration, the ventilation process increases. This is generally an increase in breathing rate. Oxygen concentration also has an effect on breathing rate.

During exhausting exercise lasting a few minutes, the rate of breathing may rise to more than 30 breaths per minute or more than 30 breaths per minute and ventilation of the lungs may exceed 120 dm3 per minute. All the respiratory muscles, the internal & external intercoastal muscles and the diaphragm, work as hard as they can to draw in and out of the lungs a substantial proportion of the energy produced by the cellular respiration is used in these ventilatory movements.

At the end of the vigourous exercise, the sprinter breaths much more quickly and deeply and consumes more oxygen than normal. This process is commonly refered to as paying off oxygen debt.

I decided to investigate the effects of exercise on blood sugar level and pulse rate. I will be using all the above-mentioned information to relate the two factors and prove my hypothesis.

Planning:

Apparatus:

Glucometer – for checking of blood sugar level
Pulse monitor – for checking pulse rate
Stop watch – to record time period of exercise.
Sterilized Gauze with Cleansing Alcohol – to clean finger before and after pricking.
Bandages – to put around finger after the prick.
Digital Weighing Machine- to obtain the weight of each volunteer.

Risk assesments:

I will wear gloves before starting my investigation to ensure my safety and avoid contamination of the apparatus.

The sterilised needle I am planning to use is only opened at the time it is to be used to ensure it is not kept in contact with air for too long, this could contaminate it and prove hazardous for the volunteer.

I will use a new needle for every blood sugar check.

After the experiment is carried out; I will make sure all the used apparatus which includes cotton ball with alcohol, needle, strip and gauze is diposed off carefully.

While wrapping the machine around the volunteer’s hand I ensure it is not too tighly tied because this could injure the volunteer.

I will carry out my experiment under a Doctor’s Guidance.

Safety Precautions:

While checking the volunteer’s weight , shoes will be removed to give accurate reading.

The finger of volunteer may be contaminated so I will use an alcohol swab to wipe the finger before pricking it.

I will allow the alcohol to dry before pricking the finger otherwise alcohol may get mixed with blood and may affect the final reading.

I will choose my volunteers carefully. I will ensure they are healthy and comfortable while pricking their finger to avoid any calamity eg:- fainting and I will obtain parent’s permission as well.

After exercise the pulse rate is checked immediately to avoid any errors beacuse the pulse rate can get back to normal.

I will carry out the investigation on the volunteers , one at a time, because if it is done all together, some time maybe wasted while checking blood sugar level and pulse rate, this could lead to erroneous results.

I will give all my subjects a particular exercise to do within a particular amount of time this will prevent any variation in my results.

I would make sure the volunteer I pick out is non-diabetic.

Outline Method:

In this investigation, I have planned to take 10 volunteers and check their blood sugar level and pulse rate, before and after exercise. I will also take into consideration their weight . I will keep their age factor constant. I have taken 10 volunteers because I will be able to obtain a range of different values, which will support and will be helpful in proving my hypothesis. I will make it a fair test by using the same subject throughout the whole experiment. The volunteers will be doing the same exercise, which is jogging around the football field for the same period of time, which I have decided, would be 10 minutes.

First I will wear gloves. Then I will line up the volunteers and will check their weight using the weighing machine, I will record the derived readings in a table. Next I will dip a cotton ball in alcohol. Then I will carry out the following steps to check the blood sugar level

Step 1- Clean the finger tip of the volunteer with an alcohol swab. Preferably left ring finger tip. Wait for one minute for alcohol to dry otherwise alcohol may get mixed with blood and will effect my reading.

Step2 – Load the laucet with the needle and keep ready by pulling the sliding knob backwards. Insert a strip into the glucometer onto which the blood drop has to be put.

Step3- Place the laucet on the finger tip and press finger tip a little to ensure more blood flow. Then I will press the button which will release the needle to prick the finger

Step4- As the blood drop appears on the finger tip ( gently squeeze the finger tip once again ) and bring the finger tip onto the strip which has already been placed or inserted in the glucometer.

Step5- When the blood drop is put on the strip, a blood drop sign begins to bink on the screen.

Step6- While waiting for the results I will simultaneously wipe the finger with the sterilized gauze and put a bandage around the finger.

Step7- I will dipose all the used apparatus which includes cotton ball with alcohol, needle, strip and gauze.

Step8- I will read the results after the blinking stops. This result will be recorded in a table.

Then I will carry out the following steps when checking the pulse rate using pulse monitor.

Step 1- The pulse monitor is wrapped around the left wrist ( not too tightly).

Step 2- The pulse monitor is switched on and allowed to inflate.

Step 3- The volunteer is kept in a very quite surrouding to avoid any effects on pulse rate, at the end of several blinkings; a particular reading is reached.

Step 4- I will record this reading of pulse.

After this I will send the volunteer to jog around the field. I will simultaneously start the stopwatch. After 10 minutes I will call the volunteer back from the field and without much time delay, I will carry out the same steps as mentioned before to check the pulse rate and blood sugar. I will follow the same procedure for all the 10 volunteers separately. I will record my new results in the table.

This is a format of the table I plan to use.

Prediction:

After exercise I expect the volunteer’s blood sugar level to increase due to increased energy requirements and I also expect the pulse rate to increase due to increase in heart pumping rate.

Variables:

-The type of food consumed before exercise could vary from volunteer to volunteer would cause a slight diffrence in results.

-Some volunteers maybe be regular exercisers while other may not , this could cause variations in the result.

-Height and Weight are factors that have to be controlled.

-Age and Sex of the individual are two other factors that could influence the effect of exercise on rate of breathing and pulse rate.

I have therefore chosen volunteers of the same age group, 15, and they are all boys. I also made sure that they had all consumed their meal one hour before exercise but I could not control factors of weight, height and the type of food they consumed.

Implementation:

Method:

Just as I had planned, I took 10 healthy volunteers. I wore my gloves before I started the experiment.

I lined up all the volunteers and weighed them using the digital weighing machine. I recorded my results in the weight column of the table.

Then for each volunteer I carried out the following steps to check the volunteer’s blood sugar level. I dipped a cotton ball in alcohol.

Step 1- I cleaned the finger tip of volunteer with an alcohol swab. I chose the left ring finger tip. I waited for about one minute for the alcohol to dry

Step2 – I loaded the laucet with the needle and kept it ready by pulling the sliding knob backwards. I then inserted a strip into the glucometer onto which I was supposed to put the blood drop

Step3- I placed the laucet on the finger tip of the volunteer and pressed the finger tip a little to ensure more blood flow. Then I pressed the button which released the needle to prick the finger

Step4- As the blood drop appeared on the finger tip. I gently squeezed the finger tip once again and brought the finger tip into contact with the strip which has already been placed or inserted in the glucometer.

Step5- When the blood drop was put on the strip, a blood drop sign appeared and began to blink

Step6- While waiting for the results I simultaneously wiped the finger with the sterilized gauze and put a bandage around the finger.

Step7- When the reading appeared on the screen, I recorded it in the column of blood sugar before exercise.

Step8- I carefully diposed all the used apparatus which included cotton ball with alcohol, needle, strip, gauze and a few other plastic wrappings.

Then I started testing the volunteer’s pulse rate using the pulse monitor. I carried out the following steps:

Step 1- I wrapped the machine around the left wrist of the volunteer

Step 2- I swtiched on the machine and allowed it to inflate.

Step 3- I made sure that the subject was calm so that my reading would be accurate. Then after several blinkings on the screen a reading appeared.

Step 4- I recorded this reading in the column of pulse rate before exercise.

Then I allowed the volunteer to start jogging around the field while I simultaneously started the stopwatch. I waited for 10 minutes. When the watch reached the 10-minute mark, I asked the volunteer to stop exercising and without wasting much time, checked the pulse rate and blood sugar level. I carried out the same steps as before to obtain both the readings and I recorded the pulse rate reading in the pulse rate column after exercise while I recorded the blood sugar level reading in the blood sugar level column after exercise. I followed the same procedure for all the 10 volunteers separately and recorded their results in the table.

Results:

Analysis:

Table 1: Pulse Rate

Explanation of Table 1-

In Table 1, we can see that volunteers H and I have had a 50% increase in their pulse rate which is the highest among recorded values. Volunteers A, C, D, and E are next to follow. They fall between a range of 25% to 35% and the lowest among my recorded values are those of B, F, G and J. The percentage increase in their pulse rate falls between 15% to 25%.

All the volunteers have experienced an increase in pulse rate. This means that their heart beat rate was increased greatly to supply blood faster to parts of the body, which need it either for the supply of oxygen and glucose or for the continual removal of waste materials and carbon dioxide.

Table 2 : Blood Sugar Level

In Table 2, we can see that volunteer A, B and H experience a percentage decrease in blood sugar level. Volunteers C, E anf F have the highest recorded values of percentage increase in blood sugar level while the rest of the volunteer’s blood sugar level falls within the range of 1% to 15%.

The volunteers A, B and H experience a percentage decrease in blood sugar level because they could have been regular exercisers so their body can function and carry out the respiration processes extremely fast without breaking down extra amounts of glucose therefor they donot show an increase in blood sugar level whereas there has been a decrease because blood sugar already present in their bodies at the time of exercise is being utilised.

The rest of the volunteers have an increase in blood sugar level because their body is breaking down glycogen to glucose to meet with the high energy requirements of the body during exercise.

As in the case of Blood sugar level graph, on an average there has been an increase in value of blood sugar level after exercise when compared to values of blood sugar level before exercise.

The only exceptional cases where this has not occurred is in the cases of A, B and H.

One of the main reasons this variation occurs is due to the fact that these three volunteers could have been regular exercisers, so their body is accustomed to the increased requirements of blood sugar for energy purpose. Their body will be able to produce energy by using up all the glucose present in their blood at that instant rather than producing hormone glycogen to convert glycogen store to glucose. The sugar already present in the blood has to be carried to the various parts of the body for respiration to occur; therefore their heart beats faster to pump the blood to different parts of the body. Another reason for faster heart beat is to ensure faster removal of carbon dioxide from the blood and faster diffusion of oxygen into it. The other volunteers maybe occasional exercisers, so when exposed to jogging for a period of time, their body produce more of the hormone glucagon, to convert stored glycogen to glucose, since their bodies are not used to frequent high energy requirements.

Explanation of Pulse rate graph-

Looking at the pulse rate graph, we can clearly see that the value of pulse rate after exercise has increased when compared to the value of pulse rate before exercise. Pulse rate increases because the heart is beating at a faster rate so that blood flows faster for two purposes: One is to ensure carbon dioxide is removed at a fast rate from the blood and oxygen diffuses at a faster rate into blood. Secondly, is to carry the sugar to all parts of the body especially the muscles functioning during exercise so that respiration process occurs for energy production. The blood has to move to the different parts of the body at a faster rate especially during exercise to meet with the increased breathing rate and respiration process. The volunteers A, G and H have the highest pulse rate as seen in the bar chart possibly because they are regular exercisers so therefore their body was breaking down sugar at a much faster rate therefore rising the need of oxygen and increasing the amount of carbon dioxide to be removed. The sugar has to be carried to the muscles at a faster rate as well.

I would conclude that on an average blood sugar level and pulse rate increases after exercise because as it can be seen in the result of most of the volunteers, the values of blood sugar level after exercise has increased while pulse rate level after exercise has increased for all volunteers. Blood sugar level increases to provide enough sugar for the respiration process which in turn provides energy to exercise while pulse rate increase shows that the heart beat rate was fast because the blood has to be pumped to the muscles and back to the heart at a very fast rate. Both these changes occur under the influence of the hormone Adrenaline, which is secreted by the Adrenal Gland. When the subject begins to exercise the body produces adrenaline, which brings about different changes in the body to ensure the muscles can meet with the increased energy requirements during vigorous exercise.

One of the main effects is the production of Glucagon, which converts Glycogen stored in the liver to glucose. During exercise the body also requires a good supply of oxygenated blood as well. All this is achieved by increasing the cardiac output and by pumping propotionately more of the body’s blood to the muscles so this explains why the pulse rate is increased during exercise.

So when taking into consideration the overall results I would say that this investigation thus proves my hypothesis right.

Evaluation:

Reliability:

In spite of the few drawbacks in my experiment, I would consider my investigation reliable enough to prove my hypothesis right because most of the readings I have taken have met my expectations.

The blood sugar level of the most volunteers did rise after exercise because their body was breaking down glycogen to glucose to provide sufficient sugar for the respiration process to provide energy for the volunteer during exercise.

Volunteers A, B, H have shown anomalous results because they have been regular exercisers so their body has adapted to frequent exercising and the changes that occur during exercise. Since they exercise on a regular basis their body can use up all the sugar present in the blood at the time of exercise to provide energy so we do not see an increase in blood sugar level instead we see a fall in the level due to use up of sugar present in the blood whereas in the case of others since they exercise once in a while it takes time for their body to adjust and therefore more glucose is broken down in the process therefore rising their blood sugar level.

Another factor that could have resulted in this inconsistency is the kind of foods the volunteer has taken in before the experiment. Some volunteers could have had a carbohydrate rich diet while the others could have had protein-rich or fat-rich diet.

Yet, I had expected the blood sugar level and pulse rate to increase after exercise, and in most cases, for almost all the volunteers my expectation matched the results. By taking a large number of volunteers I have been able to investigate more number of factors that affect the blood sugar level and pulse rate after exercise. We have been able to record finer details and find explanations for the anomalous results.

I have made a few errors which could have been avoided at the beginning of the experiment, these errors I have summarized in the following:

I did not separate the volunteers into different categories.
I did not allow the volunteers to exercise for enough time.
I did not take into account the kind of food substance consumed by the volunteer before exercise.

Variability:

In my investigation I had not taken into account a few variables like:

Whether the volunteer exercised regularly or not
The type of food the volunteer took in before the experiment.
All volunteers were of varying weight and height values.

These factors could have affected my investigation because when the volunteer exercises regularly, as mentioned before his body gets accustomed to the increased energy requirements, so it can basically produce more movement at a lesser energy value, as the person develops more stamina. The heart can function at a faster rate without being under much pressure. So blood sugar level shows little or no increase for these regular exercisers.

In fact as seen in this investigation there can be a decrease in value of blood sugar after exercise, possibly because the body has used up and is in the process of using up all glucose present in the blood at that instant.

Another factor that could be the reason for this variation is the food intake of the volunteers before exercise. Some volunteers may have had a high-sugar diet before exercising, so when tested before exercise blood sugar level is already high in the body. After exercising, most of the sugar content would be used up for energy, therefore when blood sugar level is tested after exercise, we can see a decrease.

Lastly weight and height are the two other variables that should have been controlled because every body produces energy according to the body’s requirements. A taller body with high mass needs more energy to exercise than shorter body with lower mass.

Limitations:

When controlling the food intake of the volunteer it is not possible to take into consideration the typical kinds of food they are consuming.

While exercising, is it difficult to make sure that all volunteers exercise at the same capacity because some volunteers may have greater stamina than others.

Steps to Improve:

I would increase the number of volunteers so that I can have a still wider range of values.

I would categorize the volunteers into different categories. For e.g.: volunteers who are regular exercisers in one category while volunteers who are occasional exercisers in another while those who seldom exercise I will include in the last category