Comparing Oxygen Levels to Heart Rate Recovery and Peak Time

Research Question

How do different concentrations of oxygen provided to the respiratory system affect the heart rate and thus a subjects[JB1] athletic capabilities?

Introduction[JB2]

Firstly, it is important to investigate how the body's respiratory system functions. The lungs have two primary functions, releasing carbon dioxide from the body and integrating oxygen into the bloodstream ³. The lungs never reach peak capacity and are not responsible for the limitation in oxygen delivered to the muscles ¹. This is important because, in the case of this experiment the limitations may be reached[JB3]. There is always approximately the same amount of oxygen in the air in relation to everything else: 21%. However[JB4] as altitude increases there is less air pressure and thus less oxygen available to the lungs per diaphragm contraction cycle. Instead of changing the barometric pressure, there will simply be less or more oxygen in the air, in this experiment[JB5]. This may cause an abnormal result as the body responds differently to drastically altered conditions. When the oxygen content of the air is drastically reduced[JB6], the blood will most likely be [JB7]significantly less saturated and when the oxygen content of the air is drastically increased [JB8]the blood should be more saturated with oxygen ².

It is then necessary to investigate how this might affect the cardiac system. The amount of oxygen that is available to the cells while they are producing ATP[JB9] to drive the body is important, because if there is not enough oxygen available for aerobic respiration, than[JB10] anaerobic respiration will take place. Anaerobic respiration will produce lactate and carbon dioxide. The lactate (lactic acid), triggers a response from the sympathetic nervous system^{1, 2}. The noradrenergic sympathetic nervous system produces norepinephrine. The SA node (sinoatrial node), stimulated by the norepinephrine hormone increases both the rate that the heart beats and the degree to which the heart completes a systolic contraction ^1,2. In addition to the sympathetic nervous system, the medulla senses the increase of carbon dioxide in the blood due to anaerobic respiration. The medulla then sends an electrical signal through the cardiac nerve to the SA node².

A live O₂ machine will be used [JB11]in order to [JB12]carry out this experiment. It produces and stores 15% oxygen and 95% oxygen separately. These will be the two concentrations of oxygen that will be used [JB13]to compare the times it takes for heart rates to peak and then recover. The independant[JB14] variable is the concentration of Oxygen. The dependant[JB15] variable is the time it takes for the subject to peak and the time it takes for the subject to recover. The experiment will be controlled [JB16]by regulating the speed at which the treadmill is set [JB17]to. Since the point of this experiment is to compare differences[JB18] the difference in the individual's athletic ability should not make a difference in the data.

Materials

Experimental Overview

The Live O2 machine which will be used [JB19]to create, store and deliver the two different concentrations of oxygen is comprised of an oxygen machine, storage bag with two compartments, a delivery system with a mask and a switch to change which concentration of oxygen is being delivered[JB20].

[JB21]

The picture above, depicting the live[JB22] O2 system is the one that was used[JB23], except a treadmill was used[JB24] instead of a stationary bike as is depicted[JB25]. The test subjects heart rate peak times and recovery times were first tested [JB26]with the increased level of oxygen, they were then given [JB27]a period of rest while another subject ran on the treadmill. Then, after the period of rest the subject would run on the treadmill again and their peak and recovery times would be measured [JB28]with the restricted levels of oxygen. The threshold for the heart rate peaking was 140 bpm[JB29]. The threshold for recovered was when the heart rate of the subject was within 10 of their original resting heart rate. For example, if the test subject's resting heart rate was 65 bpm, they would be considered [JB30]recovered when their heart rate dropped back below 75.

Procedure

Step 1

First 8[JB31] willing people were found[JB32], who were athletically fit [JB33]enough that there would not be any damage to their body through the testing. Then the 8[JB34] people were instructed [JB35]not to drink any sort of caffeine or any other stimulant before the experiment. The mask of the live[JB36] O2 machine was cleaned [JB37]with clorox[JB38] and the oxygen machine was turned [JB39]on to fill up the two individual bags.

Step 2

Then the resting heart rate of the subject was taken [JB40]with the heart rate monitor. Ten was added [JB41]to the resting number to determine the threshold that the heart rate must reach during recovery to determine whether or not [JB42]the subject has 'recovered.' The heart rate monitor was left [JB43]on the subjects[JB44] finger to monitor their heart rate, Then[JB45] the oxygen was se[JB46]t to the 95% setting and the treadmill was set [JB47]to 5 miles per hour. Then, once the subject was at 5 miles per hour the timer was started [JB48][JB49]and the subject was instructed[JB50] to hold the mask to their face. The timer was stopped [JB51][JB52]once the subjects heart rate reached 140 bpm. Then the treadmill was stopped [JB53]and the subject was instructed [JB54]to keep the mask on. Then the time it took for their heart rate to return to the predetermined resting rate was measured[JB55].

Step 3

The first subject was then given [JB56]rest while subject 2 performed step 2. Once subject 2 was done [JB57]with step 2, subject 1 repeated step 2 with 15% oxygen instead of 95% oxygen followed again by subject 2. The mask was cleaned [JB58]with clorox[JB59] between each subject.

Step 4

Steps 1-3 were repeated [JB60]with the remained of the test subjects and the data was recorded [JB61]in a table within the lab book.

Safety considerations

Since this lab works with the human body and measuring its responses to what could be considered[JB62] strenuous situations, there must be precautions taken. Firstly, all of [JB63]the subjects that were tested[JB64], were either in good or exceptional physical condition and had no preexisting health complications that would endanger them during the experiment. To further ensure that there was no physical harm done to the subjects, the subject's saturation was constantly monitored [JB65]with the heart rate/oxygen saturation monitor. If at any point during the 15% oxygen test the saturation dipped too low (below 85% saturation) and remained there for more than a couple seconds[JB66] then the 95% oxygen would immediately been switched on and that round of testing would be terminated and the subject time [JB67]to rest. The mask that was being used [JB68]was also constantly cleaned [JB69]with clorox[JB70] to prevent the spreading of germs.

Analysis

Qualitative variables[JB71]

The two main variables that may have affected the data were: the heart rate monitor and the oxygen mask. The fact that the subject had to hold the monitor on their finger and the mask while running made the heart rate monitor slightly inaccurate and sometimes would simply not take readings. It only worked when the subject was holding onto it and this disrupted their normal running patterns. Some subjects also had trouble holding the mask to their face with enough force to hold a seal while running. This may have let some of the natural air into the mask. Holding the mask also inhibited the subjects natural running pattern. The fact that the subjects natural running pattern was inhibited [JB72]made it harder for them to keep a normal running pace even with the treadmill set at a constant 5 miles per hour. Having to control all of these [JB73]things at once may have also added to the strain on the subject's body, which could have affected the results. Then finally, there is also the fact that everyone that was being tested [JB74]was different in their biological makeup and therefore will respond slightly differently to the two concentrations of oxygen.

Data

Complete Peak and Recovery times (in seconds)

This table displays each run and the times in seconds associated with it. The runs where the higher concentration of oxygen (95%) was used [JB76]are displayed [JB77]first, on the left. The runs where the lower concentration of oxygen (15%) was used [JB78]are displayed [JB79]second, on the right. The peak times (the time it takes for the subjects[JB80] heart rate to reach 140 bpm from resting) are displayed [JB81]in the 2nd and 4th column and the recovery times (the time it takes for a subject's heart rate to go from 140 bpm back to within 10 of resting) are displayed [JB82]in the 3rd and 5th column.

This bar graph displays the average recovery times and peak times for the two different levels of oxygen concentration. The recovery times are listed [JB83]at the top and the peak times are listed [JB84]at the bottom.

Average Difference in Peak and Recovery time in seconds

This table displays the difference between the average peak time of the 95% and 15% oxygen concentration. As well as the difference between the average recovery time of the 95% oxygen and the 15% oxygen concentrations.

Evaluation

Conclusion of results

There is a clear difference between the times for the two different concentration of oxygen. When the subject was administered [JB85]95% oxygen their peak times took an average of 166.75 seconds, while when the average peak time when only 15% oxygen concentration was administered [JB86]was 46.5 seconds. This is a difference of 120.25 seconds, so clearly when a subject is administered [JB87]more oxygen it provides more oxygen for the system, this allows the body to stay out of anaerobic respiration longer and thus allows the heart to beat slower for a greater amount of time.

The difference seen in recovery times was also significant. On average, with the higher 95% oxygen concentration the subjects recovered around 54.875 seconds. However[JB88] when the subjects were administered [JB89]the lower concentration of oxygen the recovery times took much longer, averaging out at 147.75 seconds. The difference was 92.875 seconds. This occurred because when the body was already deprived[JB90] of oxygen and the saturation was low there was a large amount of carbon dioxide and lactic acid build up from anaerobic respiration. Then, after the subject stopped running, the low oxygen concentration most likely caused [JB91]the subjects to stay in anaerobic respiration as the body tried to oxygenate the tissue. With the higher concentration of oxygen, the subjects body was able to [JB92]quickly oxygenate the tissue and return the body to complete or near complete aerobic respiration. This would have stopped the build up[JB93] of lactic acid and carbon dioxide and allowed the body to flush the two out of its system. Once the lactic acid and carbon dioxide has either been absorbed [JB94]or in the case of carbon dioxide, exited the lungs, the heart rate would return to resting.

Therefore, the results matched what should have happened according to [JB95]previous scientific research, outlined in the introduction.

How the lab could be improved [JB96]and extended

The first thing that would be helpful would be to use a more accurate heart rate monitor. Most likely the [JB97]best solution would be a heart rate monitor that could be taped [JB98]to the finger being used [JB99]in unison with a chest heart rate monitor. Using both of these [JB100]simultaneously would ensure the best and most consistent results. In addition[JB101][JB102] it would remove the responsibility from the subject of holding onto the heart rate monitor.

Another issues[JB103] that could be easily solved [JB104]is the oxygen mask. The straps that were provided [JB105]with the mask fell off very easily during running. As a result[JB106] the subjects had to hold the mask to their face as they ran. This hindered their ability to run smoothly and did not guarantee a complete seal around the face. Next time a full head cap could be used [JB107]to ensure that a seal was maintained [JB108]and would allow the subject to run normally.

To further extend this experiment saturation rates could also be compared [JB109]to heart rate and oxygen concentration. When the subjects were performing the test their saturation rates were monitored [JB110]for safety reasons but not recorded. If the saturation rates could be recorded [JB111]throughout the test at specific points along with the heart rate it would be interesting to look into [JB112]how the saturation rates are correlated [JB113]with the heart when very low and very high concentrations of oxygen are being administered [JB114][JB115]to the subject.

Works Cited[JB116]

1. Burton, Deborah Anne, FRCA, Keith Stokes, BSc PhD, and George M. Hall, MBBS PhD DSc FRCA. "Physiological Effects of Exercise." Continuing Education in Anesthesia, Critical Care and Pain. Oxford Journals, n.d. Web. 10 May 2016.
2. Damon, Alan, Randy McGonegal, Patricia Tosto, and William Ward. Higher Level Biology. N.p.: n.p., n.d. Print.
3. "How Your Lungs Work." How Your Lungs Work. Cleveland Clinic, 13 Oct. 2010. Web. 13 May 2016.

Appendix

Release forms: [JB117]

I, Jonas Kaare-Rasmussen understand that the experiment I am involved in and the tasks that I am performing, could be dangerous for my health. I assume all liability for my actions and understand that slight Oxygen deprivation may cause health problems.

Electronically signed by: Jonas Kaare-Rasmussen

I, Jack Larsen understand that the experiment I am involved in and the tasks that I am performing could be dangerous for my health. I assume all liability for my actions and understand that slight Oxygen deprivation may cause health problems.

Electronically signed by: Jack Larsen

I, Danielle Zimber understand that the experiment I am involved in and the tasks that I am performing could be dangerous for my health. I assume all liability for my actions and understand that slight Oxygen deprivation may cause health problems.

Electronically signed by: Danielle Zimber

I, Hailey Zimber understand that the experiment I am involved in and the tasks that I am performing could be dangerous for my health. I assume all liability for my actions and understand that slight Oxygen deprivation may cause health complications.

Electronically signed by: Hailey Zimber

I, Alex Kellam understand that the experiment I am involved in and the tasks that I am performing could be dangerous for my health. I assume all liability for my actions and understand that slight Oxygen deprivation may cause health problems.

Electronically signed by: Alex Kellam

I, Taso Warsa understand that the experiment I am involved in and the tasks that I am performing could be dangerous for my health. I assume all liability for my actions and understand that slight Oxygen deprivation may cause health problems.

Electronically signed by: Taso Warsa

I, Ben Voter understand that the experiment I am involved in and the tasks that I am performing could be dangerous for my health. I assume all liability for my actions and understand that slight Oxygen deprivation may cause health problems.

Electronically signed by: Ben Voter

I, Alex Alsop understand that the experiment I am involved in and the tasks that I am performing could be dangerous for my health. I assume all liability for my actions and understand that slight Oxygen deprivation may cause health problems.

Electronically signed by: Alex Alsop

Conversion from marks to percentage - Pre-lab report

Conversion from marks to percentage - Lab report

OVERALL COMMENTS:

This is an interesting investigation. You proposed a good research question, but you did not make a prediction or hypothesis for your report. It appears implied within the report, but I believe you should list it outright. The paper has large amount of passive voice, if you choose to correct that. The student wrote the report at a grade 11 level, so that is fine. There are some errors in spelling and capitalization, which detract from your report. Good luck in your final submission.

[JB1]Possessive

[JB2]Where is the hypothesis?