Human Physiology Practical - Phuong Nguyen

Exploration: Research Question: What effects does exercise intensity, indicated by various running distances at 10m, 25m, 50m, 75m, 100m, have on heart rate in comparison to the resting rate at 0m? Background Information: The circulatory system involves 4 major components consisting of the heart, arteries, veins and capillaries. These establish a very efficient pipe network that delivers blood and other vital substances to the body’s tissues. The heart is a hollow muscular organ that consistently pumps blood throughout the entire human body, whereas arteries, veins and capillaries are blood vessels required for the transport oxygen, nutrients and waste products around the body. This system known as the ‘circulatory system’ is crucial for bodily functions as it is responsible for transporting different substances such as oxygen and nutrients between body cells, as well as managing bodily waste materials. Along with the cardiovascular system – a part of the larger circulatory system – it also aids in fighting diseases, maintaining normal body temperature, and providing the necessary chemical balance for homeostasis. The heart is a specialized organ with cardiac muscle responsible for pumping blood throughout the body via the blood vessels as mentioned above. There is a group of specialized muscle cells located in the right atrium of the heart, which controls the heart rate. Heart rate is the measurement of the speed in which the heart beats or contracts per unit of time (minutes) in the different chambers of the heart. The heart rate essentially reflects on how rapidly the heart is pumping blood throughout the body to fulfill physical bodily functions. The lower heart rate – number of heartbeats per minute – the more efficient the heart functions. This may also indicate better physical health of an individual. A normal resting heart rate for adults ranges from 60 to 100 beats per minute. Factors capable of influencing the heart rate may include temperature, medication, body position, physical exercise etc. In this particular experiment, the effects of exercise intensity on heart rate will be tested, observed and explored. Exercise uses up a large amount of energy in the body, which the cells derive from oxidizing glucose for aerobic respiration. It is represented by the following equation: C6H12O6+ 6O2  6CO2 + 6H2O + energy During exercise, the muscles produce more energy. Thus, the circulatory system enhances the supply of fluids, oxygen and nutrients that the muscles need for energy production to respond to the body’s physical demand. The heart rate also increases during exercise, which is indicated by the pulse rate. When exercising, the arteries expand each time the ventricles pump blood out of the heart. As a result, the heart speeds up to pump oxygen and necessary materials to the muscles for exercise, increasing the blood flow and the heart rate. Independent Variable: Independent variables are variables that are changed or controlled in an experiment to test for its effects on the dependent variable. In this scientific practical, the independent variables include the distance ran (measured in meters). Dependent Variable: A dependent variable is the variable being tested and measured in an experiment, which is the heart rate, indicated by the carotid pulse of the individuals performing the exercise (bpm – beats per minute). Controlled Variables: A controlled variable is a variable that remains constant throughout the entire experiment. Controlled variables can significantly influence the results; it is held constant to examine the effect of the independent variable. The controlled variables in this experiment are: Running Surface Grass on the football oval Performing the experiment on different surfaces with different friction and resistance may affect the results obtained. Since the objective of the practical is to observe the effect of exercise, the running surface will be kept constant to prevent errors. Footwear No shoes with socks If the participants are running with a variety of footwear, this can affect the results as the varying resistance offered will influence the participants’ ability to run, thus influencing their heart rate. For this reason, the participants will be running in their socks without any footwear. Stopwatch The same stopwatch The same stopwatch is used as different stopwatches have different calibre, which could introduce error into the experiment. Participants Two participants doing five trials of each of the six distances The same participants will be used to perform this experiment. This is because each individual have different physical health statuses that causes their heart function to be either efficient or inefficient. Alternating between different participants will introduce random errors into the experiment; hence, the same participants will be running the distances. Uncontrolled Variables: The uncontrolled variables are variables that cannot be kept under control. Air temperature and humidity Air temperature and humidity tends to fluctuate and can affect the heart rate of individuals participating in this experiment (outdoor) by either increasing or decreasing it. This is a variable that cannot be controlled. The participants’ emotions Emotions are capable of affecting the experimental results regarding the heart rate. Emotions such as stress and anxiety are capable of causing the heart rate to increase. The participant’s emotions cannot be controlled and could affect the experiment. Running speed The greater the running speed the more intense the exercise. This experiment solely focuses on the effect of running various distances on the heart rate thus; running speed will be an uncontrolled variable that may affect the heart rate. Materials: 1x stopwatch 1x 50m measuring tape 1x football oval Methodology: Unravelling and laying the measuring tape in a straight line on the football oval marked out a 50-metre line. Using the stopwatch to measure the time, the participants placed their index and middle fingers over the carotid artery in their necks for thirty seconds and counted the number of pulses they felt. This number was then recorded, and the step was repeated four times. The participants removed their shoes but kept their socks on. Starting at the same time and at approximately the same speed, the two participants ran 10 metres and then stopped. The time taken by the participants to run the distance was recorded and their pulses were then measured in a similar manner as to step 2. The participants rested for approximately 1-2 minutes until their resting pulse was reached. Steps 4 and 5 were then repeated another four times. Steps 4 to 6 were repeated four times with the distances 25 metres, 50 metres, 75 metres and 100 metres. For 75 metres, the participants ran one lap of 50 metres and then one lap of 25 metres, and for 100 metres, the participants ran two laps of 50 metres. A total of 30 pulse measurements were taken during the duration of the experiment. Sufficiency: To minimize sources of errors, an ideal total number of 5 trials will be conducted for this experiment. A mean average and standard deviation can then be calculated from the results obtained which will ultimately reduce random errors and indicate the general spread or distribution of the data collected. Risk Assessment: Neither harmful procedures nor chemicals were employed during the course of this experiment. Thus, there are little risks associated with this particular practical. (1) There is a possible risk that the participants involved may injure themselves physically by either tripping or falling over on the running surface. Additionally, if participants have been injured prior this experiment, the injury may worsen. In order to avoid this, a selection of physically healthy individuals should be chosen and experimenters should inform the participants of the possible safety issues before proceeding further. In any case of injury, seek medical assistance. (2) Asthmatic participants – Vigorous exercise in this experiment could cause asthma attacks on participants diagnosed with asthma. To avoid serious injuries, select participants who are in healthy physical conditions. In case of an asthmatic participant, ensure to give them 4 puffs of their puff reliever whilst sitting upright if they begin to feel difficulty in breathing. In case of an emergency, observe whether the individual’s condition improve after provided with 4 puffs from puff reliever. If the condition remain the same or worsens, seek immediate medical assistance and contact 000 for emergency. Environmental Impact: There is no significant environmental in this particular experiment. Two people are simply performing this practical by running various distances and measuring their pulse rate to obtain raw data. Ethical Implications: Permission from participants must be confirmed before performing this experiment. It would not be extremely unethical if the experiment proceeds without the participant’s consent, however, this is an ethical implication that must be taken into consideration. Analysis: Results – Raw Data Table 1. Raw data table of results showing the resting pulse in beats per 30 seconds of two participants at 0 meter. Trial Pulse (beats per 30 secs) Uncertainty (beats per 30 secs) Participant 1 Participant 2 Participant 1 and 2 1 54 45 ± 0.5 2 52 49 ± 0.5 3 47 36 ± 0.5 4 48 44 ± 0.5 5 45 42 ± 0.5 Table 2. Raw data table of results showing the pulse in beats per 30 seconds of two participants when running 10 meters. Trial Time (secs) Pulse (beats per 30 secs) Uncertainty (beats per 30 secs) Participant 1 Participant 2 Participant 1 and 2 1 02.97 64 59 ± 0.5 2 03.31 60 56 ± 0.5 3 03.69 63 54 ± 0.5 4 03.44 59 57 ± 0.5 5 03.72 57 56 ± 0.5 Table 3. Raw data table showing the pulse in beats per 30 seconds of two participants running at a distance of 25 meters. Trial Time (secs) Pulse (beats per 30 secs) Uncertainty (beats per 30 secs) Participant 1 Participant 2 Participant 1 and 2 1 06.28 68 79 ± 0.5 2 06.56 72 80 ± 0.5 3 06.87 73 81 ± 0.5 4 06.66 71 78 ± 0.5 5 06.25 72 76 ± 0.5 Table 4. Raw data table showing the pulse in beats per 30 seconds of two participants running 50 meters. Trial Time (secs) Pulse (beats per 30 secs) Uncertainty (beats per 30 secs) Participant 1 Participant 2 Participant 1 and 2 1 10.88 57 53 ± 0.5 2 11.56 57 54 ± 0.5 3 11.68 59 58 ± 0.5 4 11.55 60 56 ± 0.5 5 11.32 59 58 ± 0.5 Table 5. Raw data table showing the pulse in beats per 30 seconds of two participants running 75 meters. Trial Time (secs) Pulse (beats per 30 secs) Uncertainty (beats per 30 secs) Participant 1 Participant 2 Participant 1 and 2 1 19.75 64 72 ± 0.5 2 19.75 71 73 ± 0.5 3 21.34 71 78 ± 0.5 4 20.90 76 77 ± 0.5 5 20.47 79 78 ± 0.5 Table 6. Raw data table showing the pulse per 30 seconds of two participants running 100 meters. Trial Time (secs) Pulse (beats per 30 secs) Uncertainty (beats per 30 secs) Participant 1 Participant 2 Participant 1 and 2 1 25.15 69 81 ± 0.5 2 24.07 83 80 ± 0.5 3 25.28 79 80 ± 0.5 4 25.22 80 80 ± 0.5 5 25.03 80 80 ± 0.5 Processed Data The pulses per minute for each distance were calculated by multiplying the pulses per 30 seconds by 2. For example, the pulse in beats per minute of participant 2 during the initial trial when running 0 meter is processed as following: 45 beats per 30 seconds x 2 = 90 beats per minute. Table 7. Processed data table showing the pulse per minute at rest of two participants (0 meters). Trial Pulse (beats per min) Uncertainty (beats per min) Participant 1 Participant 2 Participant 1 and 2 1 108 90 ± 0.5 2 104 98 ± 0.5 3 94 72 ± 0.5 4 96 88 ± 0.5 5 90 84 ± 0.5 Table 8. Processed data table showing the pulse per minute of two participants running 10 meters. Trial Pulse (beats per min) Uncertainty (beats per min) Participant 1 Participant 2 Participant 1 and 2 1 128 118 ± 0.5 2 120 112 ± 0.5 3 126 108 ± 0.5 4 118 114 ± 0.5 5 114 112 ± 0.5 Table 9. Processed data table showing the pulse per minute of two participants running a distance of 25 meters. Trial Pulse (beats per min) Uncertainty (beats per min) Participant 1 Participant 2 Participant 1 and 2 1 136 158 ± 0.5 2 144 160 ± 0.5 3 146 162 ± 0.5 4 142 156 ± 0.5 5 144 152 ± 0.5 Table 10. Processed data table showing the pulse per minute of two participants running 50 meters. Trial Pulse (beats per min) Uncertainty (beats per min) Participant 1 Participant 2 Participant 1 and 2 1 128 144 ± 0.5 2 142 146 ± 0.5 3 142 156 ± 0.5 4 152 154 ± 0.5 5 158 156 ± 0.5 Table 11. Processed data table showing the pulse per minute of two participants running 75 meters. Trial Pulse (beats per min) Uncertainty (beats per min) Participant 1 Participant 2 Participant 1 and 2 1 128 144 ± 0.5 2 142 146 ± 0.5 3 142 156 ± 0.5 4 152 154 ± 0.5 5 158 156 ± 0.5 Table 12. Processed data table showing the pulse per minute of two participants running 100 meters. Trial Pulse (beats per min) Uncertainty (beats per 30 secs) Participant 1 Participant 2 Participant 1 and 2 1 138 162 ± 0.5 2 166 160 ± 0.5 3 158 160 ± 0.5 4 160 160 ± 0.5 5 160 160 ± 0.5 Distance (m) Average Pulse (beats per min) Uncertainty (beats per min) Standard Deviation (beats per min) Participant 1 Participant 2 Participant 1 Participant 2 Participant 1 Participant 2 0 98 86 ± 2.5 ± 2.5 7 9 10 121 113 ± 2.5 ± 2.5 5 3 25 117 112 ± 2.5 ± 2.5 2 4 50 142 158 ± 2.5 ± 2.5 3 3 75 144 151 ± 2.5 ± 2.5 10 5 100 156 160 ± 2.5 ± 2.5 10 1 Table 13. Processed data table showing the average pulse per minute of both participants in all running distances. In order to calculate the average pulse per minute, all the different calculated pulse per minute were added together and then divided by the number of trials, and there were 5 trials. To demonstrate, the average resting pulse per minute (0 meters) for the second participant was determined using the following method: The standard deviation of the data collected were calculated using the Microsoft Excel using the function “=STDEV.P”. Graph 1. The average pulse (per minute) of two participants when exercising at different distances (0m, 10m, 25m, 50m, 75m, 100m). Error bars represent the standard deviation (spread of data). Conclusion: From the results obtained, it is apparent that there is an obvious correlation between the distance ran and the heart rate. The trend of the linear graph above shows that as the distance ran by participants increased, so did the heart rate. The measured average resting heart rate of participant one was 98 bpm. When the participant ran 10m, 25m, 50m, 75m, 100m, their average heart rate increased to 121 bpm, 117 bpm, 142 bpm, 144 bpm and 156 bpm, respectively. As predicted, the individual’s heart increased with increasing distance, however, there was a decline from 121 bpm (after running 10 meters) to 117 bpm (after running 25 meters). Similarly, the average resting heart rate of participant two was 86 bpm, and increased to 113 bpm, 112 bpm, 158 bpm, 151 bpm, 160 bpm after running 0m, 10m, 25m, 50m, 75m, 100m, respectively. The individual’s heart rate increased as the distance ran increased. However, there is a decline from 113 bpm (after running 10 meters) to 112 bpm (after running 25 meters) followed by a steep decline from 158 bpm (after running 50 meters) to 151 bpm, after running 75 meters. Consequently, the heart rate began to rise again after running 100 meters. The results above indicated and followed the expected outcome to an extent, which hypothesized that heart rate will increase as exercise intensity increases, indicated by various running distances. However, the pulse rate measured after running 10 and 50 meters of both participants were higher than expected and did not fit into the trend. As both participants experienced an unusual fluctuation in pulse rate after running 10 and 50 meters, it is possible that errors and mistakes could have occurred as the experiment was conducted. Both participants displayed this correlation regardless of being physically healthy individuals. This could have perhaps affected the experimental results obtained. Evaluation: Errors and mistakes Systematic errors: Systematic errors occurs due to inherent errors in the experimental set up which causes the results obtained to be skewed in the same direction. (1) Uncertainty of stopwatch – The stopwatch used was not necessarily accurate in its calibration. There is a possibility for error in the production of the stopwatch that caused it to be not as accurate as desired. This is a systematic error, which could have introduced errors into the experiments, generating outliers that did not particular fit into the identified correlation and trend. (2) Measuring tape – Similar to the stopwatch, the calibration in the measuring tape may not be as accurate as assumed. Consequently, this introduced systematic errors into the experiment, as the distance measured is not as accurate and precise. This may result in the participants running in either slightly greater or smaller distances. Thus, it follows that the raw pulse rate data measured will be affected, levying the error onto the processed data, which ultimately result in a higher degree of errors in this experiment than expected. Random errors: All experiments have random error, which occurs as no measurement can be made to the exact infinite precision. (3) Incorrect pulse reading – Pulse in the wrist and below the neck can be felt only briefly as the blood flows in a very fast pace. As a result, there is a possibility that the participants incorrectly counted the number of heartbeats per minute to determine the pulse rate. Additionally, participants could have counted pulses that began before the 30 seconds mark or pulses that started after the 30 seconds mark ended. These are known as “half pulses”. Ultimately, this could have introduced random errors into the results obtained, affecting the processing of raw data as well as the trend derived and the analysis given. (4) Irregular resting periods – Irregular resting periods results in different initial pulse rate at the beginning of each trial. This could have potentially affected the next set of pulse rate that is calculated and processed. When the heart is pumping blood rapidly throughout the body the pulse rate will be quite fast. If not given enough resting period before the next trial, the heart rate would still be reasonably high, which would affect the measurement of the pulse rate in the next trial. This random error has introduced error into the experiment as irregular resting periods, giving results that are not particular accurate or precise. The average and standard deviation of results were calculated which, to an extent, helped minimize the random errors made in the practical Improvements Following the identification of various systematic and random errors in this scientific experiment, improvements would need to be made to ensure the future efficiencies of this practical. Initially, to prevent systematic errors, the possible improvement that could be made is to use a highly accurate stopwatches and measuring tapes that has a close to accurate calibration, which could potentially prevent any systematic errors from occurring. In order to improve the random errors, various aspects may need to be modified and improved. As mentioned above, errors occur when an individual measure their own pulse rate. This could perhaps be due to the fact that different individuals take different approaches in measuring their pulse rate. Additionally, participants could have counted the pulse either before the 30 seconds mark has started or after the 30 seconds has ended. These are called “half pulses”. To minimize this error, there should be the same person measuring the pulses for different participants. Regarding the half pulse, an improvement for the error that this introduced could be to set up a specific criterion for when the pulse is being counted. For example, all half pulses that starts – either before the 30 seconds began or after the 30 seconds has ended – should be disregarded. Using different methods of measuring pulse will also improve the experiment. In place of the manual method, a monitor method could be employed to minimize random errors present in the experiment. A heart rate monitor can e used to get a more accurate measurement of the heart rate. There is also a heart rate phone App on both android and apple phones that can measure heart rate quite accurately. This is particularly effective during exercise where the motion of participants often make it difficult to derive a clear measurement using the manual method. Irregular resting periods can result in measurement of pulse rate. Longer resting periods should be granted to the participants involved ensuring that the value of the resting heart rate before each trial is the same. For slow pace exercise, resting periods can last for 2 to 3 minutes. For vigorous exercise, resting periods should be around 5 to 7 minutes. This will minimize the random errors and eliminate any outliers that do not fit into the trend. Furthermore, a wider variety of distances should be included in the experiment, and the practical should be completed on the same day. This is because the number of results obtained will increase so a more accurate mean and standard deviation can be determined. The practical should be completed on the same day because the participants’ health conditions and emotions may encounter a change over the two days, which can interfere with the accuracy and precision of the results obtained. Conclusion The experiment obtained results and the trend established were within our expectations despite having some outliers that did not fit into the hypothesis. This is due to the systematic and random errors that occurred during the experiment. Thus, different methods for improvements have been evaluated above to eliminate errors in the future. Bibliography Asthma Emergency. (n.d.). Retrieved from Asthma Australia: http://www.asthmaaustralia.org.au/Asthma_emergency.aspx Asthma First Aid. (n.d.). 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Retrieved from For Dummies: http://www.dummies.com/how-to/content/what-is-the-cardiovascular-system.html Human Physiology Practical – Phuong NguyenPartners: Christabel Lau, Jennifer Lin, Mengfei Yin November 13, 2015 Human Physiology Practical – Phuong Nguyen Partners: Christabel Lau, Jennifer Lin, Mengfei Yin November 13, 2015