Showing cardiovascular and ventilatory responses at rest and during exercise Essay Example for Free

Showing cardiovascular and ventilatory responses at rest and during exercise Essay Abstract Objective: The objective of this experiment is to analyse how the cardiovascular and respiratory parameters are affected by steady state exercise. Method: The experiment was split into two stages, rest and exercise. A spirometer, an ECG, a Douglas bag and a blood pressure monitor were used at rest on the subject. In the exercise phase a Douglas bag and the blood pressure monitor were used to measure the subject’s volume of air and blood pressure respectively. Results: A positive correlation was calculated for the heart rate, total volume, oxygen consumption, CO2 production, pCO2, and % of CO2, minute volume, ventilation rate, mean arterial pressure and the number of breaths when the subject was exercising. The pO2, the %O2 and the respiratory quotient showed a negative correlation in the exercise phase. There was no significant change in the diastolic pressure in the exercise phase. The change in tidal volume, the systolic pressure and the pulse pressure during the exercise phase showed to vary against theoretical values and would require further studies to explain these readings. Conclusion: In conclusion many of the parameters that were calculated supported previous experiments; however the tidal volume, the systolic, diastolic and the pulse pressure were not conclusive enough to observe any significant trend. Introduction The human body is a complex machine with many mysteries yet to discover. When the human genome project finished we had learnt much about our DNA and how complex the structure is. We had just scratched the service of our true potential. Our DNA plays a major role in whether we have a good or poor cardiovascular system. This is also the same for our respiratory system. Environmental factors also contribute to how effective our cardiovascular and respiratory system can be. Every so often people from different ethnic backgrounds complete against each other in events such as the Olympics and World athletic championship. Studies have shown that when exercise begins there is a rise in the cardiac output that is a consequence of an increase in the stroke volume and heart rate due to the increase in blood circulation, there is a redistribution of the blood to the working muscle by vasodilation and vasoconstriction of the arterioles (coote, 1995). With this the body adapts to changes during steady state exercise to optimise the performance and to prevent any injuries than can occur. Steady state exercise is when the body is performing at a moderate level of exercise producing a balance between production of lactic acid and the removal of lactic acid through oxidation (Thompson, 2008) Exercising on a daily basis results in an individual maintaining a healthy and balance lifestyle. A study in North America showed a group of elderly individuals between the ages of 55 to 70 performed aerobic exercises for four months. The results showed that the experimental group improved their maximal oxygen consumption by 27% (Steinhaus, 1983). This study shows that even at senior age, exercises improves the resting heart rate, systolic blood pressure at rest, sleep habits, well being, hemodynamic and overall lifestyle changes. This study also included anaerobic exercises which too showed an improvement of the individual’s health. On some occasions the production of lactic acid exceeds the removal of lactic acid. This usually occurs when the VO2max is between 55% and 65% in healthy and untrained athlete, however in highly trained endurance athletes this value can reach at 80% (McArdle, Katch Katch, 2006). This is known as the onset of blood lactate accumulation (OBLA), which refers to the level of lactate in the blood reaching around 4mM. L-1. Exercise physiologist traditionally used VO2max as the main benchmark to measure endurance exercise. This however does not fully explain all aspect of the athlete’s ability to do well in a race. An experienced long distance athlete commonly trains slightly above the point of OBLA (McArdle et al. , 2006). Currently measuring exercise intensity by the OBLA has been a more effective and accurate way in indicating the individual’s level of fitness (McArdle et al. , 2006) The causes for OBLA have not been conclusively proven; as many believe it represent the point of muscle hypoxia which is when there is an inadequate supply of oxygen that is being sent to the muscles (McArdle et al. , 2006, p 320). However the muscle lactate accumulation does not necessarily coincides with hypoxia, because the lactate in the blood can be formed even when there is a sufficient supply of oxygen. Nevertheless the imbalance between the production and elimination of lactate in the blood can cause OBLA (McArdle et al. , 2006). In this experiment the aims were to use different equipment to measure a range of cardiovascular and respiratory parameters and to investigate the ways in how the body of a healthy young individual responds to the changes when undertaking aerobic exercise at a stead state level at different intensities. The cardiovascular parameters were the heart rate, mean arterial pressure, systolic and diastolic blood pressure, pulse pressure and the subject cardiac rhythm using an electrocardiogram. The respiratory parameters were the tidal volume, vital capacity, oxygen and CO2 percentage, the number of breath in each minute, ventilation rate, oxygen consumption, CO2 production, the respiratory quotient and to analyse how the aerobic response changes at different intensities. Material and method This experiment was performed by using the guideline set in the University of Hertfordshire ‘Level 1 Human Physiology Practical Booklet’ code number 1LFS003. The following changes were made and these amendments were about the level of resistance. At level two the exercise power was changed from 80W to 75W and the same went for level three from 110W to 100W. And instead of using only two levels that were indicated in the practical booklet at page 20, a third level was initiated which had a workload of 75W. When using the spirometry, instead of using a counter-balance gas holder with a writing pen attached to the counterweight, all spirometry parameters were recorded using the computer and the subject just has to inspire and expire through a tube that is connected to the computer. Results The subject’s BMI was calculated using his height and weight measured before the start of the experiment. The total practical time was three hours in which the first hour was used to measure the control variables and ECG. The remaining two hours were used to test the different physical levels and write down the data. The %O2 was measured in the Douglas bag decreased as the intensity of the exercise increased; while the %CO2 was increasing resulting in the pCO2 and the pO2 to increase and decrease respectively. Both the O2 consumption and the CO2 production increased with each level; however the rate of CO2 production was greater than the rate of O2 consumption causing the respiratory quotient to be higher than one. The number of breaths where increasing as the intensity of the exercise increased, but the value for the control was higher than each level. This caused the total volume of air in the Douglas bag to increase but the total volume of the control was higher than level one but not for level two or three. As the volume of air increased so did the ventilation rate and the minute volume. However the tidal volume did not have a linear pattern. Between the control and level one there was a sharp increase in the tidal volume, but during level two and three the tidal volume started to decrease. Figure 1 shows the CO2 production and the O2 consumption at the different exercise intensity. There was a large increase in the subject’s heart rate from the control to level one and from level one to level two, but from level two to level three the heart rate started the plateau. Figure 2 show how each exercise power affected the heart rate of the subject. The systolic pressure increased dramatically from the control to level one. But there was a decrease in the systolic blood pressure from level one to level two and eventually a rise in the systolic blood pressure from level two to level three. The diastolic pressure decreased from the control to level one and from level one to level two the diastolic blood pressure increased. At level two to level three the diastolic pressure decreased. Both the diastolic blood pressure at level one and three was lower than the control value, which caused the pulse pressure to be similar during level one and three but the pulse pressure during level two was very different. With the changes of the blood pressure that occurred during each level the mean arterial pressure increased gradually from the control to level three. Figure 3 shows how the blood pressures were affected by the change in the exercise intensity Before the exercise we tested the subject’s lung function by using a spirometer. Figure 4 shows the respiratory parameters of the spirograph. The ratio of the force vital capacity (FVC) and the force vital capacity expired in one second (FEV1. 0) was above the normal value of 85% (McArdle et al. , 2006, p 298). An electrocardiogram was also carried out to determine the subject’s heart rate and to analyse each wave of a single cardiac cycle. Figure 5 shows the ECG of the subject showing the different waves in a single cardiac cycle. The T wave represents the repolarisation of the ventricles, the P wave represents the depolarisation of the atria, the QRS complex is the depolarisation of both ventricles, as the ventricles is larger in size than the atria; the QRS complex has a larger peak and trough. The RR interval is the time taken for the R wave to appear again on the ECG (Fox, 2011). The ECG shows that the subject has a normal heart rate subjected to his age. Discussion Our major findings is that there is a decreasing trend in pO2, %O2, the respiratory quotient, and the diastolic blood pressure while there is an increasing trend in pCO2, %CO2, heart rate, systolic and mean arterial pressure, all respiratory parameters except for the O2 levels. As the exercise power increased the %O2 and the pO2 decreased which causes the working muscles to require more oxygen to keep up with the demands of the aerobic intensity. However the level of expired CO ­2 that is collected in the Douglas bag increased as the intensity increased. This is due to the increase production of CO2 in the working muscles during respiration. In all, the level of oxygen consumed and CO2 produced caused the respiratory quotient to be slightly above one. The respiratory quotient is the ratio between the total amounts of CO2 that is being produced to the amount of oxygen needed (McArdle et al. , 2006, p 240). During the exercise phase, the subject was catabolising the carbohydrates that he consumed prior to the experiment. As the values are very close to one, all the calories were derived from the carbohydrates that the subject consumed (McArdle et al. , 2006) The subject’s tidal volume increased from the control to level 1 where there was a peak at level one. The increase in the tidal volume from the control to level one was when the ‘demand for energy increases, the tidal volume increases by expanding into both the inspiratory reserve and the expiratory reserve’ (Smith Plowman, 2008). However during level two and three the tidal volume started to decrease. This cannot be explained as sources say that exercising actually increases the tidal volume (Garrett Kirkendall, 2000) and so further investigation is needed to be performed at different exercise power. The spirometer was used to measure the subject’s lung function and this instrument would have indicated if there are any obstructions present in the airways. By using the ratio between the FVC and FEV1. 0, the subject can be identified in having any lung obstruction or none at all (McArdle et al. , 2006). The spirometer produced an accurate value of the tidal volume at rest, while using the Douglas bag breathing forcefully can overinflate the bag which can produce an overestimation of the tidal volume. Also determining the number of breaths was difficult as the non returning breathing valve was moving very quickly to accurately count it. The parameters that were measured were the total lung capacity, inspiratory reserve volume, expiratory reserve volume, residual volume, vital capacity, functional residual capacity and tidal volume. The value of the subject’s tidal volume using the spirometer was 1. 5L. This value exceeds the average value of 500ml which has been given in many different studies of a young adult male (Normal breathing, 2010). This shows that the subject has a large lung capacity, indicating that the subject has maintained a good level of fitness. During exercise the heart rate increased due to the CO2 levels stimulating the chemoreceptors in the aortic arch which overall results in an individual inspiring more O ­Ã‚ ­2 and expiring CO2 quickly (McArdle et al. , 2006). With an increase in the heart rate the systolic pressure of the blood vessels also increased. Systolic pressure is the pressure in the aorta when the ventricles are contracting’ (McArdle et al. , 2006, p334), and due to the heart rate increasing at each level the systolic pressure correlates to the change in the heart rate. The diastolic pressure is the filling of blood to the arteries when the muscles are contracting. The trend, with the value at level two ignored, see that as the exercise power increases the diastolic pressure decreases. This is because the blood vessels dilate which in turn reduced the diastolic pressure (R. Noah, personal communication, June 7, 2000). The mean arterial pressure is the average blood pressure of an individual during a cardiac cycle. The value of the mean arterial pressure increased gradually when the exercise intensity increased because of the systolic pressure increasing at a greater rate than the diastolic pressure, which deceased relatively slow. The ECG and the blood pressure monitor were used to measure the subject’s heart rate and blood pressure respectively. Both ECG and the blood pressure monitor measured the heart rate as similar values when the subject was not exercising. While the blood pressure monitor only measures the heart rate, the ECG is used to detect if the patient’s heart is beating normally. The results from the ECG indicate the subject’s heart is beating at a normal rate and rhythm. However during the practical the value of the blood pressure during level 2 did not match with the other levels and the control. The systolic pressure was lower than the systolic pressure of the control. This is due to an error that was occurring with the machine when the subject’s blood pressure was being measured and the fact that the subject was perspiring which caused the machine to slip, making it difficult to acquire an appropriate reading. With the error present at level two the value for the mean arterial pressure was also an anomaly. To make sure how results were reliable a second reading for each level was planned however, there was a time constraint which prevented the use of calculating an average. During the beginning of the practical, the subject found it difficult to maintain the speed of 50 rpm which was prescribed in the practical booklet, which could have made the value inaccurate. Some other areas where this experiment can go further is the difference in the respiratory and cardiovascular parameters between different gender groups. They have been a few studies with regards to male and female such Leddy, Horvath, Rowland ; Pendergest (1997) which mentions the effects of a high or low fat diet on the cardiovascular factor between female and male runners. Another factor to consider is the use of age and how that affects the cardiovascular and respiratory parameters. Introducing subjects who have illnesses such as asthma, chronic obstructive pulmonary disease or other cardiovascular co-morbidities would show how the heart is working when it is damaged. The one problem is that the subjects would need careful monitoring by healthcare professional. As this experiment was focussing on the aerobic exercise, an anaerobic experiment can be implemented with subjects that are trained athletes and untrained athletes to see the difference in their cardiovascular and respiratory parameters. You could also include male and female subjects with the similar athletic background to perform some anaerobic experiments to see if there are any significant differences between the two. You could also introduce different ethnic groups and see if there is any significant difference in the results. Reference Coote, J. H. (1995): Cardiovascular responses to exercise: central and reflex contributions in JORDAN, D. , and MARSHALL, J. (Eds): Cardiovascular regulation (Portland, London, 1995), Garrett, W. E. , ; Kirkendall, D. T. (2000). Exercise and sport science. Philadelphia, Lippincott Williams ; Wilkins Leddy, J Horvath, P. , Rowland, J. ; Pendergast D. (1997) Effect of a high or a low fat diet on cardiovascular risk factors in male and female runners. . Medicine and Science in Sports and Exercise, 29(1), 17-25 Normal breathing (2010) Amazing DIY breathing device. [online] Available at: http://www. normalbreathing. com/nb-word/DIY-device-short-2010. pdf [Accessed: 5 Jan 2013]. McArdle, W. D. , Katch, F. I. , Katch, V. L. (2006). Essential of Exercise Physiology. (3rd ed. ). Santa Barbara: Fitness Technology, Inc. McArdle, W. D. , Katch, F. I. , ; Katch, V. L. (2001). Exercise physiology: energy, nutrition, and human performance. Philadelphia, Lippincott Williams ; Wilkins. Smith, D. L. ; Plowman, S. A. (2008) Exercise physiology for Health, Fitness and Performance. (2nd ed . ). Baltimore: Lippincott Williams ; Wilkins. Steinhaus, L. A. (1983). Cardiovascular Response to Exercise Training in the Elderly. Unpublished thesis, University of Utah, Utah Thompson, G. , James, N. W. ; James, R. (2008). OCR PE for AS. Oxon: Bookpoint Ltd. Raizwan. N. (June 7, 2000). Blood pressure. Message posted on MadSci Network, archived at http://www. madsci. org/posts/archives/jun2000/960410763. Me. r. html. Appendix All the results that were made were placed into a table with each level indicated and the control as well. The table below shows the respiratory and cardiovascular parameters of the subject during rest and exercise. Table shows the cardiovascular and respiratory parameters of the subject at each level and the baseline of the O2  ­and the CO2 in the classroom. To calculate the mean arterial pressure you: As the mean arterial pressure indicates the average blood pressure of a human, the diastolic phase is longer than the systolic phase, hence the reason to multiply the diastolic pressure by two. By using the values of the blood pressure the mean arterial pressure can be calculated: The ventilation rate is the rate at which the air move into the lungs and out of the lungs. This can easily be calculated by the following equation: This is the value at the control level: When calculated the ventialtion rate it is more effective to calculate the mintue ventilation instead as this corresponds to the amount of air that enters and leaves the lung in one minute. This is also a pretty sraight forwards equation: The minute volmume is used to indicate a quantitive value to the minute ventilation as the minute volume is about the amount of air inspired and expired in one minute. The minute volume is the product of the tidal volume and the minute ventilation as shown in this equation: The partial pressure of the two gases, oxygen and CO2 are used to measuere the amount of oxygen and CO2 that are being expired by the body. The equations for the two gases are shown below: The oxygen consumption is the amount of oxygen that the person inspires and transported to the cells by haemoglobin. This is to measure the efficiency of the subject; how much oxygen is that person actually using? The equation is: The CO2 production is the amount of CO2 that is expired from the lungs by the process of gases exchange between oxygen and CO2. Through the process of respiration, the cells produce CO2 as a waste product, and with the help of diffusion, the pCO2 in the cells is higher than in the blood stream so diffusion takes place. The equation is: The respiratory quotient is used to measure what type of fuel the individual is consuming (McArdle et al. , 2006) and the equation is shown below. The peak expiratory flow is used to determine how fast the person is able to expire and is used to test the function of the lungs and to see if there are any obstructions are present. The equation and example are: The equation for the FEV1: FVC and example that was used during the experiment: To calculate the BMI: The value of the subject’s BMI was: