Monitoring and Recording of Heart Rate - Coursework Example

Assessment of the Heart Rate and Oxygen uptake al affiliation: The main objective of the practical was toassess and monitor the heart rate (HR bpm) and oxygen uptake (VO2ml.kg-1.min-1) to an imposed work load or exercise. In this case, monitoring and recording of heart rate as well as expired air management and collection in a Douglas bag was undertaken. Timing was considered to be very critical in the overall experiment. Basing on the results, it is clearly evident that heart rate and Vo2 increased with increase in work load or exercise. Key words: heart rate, work load, Vo2 Introduction The main objective of the practical was to assess and monitor the heart rate (HR bpm) and oxygen uptake (VO2ml.kg-1.min-1) to an imposed work load or exercise. Exercise testing involves assessing the pulmonary gas exchange and cardiac response to an imposed exercise load. Changes in blood pressure, heart rate exercise perceived level as well as respiration provide data that can be used in quantitative estimation of cardiovascular function and conditioning. Exercise tests involve observing an individual during exercise. Through heart rate and blood pressure monitoring, it is possible to determine the changes in hemodynamic response and disturbances in heart rhythm and conduction related to exercise can be classified. Cardiovascular abnormalities not experienced at rest could be elicited by exercise and it can be applied in assessing the cardiovascular system function. Large muscle group contraction as a result of dynamic exercise gives a volume load to left ventricle (Cohn 1987). In this case, the response of cardiovascular is proportional to exercise level. There is a quick increase in oxygen uptake at the onset of dynamic exercise. Oxygen uptake after several minutes normally remains stable (the condition referred to as steady state) at each exercise intensity. At this stage, the cardiac output, heart rate, pulmonary ventilation and blood pressure are seen to be relatively maintained at constants levels (Rowell 1986). Maximal oxygen consumption (Vo2max) is known to be the greatest oxygen amount an individual can consume during dynamic exercise. Maximal Vo2 can be got by multiplying maximum arteriovenous oxygen (aVo2) difference and the maximum cardiac output. Because cardiac output is equivalent to stroke volume product and heart rate, maximal volume is directly associated with heart rate the arteriovenous oxygen difference during exercise is seen to have a physiological limit that is 15-17ml/dl. In this case, if there is achievement of maximum effort, maximal volume could be used to determine the maximal cardiac output (Rowell 1986). Methods The apparatus used in the experiment included Polar heart rate monitor, elephant tubing carbon dioxide analyzer, Stop watch, mouthpiece and one way valve, oxygen analyzer, Monark bicycle ergometer, nose clip Douglas bag and gasometer. In order to meet the objective of the experiment, the responsibilities were designated as follows; monitoring and recording of heart rate, expired air management as well as collection in a Douglas bag, expired air analysis in Douglas bag. During the attachment of heart rate monitor; one end of the elastic trap was attached to the chest band, the two heart rate transmitter electrodes surfaces were moistened then placed on the subject’s chest. The elastic trap was then passed around the subject’s back then attached to the heart rate transmitter. The transmitter was fitted tightly on the chest just below the pectoralis major muscle. The subject was allowed to sit on a chair and remain quiet and still during the resting phase (12 minutes).The resting heart rate was got by recording the HR every half minute during the last resting phase 6 minutes also the mean value was determined. The mouthpiece was also placed into the mouth of the subject at 5 and 30 seconds. The expired air was collected on the 6th minute after the turning of breathing valve and the valve was closed at the 12th minute After the resting phase, the subject took up position on the cycle ergometer. In this case, the hip movement was observed to find out if there was excessive hip rocking. The heart rate receiver was attached to the ergometer handle bar. The clock was started at time 0 minutes and the subject was allowed to start exercising at 50 pedal revolutions per minute at 50 watts work load. After 4 minutes, the work load was set at 100 watts and exercising was continued for further 4 minutes and the heart rate was recorded at an interval of half minute for a period of 8 minutes. The heart rate was monitored every 30 seconds for 3 minutes into recovery immediately after the exercise. Gas collection was only carried out in the steady state phase. After collecting the mixed expired gas volume, the content was agitated then later analyzed for concentrations. Gas measurement was then undertaken Results Subject Condition Heart rate (bpm)   Rest HR 1   74 2   67 3   81 4   73 5   81 6   81         50w   1   98 2   96 3   105 4   116 5   107 6   118         100w   1   107 2   123 3   138 4   136 5   140 6   133 Table1. The heart rate data for the subject Basing on the above table, it is observed that the heart rate of the subject increased with time at all the three conditions that include rest 50watts and 100watts. Figure 1.Graph of heart rate against time for all subjects. The above figure clearly shows that the heart rate at 100watts work load was the highest followed by 50 watts then rest. Figure2. Graph of VO2 for all subjects Basing on the above figure, it is clearly evident that the Vo2 was the highest at 50 work load but the least at rest. The Vo2 is almost similar at 50watts and 100 watts work load. Discussion The main objective of the practical was to assess and monitor the heart rate (HR bpm) and oxygen uptake (VO2ml.kg-1.min-1) to an imposed work load. Basing on the results, it is clearly evident that both the heart rate and oxygen uptake increased with increase in work load with time or during exercise. This is supported by the fact that there is a quick increase in oxygen uptake at the onset of dynamic exercise. Oxygen uptake after several minutes normally remains stable (the condition referred to as steady state) at each exercise intensity (Cohn 1987). It can as well be observed that the Vo2 was the highest at 50 work loads but the least at rest (fig2), but Vo2 is almost similar at 50watts and 100 watts work load. This simply means that the Vo2 increases with work load that it reaches maximum or it remains constant at a later stage. According to literature, it is known that there is a rapid increase in oxygen uptake at the onset of dynamic exercise and oxygen uptake after several minutes normally remains stable (the condition referred to as steady state) at each exercise intensity (Rowell 1986). An increase in heart rate as a result of decrease in vagal output is considered to be cardiovascular system response that is immediate to exercise and it is followed by sympathetic outflow increase to system blood vessels and heart that normally to heart rate increase (Stein et al.2000) Conclusion The objective of the experiment was met and the findings were in line with the previous studies undertaken. In this case, if there is achievement of maximum effort, maximal volume could be used to determine the maximal cardiac output. The heart rate and oxygen uptake is directly proportional to the work upload or exercise. References Cohn JN, ed. (1987). Quantitative exercise testing for the cardiac patient: the value of monitoring gas exchange: introduction. Circulation. 76(suppl VI): I-1–VI-2. Rowell LB, ed.(1986). Human Circulation: Regulation During Physical Stress. New York: Oxford University Press Stein R, Chaitman B, Balady G J, et al. (2000) Safety and utility of exercise testing in emergency room chest pain centers: an advisory from the Committee on Exercise, Rehabilitation, and Prevention, Council on Clinical Cardiology, American Heart Association. Circulation; 102: 1463–1467. Read More