Blood Pressure Responses to Exercise’

Introduction:
Blood pressure is a measure of the force exerted by blood flow against the walls of the arteries as it transverses the body (Bakke et al., 2006). Systolic blood pressure refers to the pressure in the arteries during the contraction of the heart and diastolic blood pressure is where the pressure is exrted on the blood vessels during heart relaxation (Michelsen and Otterstad, 1990)Various researchers have conducted studies on the differences in blood pressure responses to isometric exercise compared to dynamic exercise. For instance, Kingwell and Jennings (1993) undertook the study to determine the blood pressure at rest and during maximum dynamic exercise and compared the results to blood pressure at isometric exercise and have established that there is a direct relation between blood pressure, isometric and dynamic exercises and the body surface area of an individual. However, a common conclusion in most of these studies established that the percentage change in blood pressure to each stress was inversely relational to the resting blood pressure. The differences in blood pressure response in this context indicate that the proportional change in the blood pressure in relation to each stress declines as the resting blood pressure increased. This study shall aim at discussing the blood pressure responses to exercise and the mechanisms of the cardiovascular and respiratory systems to the blood pressure variations.
Methods:

Number of participants:
To estimate the difference in blood pressure due to exercise, the experimentation involved 18 individuals within the age group of 19-40 years. 14 of them were male and 4, female. The experiment was performed in the conditions of rest and exercise (dynamic and isometric) and the observations were tabulated for further analysis.
Instruments used for the experiment:
Automated sphygmomanometer (Omron M7)
Handgrip dynamometer (MIE)
Cycle ergometer (Monark 874e)
Measurement during rest:
The participant was seated comfortably and the left arm is placed at the heart level.
Measurement during Dynamic Exercise:
The participants were seated on cycle ergometer and their systolic and diastolic blood pressures are noted at rest using a manual sphygmomanometer. The participant was then instructed to cycle on the ergometer for 3 minutes and the systolic and diastolic measurements are taken again using manual sphygmomanometer. The participant was then instructed to cycle for further three minutes and the readings are taken again. After the completion of test cycle, the procedure was repeated again to verify the readings using auto- sphygmomanometer.
Measurement during Isometric Exercise:
Using a hand grip Dynamometer, the Maximum voluntary contraction (MVC) was performed and measured on the participants after the resting measurement is noted. The participants were made to perform 50 percent MVC until they were able to and the duration was measured. The blood pressure was measured immediately after that using manual sphygmomanometer and the observations were noted. The tests were repeated in duplicate to verify using an automatic sphygmomanometer and the readings were tabulated.
Results:
The results observed indicate that there is considerable increase in the systolic blood pressure after dynamic exercise whereas diastolic blood pressure recorded a notable increase. The mean arterial pressure also had a considerable rise following dynamic exercise. On the contrary, isometric exercise yielded different observations. The systolic blood pressure showed a little increase following isometric exercise and the diastolic blood pressure was observed to decrease. The mean arterial blood pressure had no deviation after the test and remained same. From the study, the results on the blood pressure responses varied depending on the different dynamics of the body. The surface area of the body was an instrumental determinant in the blood pressure levels both at rest and during exercise. The blood pressure levels were found to vary in relation to the body surface area in terms of weight and size. From the results, participants with a higher weight exhibited lower systolic and diastolic levels at rest. At rest, the participant with the highest weight of 122kg and 1.85m tall had 69 and 57 BP level at systolic and diastolic levels respectively. This could be compared to the participant with 48kg and 1.45m tall who had 97 and 71 systolic and diastolic BP levels at rest respectively. However, the results were different during exercise. The heavier participants exhibited higher levels of systolic and diastolic BP levels compared to the lighter participants. The heaviest participant had 156 and 86 systolic and diastolic BP levels respectively while the lightest participant had 109 and 81 systolic and diastolic BP levels respectively at exercise.
Observations:
Table 1: Blood Pressure Responses to Dynamic Exercise
CategoryDuring RestAfter ExerciseUnits
Mean Systolic126.6111111145.4444444(mmHg)
Mean Diastolic81.5555555682.44444444(mmHg)
Standard Deviation Systolic22.0377720919.12873484(mmHg)
Standard Deviation Diastolic12.866839388.542091094(mmHg)
MAP Mean96.5740741103.4444(mmHg)
MAP Standard Deviation15.022773810.42746(mmHg)
Table2: Blood Pressure Responses to Isometric Exercise
CategoryDuring RestAfter ExerciseUnits
Mean Systolic124.5129.2777778(mmHg)
Mean Diastolic82.9444444480.11111111(mmHg)
Standard Deviation Systolic12.3347905912.54078314(mmHg)
Standard Deviation Diastolic21.5200924511.96017356(mmHg)
MAP Mean96.796296396.5(mmHg)
MAP Standard Deviation16.44882699.128888(mmHg)
Table3: Blood Statistical analysis to determine difference between means using t-test
DESCRIPTIONP-Value (T-test score)
Systolic BP (mm Hg)
During rest and exercise After dynamic test0.003281
Diastolic BP (mmHg)
During rest and exercise
After dynamic test0.372261
MAP (mmHg) during rest and
Exercise after dynamic test0.033335
Systolic BP (mm Hg)
During rest and exercise
After isometric test0.08211226
Diastolic BP (mmHg)
During rest and exercise
After dynamic test0.283682569
MAP (mmHg) during rest and
Exercise after dynamic test
0.471696424
Discussion:
From the results, it is clear that isometric exercise produces a characteristic increase in blood pressure. This has a relation to the surface area of the body as well as the height of the individual. There is a greater increase in arterial blood pressure during static exercise compared to rest. Studies have also established that the results vary with age (Bakke et al., 2006). The results indicated that age produces a contraction of the vascular walls, which become less elastic. This is evident in the results as younger participants exhibited higher systolic and diastolic blood pressure at rest. However, the results were different during the diastolic phase at exercise because of the elasticity differences in the vascular walls. Other studies (Boutcher and Stocker, 1999; Carre, 2002) have found similar variations in blood pressure during rest and exercise. Age and body surface area have been found to contribute greatly to the results because of the variations in the size of vascular walls (Kingwell and Jennings, 1993).
Conclusions:
There is a marked increase in blood pressure during isometric activity compared to dynamic activity. Studies have recognized that there is a relation flanked by blood pressure, isometric and dynamic exercises and the body surface area of an individual (Michelsen and Otterstad, 1990; Bakke et al., 2006)
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