Introduction:
Blood Pressure is read systolic (SBP) / diastolic (DBP) in millimeters of mercury (mmHg). SBP is the amount of pressure that blood ejects on vessels from the heart. This happens right after the heart has contracted and the pressure at this point is the highest. DBP is the pressure that takes place in the blood vessels when the heart is relaxing. Essentially blood leaves the heart and floods back in every time the heart contracts and relaxes. Each contraction happens within a short period of time and a delay occurs between SBP and DBP. The delay is often only a fraction of a second because ventricles not only have to contract, but they need to fill up. Not all of the blood completely leaves the heart, the heart not only pumps blood, but the cells of the heart need blood. Normal blood pressure for males is 120/80 mmHg and normal blood pressure for females is 110/70. The top number refers to SBP and the bottom number refers to the DBP.
Knowing ones blood pressure at rest is beneficial marker for one’s health. High blood pressure is associated with an increased risk of heart disease and stroke. When blood pressure is increased at rest the heart has to work much harder to maintain the increased pressure. With all of the extra work and an increase in size from extra work the heart will slowly begin to fail. High blood pressure damages the walls of your arteries when arteries get blocked or damaged Oxygen supplies have more difficulty getting to cells or muscles. This may lead to difficulty exercising, cardiovascular diseases, heart attacks, as well as other diseases. Knowing blood pressure during exercise shows the effects of different exercise modalities on cardiovascular response.
MAP (mean arterial pressure) and RPP (rate-pressure product) are based on calculation of SBP and DBP. MAP is the average blood pressure in the body during each reading of blood pressure. MAP is determined by the cardiac output (CO), systemic vascular resistance (SVR), and central venous pressure (CVP) which is based upon the relationship between flow, pressure and resistance. RPP is the amount of oxygen consumed by the heart during each reading of blood pressure and measures myocardial oxygen expenditure and blood flow through all arteries that bring blood to the body (this excludes the pulmonary artery which brings blood to the lungs).
Four experiments conducted include the cycle ergometer, the upper body ergometer, isometric exercise, and isotonic exercise. Change in blood pressure for each type of exercise; show how blood pressure varies between different types of exercise.
It is predicted that aerobic exercise on the cycle ergometer and the upper body ergometer SBP will increase gradually hit a peak and decrease and DBP & MAP should gradually decrease. SBP in lower body are going to be greater than upper body graded exercise, DBP and MAP will be lower in lower body exercise. Constant workload exercise is going to have a lower SBP compared to upper and lower body exercise, but higher than static exercise. Constant workload MAP and DBP will be lower pressures than static exercise. Rate pressure product (RPP) will be lowest in the isometric exercise. Constant load exercise will be somewhat higher. The upper body aerobic exercise will be the next highest rate pressure product. The lower body aerobic exercise should have the highest RPP.
In these experiments, the independent variables are the types of exercise because each exercise does not change. Dependent variables include SBP, DBP, heart rate (HR), MAP, and RPP because they differ based on exercises performed.
Methods:
In this experiment four tested exercise modalities occurred and blood pressure is examined and compared to each specific exercise. Exercise workload and intensity of each exercise is what changes blood pressure.
Four different modalities of exercise to see which ones had a greater effect on the cardiovascular response. The first type of exercise tested is a sub maximal exercise on the lower extremities. Resting blood pressure is taken through a sphygmomanometer and a heart rate monitor is used to regulate the subjects HR. The subject should warm up for 2 minutes and then the test will begin starting at 50 watts. The subject should sustain 70 – 80 rpm’s until conclusion of the test. Every three minutes watts increase by 50 watts. Once 11 minutes is reached the recovery period wattage should decrease to 25. Once 14 minutes is reached the subject will cool down with 0 watts. HR is recorded at the last 30 seconds of each stage. Blood Pressure is recorded at the last minute of each stage.
The second type of exercise tested is a sub maximal upper extremity ergometer. Blood Pressure is recorded at the end of each stage. This experiment has three, three minute stages starting at 200 kgm/ min and increases by 200 kgm/ min each stage. There is also a 2 minute warm up as well as a 3 minute recovery stage, and cool down. The warm up, recovery and cool down phase have no resistance.
The third type of exercise tested is a constant load resistance exercise. The exercise chosen is the seated one armed bicep curl, 4 sets of 15 repetitions take place. Resting blood pressure and heart rate are recorded first. Each set is performed with 2 seconds of concentric movement and 2 seconds of eccentric movement. Blood Pressure and HR is recorded at the end of each set and one minute after last set.
The fourth type of exercise is an isometric static exercise. A hand held dynamometer is used, the subject should squeeze the dynamometer as hard as they can for 2-3 seconds with their dominant hand and their limb held out straight in front of them. This determines their maximum voluntary contraction (MVC), 40-50% of the subjects MVC is calculated. Blood pressure and heart rate are recorded before and after the two isometric sets and after each isometric trial. The subject is given a three minute rest period between each trial.
Once all exercises are completed MAP and RPP are calculated. An example for MAP and RPP are as follows:
MAP = (( SBP- DBP) / 3)) + DBP
MAP = (( 110- 80) / 3)) + 80 = 90
RPP = SBP * HR / 100
RPP = 110 * 88 / 100 = 96.8
Results:
At the beginning of exercise SBP is 115 mmHg, DBP is 75 mmHg, an MAP calculation is 83.33 mmHg. SBP showed a rather linear increase to its peak of 155 mmHg which occurred during 150 watts. Once the peak is attained there is a rapid decrease to its original first reading. DBP original reading is 75 mmHg, during the first 3 stages DBP rose to 80 mmHg and stayed there until recovery phase. MAP increased rather linearly with its highest point occurring at 25 watts during the recovery phase.
At the start of upper body exercise the SBP is 122 mmHg, DBP is 80 mmHg, and MAP is calculated at 94mmHg. SBP reached peak of 130mmHg with a workload of 600 kgm/ min. Diastolic pressure and MAP are at its highest point as well, 92mmHg and 104.66 mmHg respectively. Throughout exercise MAP and DBP remained rather linear until recovery and resting stage. By the end of exercise SBP, DBP, and MAP all dropped slightly below the beginning resting stage.
During constant load exercise increases in both SBP and MAP are observed. At rest the subject had values of SBP of 118 mmHg, MAP of 89.33 mmHg, and a DBP of 75 mmHg. SBP rose in all three sets with the largest occurring in the third set. The third set also had the greatest rise in regards to MAP. DBP decreased throughout two sets, the third set increased to 75 mmHg. 10 second post exercise data is almost identical to the resting values pre exercise: SBP is 116 mmHg, DBP is 75 mmHg, and MAP is 88.66 mmHg.
The dominant hand used by the subject is the right hand. The subjects MVC is determined to be 40 pounds, therefore 40-50 % of the MVC, 16- 20 lbs is used to conduct the experiment. During isometric (static) exercise the subject’s values for SBP at rest is 110 mmHg and DBP at rest is 80 mmHg. The first set the subjects SBP remains 110 mmHg, DBP shows a slight increase to 82 mmHg. For the second set SBP and DBP raised dramatically, SBP of 124 mmHg and DBP of 92 mmHg. After 3 minutes post exercise the subjects SBP and DBP both dropped. SBP drop slightly and DBP drops more dramatically. MAP increased and fell in the same fashion as DBP.
The subject began the Experiment with a resting HR of 83 BPM and as workload increases HR increase. 117 BPM is the highest heart rate reached in the experiment, this occurred at the highest workload (150 Watts). As recovery stages begin the subjects HR declines rapidly. HR at the end of exercise is 68 BPM.
HR at rest is 105 BPM and rises linearly through each increasing workload. The largest increase in HR occurs from 200 kgm/ min to 600 kgm / min, HR raised 29 BPM. During the recovery phase HR is almost identical to the 200 kgm/ min workload. At rest heart rate reads 99 BPM which is lower than the beginning of the experiment.
The average of constant load is 2.75 BPM higher than the average of static exercise. Discussion:
Typically at rest CO is 5 L/min. During exercise when the subject’s heart rate is near or at maximum the amount of blood increases significantly. If the heart rate is 200 BPM, Stroke Volume (SV) is around 150; this meant that during a heavy intensity exercise there may possibly be 30 L/min of blood circulating the body. There a several reasons why SBP changes in response to graded aerobic exercise. When workload is increased oxygen (O2) is needed to go to skeletal muscles. Signals are sent by chemoreceptors to the brain and Central Nervous System which sends signals back to the body. This makes the persons heart rate rise often even before exercise begins, which is shown in the experiments taken place. This drives SBP numbers up as exercise intensity increases. Also, SBP increases due to cells that signal hemodilation which widens blood channels that lead to skeletal muscles.
When cardiac output increase SBP increases as well, therefore DBP decreases because it’s in relaxation phase. Arteries are vasodilatated to deliver more blood to your muscles which is why SBP is increased. When the pressure is greater behind the valve it opens. When pressure is greater in front of the valve it closes. When the pressure is greater in front of the valve it does not open in the opposite direction (it is a one way valve). Therefore DBP is lowered because of the pressure on the artery walls.
Upper body aerobic exercise has a different cardiovascular response to lower body aerobic exercise. In other studies lower body graded exercise tends to have a 37% and 57% increase during moderate and heavy exercise while cycling (Ogoh 2004). The legs receive a greater percentage of the CO with exercise intensity. The percentage of CO perfusing the limbs is 21% lower exercise intensity compared to legs. Vasoconstrictor signals efficiently oppose the vasodilatory metabolites in the arms. This suggests that during whole body exercise in the upright position blood flow is different in upper and lower extremities with more emphasize on the lower body (Calbet 2007). SBP in lower body aerobic exercise is much higher overall and at its peak point of 155 mmHg compared to upper body aerobic exercise, which peak point reached 130 mmHg. This is due to more muscles being activated in lower extremities compared to arm and shoulder muscles. More O2 is needed to be delivered and peak O2 uptake is much greater in the lower body. The greater blood supply to the larger leg muscles compared to the smaller upper body muscles often translates into higher HR values during lower body exercise (Dempsey 1985). In these experiments, HR is higher during upper body aerobic exercise, but different subjects were used which does not disprove why BP is higher in lower body aerobic exercise. DBP is lower in the lower body aerobic exercise compared to upper body aerobic exercise because the arteries became more enlarged. They become more enlarged because SBP is much higher in lower body aerobic exercise.
Constant load exercise, specifically a bicep curl, the body is displaying a full range of motion while muscles are working hard for a total of 15 reps per set. The rise in SBP is explained by an increase in HR brings more blood distribution to the muscles. DBP decreased due to the arteries dilating. This is much different compared to static exercise where the muscle is contracted for a short period of time and does not display a full range of motion. Blood builds up pressure until contraction is complete and then fills into the muscle once relaxed. SBP did increase slightly and DBP increased as well because HR is not rising linearly compared to the metabolic demands of constant load exercise. HR rose just during 2 second contractions and came back to resting state faster than constant load exercise. Other studies have shown that during static handgrip tests MAP was 4% lower in dorsalis pedis artery compared to a constant load one legged extension (Olesen 1995). In this experiment, MAP results were similar.
The response between upper and lower body aerobic exercise were correct in concerns to SBP both rose rapidly with lower body exercise greater due to a larger demand for O2 and blood. DBP & MAP was also accurate for the most part in lower body exercise. DBP & MAP was not accurate in upper body exercise; there was a slight rise in DBP which was not expected. Constant load resistance had a higher SBP than static exercise which was predicted. DBP & MAP values were also predicted correctly with the exception of set 3 in constant load trial. RPP was also predicted correctly with the highest numbers coming from lower body aerobic exercise.
RPP data showed that on average lower and upper body aerobic exercise was 14.3% higher than constant load and static exercise. Myocardial Oxygen demand is much higher for lower and upper body exercise larger muscle groups have a relatively high oxygen consumption compared to constant load and static exercise. With this increased oxygen demand, the heart must remove oxygen from the arterial blood supplying the myocardium (Namasivayam 2010). These particular constant load and static exercises are not as demanding as aerobic lower and upper body exercises.
Sub maximal Exercise Protocol (Cycling)
Time (mins) | Power (Watts) | HR (BPM) | SBP (mmHg) | DBP (mmHg) | RPP | MAP | |
Rest | 0-2 | 0 | 83 | 115 | 75 | 95.45 | 83.33 |
Stage 1 | 2-5 | 50 | 90 | 125 | 80 | 112.50 | 95.00 |
Stage 2 | 5-8 | 100 | 108 | 135 | 80 | 145.80 | 98.33 |
Stage 3 | 8-11 | 150 | 117 | 155 | 80 | 181.35 | 105.00 |
Recovery | 11-14 | 25 | 88 | 150 | 85 | 132.00 | 106.66 |
Rest | 14-17 | 0 | 68 | 115 | 73 | 78.20 | 87.00 |
Subject Characteristics
Subject | Gender | Age | Height (cm) | Weight (Kg) | Training Status |
S1 | Female | 32 | 150 | 52.03 | Trained |
Submaximal Exercise Protocol (upper body ergometer)
Time (mins) | Workload (kgm/min) | HR (BPM) | SBP (mmHg) | DBP (mmHg) | RPP | MAP | |
Rest | 0-2 | 0 | 105 | 122 | 84 | 128.10 | 96.66 |
Stage 1 | 2-5 | 200 | 109 | 120 | 86 | 130.80 | 97.33 |
Stage 2 | 5-8 | 400 | 116 | 128 | 90 | 148.48 | 102.66 |
Stage 3 | 8-11 | 600 | 130 | 130 | 92 | 169.00 | 104.66 |
Recovery | 11-14 | 0 | 110 | 110 | 80 | 121.00 | 90 |
Rest | 14-17 | 0 | 99 | 120 | 79 | 118.80 | 92.66 |
Subject Characteristics
Subject | Gender | Age | Height (cm) | Weight (Kg) | Training Status |
S2 | Male | 24 | 190.5 | 88.24 | Trained |
Constant Load Resistance Exercise
Weight Lifted (kg) | HR (BPM) | SBP (mmHg) | DBP (mmHg) | RPP | MAP | |
Rest | 94 | 118 | 75 | 110.92 | 89.33 | |
Set 1 | 9.05 | 101 | 125 | 70 | 126.25 | 88.33 |
Set 2 | 9.05 | 99 | 118 | 65 | 116.82 | 82.66 |
Set 3 | 9.05 | 98 | 115 | 75 | 112.70 | 88.33 |
Set 4 | 9.05 | 95 | 112 | 70 | 106.40 | 84 |
Average | 9.05 | 98.25 | 117.5 | 70 | 115.54 | 85.83 |
1 min post exercise | 90 | 116 | 75 | 104.40 | 88.66 |
Subject Characteristics
Subject | Gender | Age | Height (cm) | Weight (Kg) | Training Status |
S3 | Male | 22 | 190.5 | 98 | Trained |
Static Exercise
MVC= 40 pound 40-50% MVC= 16 to 20 pounds
HR (BPM) | SBP (mmHg) | DBP (mmHg) | RPP | MAP | |
Rest | 88 | 110 | 80 | 96.80 | 90.00 |
Isometric trial 1 | 104 | 110 | 82 | 114.40 | 91.33 |
Isometric trial 2 | 98 | 124 | 90 | 121.52 | 101.33 |
Recovery (3 minutes post exercise) | 89 | 120 | 78 | 106.80 | 92.00 |
Subject Characteristics
Subject | Gender | Age | Height (cm) | Weight (Kg) | Training Status |
S4 | Male | 18 | 175.3 | 81.8 | Trained |
Work cited:
Calbet, JA.“Cardiac output and leg and arm blood flow during incremental exercise to exhaustion on the cycle ergometer.” Journal Of Applied Physiology. Vol. 103 (3), pp. 969-78: June 2007.
Dempsey, JA. “Adaptability of the pulmonary system to changing metabolic requirements.” American Journal of Cardiology. pp.10 59D-67D: 1985
Namasivayam, M.“Influence of aortic pressure wave components determined noninvasively on myocardial oxygen demand in men and women.” Department of Cardiology. Vol. 57, pp. 193-200: Dec. 2010.
Ogoh, S. “Middle cerebral artery flow velocity and pulse pressure during dynamic exercise in humans.” American Journal of Physiology. Heart and Circulatory Physiology. Vol. 288: Dec. 2004.
Olesen, HL. “Reduced arterial diameter during static exercise in humans.” Clinical Trial; Journal Article. Vol. 153 pp. 335-41: April 1995.
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