Effect of Exercise on Cardiac Output (Lab 2) PDF

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Summary

Cardiac output can adapt with proper training. All elite athletes incorporate some form of cross training that normal include high intensity training. There are three main adaptations that will take place: increased ventricle size, decreased exercise heart rate and increased stroke volume. Therefore...

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Laboratory Report

LABORATORY REPORT Activity: Name: Instructor: Date:

Effect of Exercise on Cardiac Output Celestial Romero Professor Marissa Fukunaga 09.15.2021

Predictions 1. During exercise HR will increase

2. During exercise SV will increase

3. During exercise CO will increase

Materials and Methods 1. Dependent Variable EDV, ESV, and cardiac cycle length

2. Independent Variable level of physical activity (resting or exercise)

3. Controlled Variables age, weight, height, health, gender

4. What instrument was used to measure cardiac volumes? An MRI Scan was used to measure cardiac volumes. MRI (Magnetic resonance imaging).

5. Does the instrument used to measure cardiac volume use X-Rays? Explain. No, an MRI uses a powerful magnet in conjunction with radio frequency waves to generate images of your internal organs and structures.

Results Table 2: Resting and Exercising Cardiac Cycle Length, EDV, and ESV

Subject 1 Subject 2 Subject 3 Averages

Cardiac cycle length (msec) 818 827 836

Resting Values EDV (mL)

ESV (mL)

136 141 144 140

67 70 71 69

Cardiac cycle length (msec) 403 371 414

Exercising Values EDV (mL)

ESV (mL)

144 140 140 141

36 33 35 35

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Laboratory Report

Resting and Exercising HR and EDV Strokes/min Resting Values

450 360

Exercising Values

1. HR

270 180 90 0 1

mL Resting Values

150 120

Exercising Values

1. EDV

90 60 30 0 1

1. Resting and exercising cardiac cycle length a. What was the average resting cardiac cycle length? The average resting cardiac cycle length was 827 msec.

b. What was the average exercising cardiac cycle length? The average exercising cardiac cycle length was 396 msec.

c. The range of normal resting cardiac cycle length is between 818 and 858 ms. Did average cardiac cycle length increase, decrease, or not change with exercise? The cardia cycle length decreased with exercise.

2. Resting and exercising EDV a. What was the average resting EDV? The average resting EDV was 140 mL.

b. What was the average exercising EDV? The average exercising EDV was 141 mL.

c. The range of normal resting EDV is between 135 and 145 ml for these subjects. Did average EDV increase, decrease, or not change with exercise? The average EDV increased by only (1) mL with exercise.

3. Resting and exercising ESV a. What was the average resting ESV? The average resting ESV was 69 mL.

b. What was the average exercising ESV? The average exercising ESV was 35 mL.

c. The range of normal resting ESV is between 65 and 75 for these subjects. Did average ESV increase, decrease, or not change with exercise?

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Laboratory Report

The average ESV decreased with exercise.

Table 3: Resting and Exercising HR, SV and CO

Subject 1 Subject 2 Subject 3 Averages

HR (strokes per second) 73 73 72 72

Resting Values SV (mL) SV (L) 69 71 73

0.069 0.071 0.073 0.071

CO 5.0 5.2 5.3 5.2

Exercising Values SV (mL) SV (L)

HR (strokes per second) 149 162 145 152

108 107 105

0.108 0.107 0.105 0.107

CO 16.1 17.3 15.2 16.2

Resting and Exercising SV and CO mL Resting Values

100 80

Exercising Values

1. ESV

60 40 20 0 1

L Resting Values

0.2 0.16

Exercising Values

1. SV

0.12 0.08 0.04 0 1

L/min Resting Values

40 32

Exercising Values

1. CO

24 16 8 0 1

4. Resting and exercising HR a. What was the average resting HR? The average resting HR is 72 strokes per minute.

b. What was the average exercising HR? The average exercising HR is 152 strokes per minute.

c. The range of normal resting HR is between 70 and 73 beats per minute for these subjects. Did average HR increase, decrease, or not change with exercise?

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Laboratory Report

The average heart rate increased with exercise.

5. Resting and exercising SV a. What was the average resting SV? The average resting SV is 71 mL.

b. What was the average exercising SV? The average exercising SV (rounded to the nearest tenth) is 107 (106.6) mL.

c. The range of normal resting SV is between 60 and 80 ml for these subjects. Did average SV increase, decrease, or not change with exercise? The average SV increased with exercise.

6. Resting and exercising CO a. What was the average resting CO? The average resting CO was 5.2 (L/min.)

b. What was the average exercising CO? The average exercising CO was 16.2 (L/min.)

c. The range of normal resting CO is between 4.2 L per minute and 5.84 L for these subjects. Did average CO increase, decrease, or not change with exercise? The average CO increased with exercise.

Discussion 1. What caused the change in HR with exercise? When undergoing intense cardiac training such as running or swimming,our muscles need more oxygen to do the extra work, so your heart rate increases to compensate. 2. Discuss the effect of venous return and heart rate on exercise EDV. An increase in venous return means there is a greater volume of blood returning to the heart from the body. This causes a slight increase in the filled volume of the ventricle (EDV), meaning the muscle fibers will have to stretch more in order to contract the larger amount blood. But it is slightly compromised because if the heart rate increases, there will be a reduced diastolic filling time meaning that the EDV will actually decrease.

3. What caused the change in ESV volume with exercise? Exercise leads to increased contractility, as the heart the heart has to pump out a bigger load of blood. This leads to a decrease in ESV. 4. Why did SV change with exercise? Stroke Volume increased with exercise because larger volumes of blood were being ejected from the heart. 5. Discuss the importance of the change in CO with exercise? SV and HR increased and pumps more blood around to due to increased levels of exercise - increasing cardiac output (CO=SV*HR).

6. Restate your predictions that were correct and give data from your experiment that support them. Restate your predictions that were not correct and correct them, giving supporting data from your experiment that supports your corrections. My predictions were that HR, SV and CO would increase due to exercise. All of my predictions were correct. HR increased because muscles needed more blood/oxygen to do work. Leading to an increase in Stroke Volume, as larger volumes of blood were being ejected from the ventricles into the pulmonary arteries/aorta. CO depends on HR and SV; CO increased because there was more blood being ejected from the heart per minute.

Application 1. We measured the stroke volume of the left ventricle. What was the average stroke volume of the right ventricle at rest and after exercise? Stroke volumes are generally equal for both ventricles given the Frank-Starling mechanism.

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Laboratory Report

2. Assume that for one beat, the stroke volume of the left ventricle is greater than that of the right ventricle. Explain why in a normal heart this would be corrected on the next beat. The Frank-Starling mechanism is ideally suited for matching cardiac output to venous return. Any sudden, excessive output by one ventricle soon increases the venous return to the other ventricle. The consequent increase in diastolic fiber length in the second ventricle augments the output of that ventricle to correspond with the output of the oposit ventricle. Therefore, it is the Frank-Starling mechanism that maintains a precise balance between the outputs of the right and left ventricles. 3. Explain why elite athletes have a lower than normal heart rate, yet have a higher than normal ability to increase cardiac output. Cardiac output can adapt with proper training. All elite athletes incorporate some form of cross training that normal include high intensity training. There are three main adaptations that will take place: increased ventricle size, decreased exercise heart rate and increased stroke volume. Therefore, the heart can maintain a high cardiac output with less effort.

Laboratory Report/ Celestial Romero/ Effect of Exercise on Cardiac Output/ Professor Marissa Fukunaga/ 09.15.2021/ Page [5] of [5]...