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The Effect of Exercise on Cardiac Output Lab Report


Exercise increases the heart rate and stroke volume, raising the overall cardiac output. In this case, exercise increases the oxygen demand, requiring the heart to pump blood faster. When using magnetic resonance imaging, one can determine the impacts of a physical workout on the cardiac output, mainly by analyzing the cardiac cycle length, the end-diastolic volume, and the end-systolic volume.

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However, the effect of exercise on the cardiac cycle remains closely interlinked with the individual’s gender, age, health status, and weight. In this perspective, activity decreases the length of the cardiac cycle. The end-diastolic volume increases during exercise while the end stroke volume reduces.


Physical workout has a significant impact on an individual’s heart functioning. With the increasing rates of obesity and its related chronic conditions, health professionals encourage people in society to participate in regular physical exercise that can entail running, jogging, brisk walking, hiking, or bike riding. All such activities affect the cardiac cycle, involving how the heart pumps and receives blood to and from the other body organs. From this perspective, it is vital to note that the cardiac output is the stroke volume and heart rate function. Thus, physical exercise has a substantial effect on how the heart functions.

The cardiac cycle represents the alterations when blood flows in the heart, primarily focusing on the pressure changes during heart filling or diastole and heart contraction or systole. In this case, the heart filling or relaxation and contraction refers to the ventricular dilation or contraction. Such changes occur due to the conductive electrochemical alterations at the level of the heart muscle (Pollock & Makaryus, 2021). The valves within the heart regulate blood movement between the heart chambers. The deoxygenated blood moves from the body organs to the right atrium to the right ventricle to the pulmonary system for oxygenation. Ultimately, the blood comes to the heart’s left atrium and subsequently to the left ventricle that ejects it to the body via the aorta. Such blood movement depends on the pressure gradient between the different chambers, influencing valve opening and closure. According to Pollock and Makaryus (2021), the minimum pressure of the right atrium is 4mmHg, those of the right ventricle is 25mmHg, those of the left ventricle is 120 mmHg, and those of the pulmonary arteries and aorta are 25 and 120, respectively. In this case, blood movement from the left ventricle to the aorta happens when the pressure in the left ventricle is higher than in the aorta. For instance, during systole or ventricular contraction, the forces in the left ventricle are 120 mmHg, while those at the aorta are at 80 mmHg (Pollock & Makaryus, 2021). Hence, the cardiac cycle depicts the heart changes as blood flows in various chambers.

The average value of the heart rate of an adult patient is between 60 and 100 beats per minute. Shaffer and Ginsberg (2017) contend that heart rate variation is a function of the interactions between the cardiac system and the brain and the vigorous processes of the autonomic nervous system. Factors that can affect a person’s heart rate include exercise, drugs such as beta-blockers, caffeine, and anxiety. During exercise, the increased blood flow to meet the body’s oxygen demands increases the heart rate since the heart is pumping faster. Beta-blockers contribute to vasodilation while reducing the impacts of adrenaline, decreasing the rate at which the heart pumps blood. Caffeine stimulates the autonomic nervous system by enhancing the release of adrenaline, increasing the heart rate (Gonzaga, Vanderlei, Gomes, & Valenti, 2017). Anxiety directly increases the adrenaline levels, increasing the heart rate.

The stroke volume encompasses the blood pumped out of the heart for every ventricular contraction or heartbeat. In this case, the typical stroke volume of a seventy kilograms adult is roughly seventy milliliters (Bruss & Raja, 2021). Hyperthyroidism, exercise, and heart muscle disease such as cardiomyopathy. The former two increase the contractility by affecting autonomic control, while cardiomyopathies affect the heart’s contractility, reducing the stroke volume.

The average cardiac output levels are between 5 and 6 liters per minute, while one acquires the figure by multiplying the stroke volume by the heart rate (King & Lowery, 2021). In this case, exercise increases the cardiac output by increasing the adrenaline and noradrenaline levels in the blood and the sympathetic tone, elevating the heart rate. Besides, exercise increases the stroke volume, increasing the cardiac output.


Bruss, Z.S, & Raja, A. (2021, Sep 14). Physiology, stroke volume. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Retrieved from
Gonzaga, L. A., Vanderlei, L., Gomes, R. L., & Valenti, V. E. (2017). Caffeine affects autonomic control of heart rate and blood pressure recovery after aerobic exercise in young adults: A crossover study. Scientific Reports, 7(1), 14091. doi:10.1038/s41598-017-14540-4
King, J., & Lowery D. R. (2021, Jul 23). Physiology, cardiac output. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Retrieved from
Pollock, J. D., & Makaryus, A. N. (2021, Oct 9). Physiology, cardiac cycle. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Retrieved from
Shaffer, F., & Ginsberg, J. P. (2017). An overview of heart rate variability metrics and norms. Frontiers in Public Health, 5, 258. doi:10.3389/fpubh.2017.00258

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