Posted by Can the Heart Grow With Daily Exercise:
Hello Everyone! This is my short summary of how exercise and physical activity impacts the cardiovascular system:
The Heart is an interesting and unique muscle in the body, unlike all of the others and singular in its purpose, unlike other muscle groups such as skeletal muscles. Many have heard the old “working out is good for your heart,” but is this really true, and if it is, what effect does physical exercise actually have on your heart? Here are some commonly posed questions involving the heart and exercise, and what relationship they have with each other!:
How Does Exercise Impact the Cardiovascular System (The Heart)?:
Many have heard the old “working out is good for your heart,” but is this really true, and if it is, what effect does physical exercise actually have on your heart? Physical exercise not only contributes to the maintenance and growth of skeletal muscles throughout the body, but it is also good for the health of the cardiovascular system. Moderate exercise, or physical activity which raises the heart’s BPM, such as walking, jogging, and swimming, (compared to leisurely exercises such as golfing), has multiple benefits, including its contribution to the heart’s overall health.According to the Center for Disease Control and Prevention, “the cardiovascular response to exercise is directly proportional to the skeletal muscle oxygen demands for any given amount of work, and oxygen uptake ( VO2) increases linearly with increasing rates of work.” (Åstrand et al.) The study continued, stating that cardiac output, which is the product of heart rate and stroke volume, (“SV= volume of blood pumped per beat”), determining the amount of blood pumped by the left ventricle per minute, plays a critical role in “meeting the oxygen demands for work.” (Åstrand et al.) Cardiac output then, with exercise, must “increase in a nearly linear manner in order to meet the increasing oxygen demand, but only up to a point where it meets its maximum capacity.” (Åstrand et al.) Cardiac output does not change much with exercise when at rest, but according to the Center, “At or near maximal rates of work, cardiac output is increased substantially, up to thirty percent or more.” (Åstrand et al.) The study continues with “There are more important differences in the responses of stroke volume and heart rate to training. After training, stroke volume is increased at rest, during submaximal exercise and during maximal exercise; conversely, post-training heart rate is decreased at rest and during submaximal training, and is usually unchanged at maximal rates of work.” (Åstrand et al.) Moderate exercise therefore has a positive effect on overall cardiac output, as well as on stroke volume and heart rate. According to the National Library of Medicine, “ Physically active individuals have lower blood pressure, higher insulin sensitivity and a more favorable plasma lipoprotein profile. Animal models of exercise show that repeated physical activity suppresses atherogenesis and increases the availability of vasodilatory mediators such as nitric oxide.” (Matthew A. Nystoriak and Aruni Bhatnagar) The article, titled “Cardiovascular Effects and Benefits of Exercise,” continues on to state, “exercise increases cardiac output and blood pressure, but individuals adapted to exercise show lower resting heart rates and cardiac hypertrophy.” (Matthew A. Nystoriak and Aruni Bhatnagar) Exercise does this by building up the heart’s stamina and strength, as during physical activity it works harder to supply the body with more oxygen, and thus it has to beat faster than if the individual was at a standstill. The heart beats faster and with stronger contractions in order to maintain the blood flow throughout the body, as more oxygen is being used by the skeletal muscles.
Is There Such A Thing As Too Much Exercise?: There has been some debate as to how much exercise is good for the body, and when it becomes too extreme and can actually be damaging for the body. According to the National Library of Medicine, “Even though moderate levels of exercise have been found to be consistently associated with a reduction in cardiovascular disease risk, there is evidence to suggest that continuously high levels of exercise (e.g. marathon running) could have detrimental effects on cardiovascular health.” (Matthew A. Nystoriak and Aruni Bhatnagar) However, the connection between the dosage of exercise and the heart’s response to it has not been made clear, and according to the Library of Medicine, “further studies are needed to identify the mechanisms that improve cardiovascular benefits of exercise in order to develop more effective exercise regimens, test the interaction between diet and exercise, and develop pharmacological interventions for those unwilling or unable to exercise.” (Matthew A. Nystoriak and Aruni Bhatnagar) According to the Cleveland Clinic, on heart risks associated with extreme exercise, “chronic extreme exercise training and competing in endurance events can lead to heart damage and rhythm disorders.” (Clinic) According to a study conducted by the National Library of Medicine, involving thirteen women and twelve men randomly selected from four hundred and twenty-five faithful marathon participants, labs conducted after the race concluded that “A total of 10/25, (40%) met the acute injury network definition of acute kidney injury, AKI, based on a rise in serum creatine.” (McCullough et al.) The Cleveland Clinic continued, stating that “These damage indicators usually go away by themselves, but when the heart endures extreme physical stress over and over, the temporary damage may lead to remodeling of the heart or physical changes such as thicker walls and scarring of the heart.” (Clinic) Thickened walls of the heart, the septum, can lead to a series of complications including “atrial fibrillation (Afib),” defined by the mayo clinic as “an irregular and often very rapid heartbeat. Afib also raises the chance of blood clots, which can travel to the brain and cause a stroke.” (“Hypertrophic Cardiomyopathy – Symptoms and Causes – Mayo Clinic”) Another complication which may arise with thickening of the septum of the heart is “blocked blood flow,” which is a result from the narrowing of the heart and can cause “shortness of breath in activity, chest pain, dizziness, and fainting spells.” (“Hypertrophic Cardiomyopathy – Symptoms and Causes – Mayo Clinic”)
Works Cited:
Åstrand, PO, et al. “Physiologic Responses and Long-Term Adaptations to Exercise.” Selected Textbooks on Exercise Physiology, www.cdc.gov/nccdphp/sgr/pdf/chap3.pdf.
“Hypertrophic Cardiomyopathy – Symptoms and Causes – Mayo Clinic.” Mayo Clinic, 23 Feb. 2024, www.mayoclinic.org/diseases-conditions/hypertrophic-cardiomyopathy/symptoms-causes/syc-20350198#:~:text=A%20thickened%20heart%20muscle%20and,brain%20and%20cause%20a%20stroke.
McCullough, Peter A., et al. “Changes in Renal Markers and Acute Kidney Injury After Marathon Running.” Nephrology, vol. 16, no. 2, Jan. 2011, pp. 194–99. https://doi.org/10.1111/j.1440-1797.2010.01354.x.
Clinic, Cleveland. “Heart Risks Associated With Extreme Exercise.” Cleveland Clinic, 19 Mar. 2024, health.clevelandclinic.org/can-too-much-extreme-exercise-damage-your-heart.