Cardiovascular
Discussions and analysis will center around forms of cardiovascular promoting physical exercises, best practices, and current & emerging research.
We will explore the synergy, mitigation, intervention, and prevention that physical exercise plays on diseases, that are associated with poor cardiovascular health. Along with a specific focus on Aerobic and Anaerobic exercises.
Updated periodically, come back often!
Target Heart Rate
Author: Rose D.
By definition, cardiovascular exercise, or aerobic exercise, is a vigorous activity that demands cardiac exertion. Cardio activity increases heart rate, respirations, and demands more oxygen; resulting in an increase of blood flow throughout the body. The heart is responsible for pumping blood and therefore oxygen through the body.
The heart is comprised of four hollowed muscular chambers. The heart’s pumping action is controlled by an electrical conduction system, which transfers electrical activity to mechanical activity.
The rhythmic contracting and pumping motion are caused by electrical impulses responsible for maintaining the cycle of the heart. Impulses originate from the Atria to the Atrioventricular (AV) node and move through the Bundle of His and the left and right bundle branches. One at a time, electrical conduction engages heart cells, from their resting polarized state to the depolarized state. This depolarization causes a contraction. Depolarization is the mechanical activity of the heart.
When depolarization occurs, the contraction of the myocardium, causes the blood to be ejected from the ventricles. The heart is in a state of Systole, reflected in the top blood pressure reading.
While the relaxation of the myocardium, allows for the ventricles to fill, this is the state of Diastole. This state is the bottom of a blood pressure reading.
Cardiac output (CO) measures the amount of blood pumped in each ventricle in 1 minute.
It can be calculated by multiplying the stroke volume (SV) and the heart rate (HR). The stroke volume (SV) is the amount of blood ejected from the ventricles.
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Many factors can affect Cardiac Output (CO). Primary factors include hormonal changes and fluctuations; blood volume changes; and changes in heart rate which is largely controlled by the autonomic nervous system (ANS). Secondary factors include changes in extracellular fluids, age, body size, weight, genetics, sex, and emotional state, and other pre-existing conditions.
As previously discussed, Maximal Heart Rate (MHR) is a mathematical formula determined by age, with the pretense that groups of individuals of a certain age have similar heart rates.
This formula has been used for more than 90+ years when it was first produced around the 1930s. [4,6]
Emerging research is finding that the formula is highly inaccurate and suggests that individualization and population-specific variables should be considered, among other factors, not just age alone. [2, 6] While no new formula has been created to replace it, on a broader scale, there have been five that the American College of Sports Medicine has laid out in their guidelines, that are population-specific. [6] Later formulas have been sex-specific and utilized gas exchange analysis.
Factors that should be considered are rates of stress, physical and mental/emotional; the use of stimulants; and level of conditioning. Such factors as stress and the use of stimulants suggest that the autonomic nervous system (ANS) plays a greater role in exercise physiology.
Target Heart Rate is a percentage of Maximum Heart Rate (MHR), between 50% to 93% of an individual’s maximum heart rate. For moderate-intense activity, the percentage range for Target Heart Rate based on age is closer to 50% to 75%, and for vigorous activity is between 76% to 93%. [1,7]
The Target Heart Rate (THR) or the Target Heart Rate (THR range) range provides the Beats Per Minute (BPM) at which physical activity is achieved for reaching optimal physical fitness and intensity; without leading to adverse physiological effects, by exceeding or reaching Maximum Heart Rate (MHR).
As previously mentioned the constraints of the MHR formula, should be used as guidance, erring on the side of caution. Individuals should consult with their physicians before embarking on a fitness journey with cardiac activity, as several factors can affect the Target Heart Rate range. Exercise Physiologists and other Certified fitness trainers should be cognizant of these concerns when using the Target Heart Rate (THR) as a measure of effectiveness for cardiac activity.
References:
[1] Fox et al. (2007). Resting Heart Rate in Cardiovascular Disease. JACC;50 (9):823-830.
[2] Hunt, Kenneth and Saengsuwan, Jittima (2018). Changes in heart rate variability with respect to exercise intensity and
time during treadmill running. BioMed Eng; 17:128.
[3] Riebe et al. (2018). General Principles of Exercise Prescription. In: ACSM’s Guidelines for Exercise Testing and
Prescription. Wolters Kluwer/Lippincott; 10 (6): 143-179.
[4] Palatini et al. (2004). Elevated heart rate: a major risk factor for cardiovascular disease. Clin Exp Hypertens.; 26: 637- 644.
[5] Physical Activity Guidelines Advisory Committee (2008). Physical Activity Guidelines Advisory Committee Report. U.S.
Dept of Health and Human Services. Retrieved August 22, 2021 from https://health.gov/sites/default/files/2019-
09/paguide.pdf.
[6] Roberg, Robert A. and Landwehr, Roberto (2002). The Surprising History of the “HRmax=200-age” equation. An
International Electronic Journal; 5(2): 1-9.
[7] Shookster et al. (2020). Accuracy of Commonly Used Age-Predicted Maximal Heart Rate Equations. International
Journal of Exercise Science 13(7): 1242-1250.
What Is It?
Author: Rose D.
Cardiovascular exercise is an energy-generating process and is defined as exercise that raises the heart rate, breathing frequency, and increased blood circulation in the body. The increased activity of skeletal and large muscle groups during cardiovascular exercise, demands more energy, to maintain ATP production through aerobic mechanisms supplied by oxygen.
The objective of cardiovascular-promoting exercise is to increase the efficacy of muscular function and strength, by engaging the body in regular physical activities that raise the heart rate. The improvement of the body's ability to take in and use oxygen through maximal oxygen consumption or aerobic capacity; in turn, improves cardiac output that assists with overall vascular efficiency in the blood vessels.
Cardiac output is the amount of blood that the heart pumps during exercise. Heart rate increases in proportion to workload until the heart rate nears maximal rate. Target heart rate falls between resting heart rate, that is heart rate at rest, and below maximal/maximum heart rate. The target heart rate is an ideal rate to reap cardiovascular physical exercise benefits. Maximal heart rate is the greatest number of beats that the heart can beat during all-out or maximum effort. However, exceeding maximal heart rate, above 85%, can lead to dangerous adverse physiological effects; such as cardiac arrest/event (in the presence of undiagnosed/diagnosed Coronary Artery Disease); strokes; along increased probabilities of musculoskeletal and joint injury.
The primary benefits of cardiovascular health from physical activity are the adaptations of the heart (cardiac muscle) and blood vessels (vascular system) to the demands of exercise. Similar to other muscles, cardiac muscle adapts to muscle contractions and the demands of increased activity through chemical energy and physiological changes.
Collaborative research conducted individually and collectively by the Centers for Disease Control and Prevention (CDC), the American College of Sports Medicine (ACSM), and the American Heart Association (AHA) in conjunction with the 1996 U.S. Surgeon General’s Report on Physical Activity and Health convened into a panel to discuss the effects of regular physical activity on overall cardiovascular health. [2]
They found that active individuals fared better at lessening the development of Coronary Heart Disease (CHD) than sedentary individuals. Most notably, the effects of physical activity on vascular efficiency and blood vessels are the most beneficial aspects of improved cardiovascular health.
Vascular benefits are the results of improvements to the capacity of blood vessels to dilate, in response to hormones released during exercise. This continually improves vascular wall function, such as diminishing harmful plaque formation, which can impede blood flow. The overall improvement of blood flow assists with oxygen delivery to working muscles and other organs.
A sedentary lifestyle is one of the leading factors in the development of cardiac-related diseases along with these lifestyle factors, high blood pressure, abnormal values for blood lipids, smoking, and obesity. [2] Regular exercise assists with reducing and maintaining body weight, reduces bad cholesterol, raises good cholesterol, and improves insulin sensitivity. Improved insulin sensitivity can assist with controlling glucose levels which is beneficial for diabetics. Benefits are obtained from the efficient movement of blood flow through the vascular system and the heart.
Moderate physical activity, established as 30-60 minutes a day, encourages benefits towards overall cardiovascular health. Though exercise doesn't directly impact one single factor alone, daily moderate exercise, assists with improvements across the spectrum of factors. The impact of regular consistent activity extends the probability towards long-lasting and optimal cardiovascular health. When consistent cardiovascular physical activity is paired with good nutrition and cessation of risky lifestyle factors, significantly impactful results can occur on overall health.
References:
[1] Buja, Maximilian L.and Jagdish, Butany (2015). Cardiovascular Pathology: Chapter 4-Diseases of Small and Medium-sized
Blood Vessels. Academic Press, 4: 125-168.
[2] Johns Hopkins Medicine. Higher fitness linked to reduced risk of death after first heart attack (2016, February
1).ScienceDaily. Retrieved August 22, 2021 from www.sciencedaily.com/releases/2016/02/160201084350.htm
[3] Jonathan Myers, PhD (2003). Exercise and Cardiovascular Health. Circulation, 107: e2-e5.
[4] Physical Fitness Significantly Improves Survival and Prevents Heart Attacks in People with Stable Coronary Artery Disease. John Hopkins Medicine: Heart and Vascular Institute (2013 November 13). John Hopkins. Retrieved 2020, from https://www.hopkinsmedicine.org/news/media/releases/physical_fitness_significantly_improves_survival
_and_prevents_heart_attacks_in_people_with_stable_coronary_artery_disease
