Due by Day 7. Read several of your classmates’ posts and respond to two students who have chosen a different system. In your response, address a limitation or dysfunction of this system that may hinder exercise performance. Each peer response should be at least 100 words in length and include one additional scholarly resource.
Jan 28, 2021 at 10:20 AM
Hello Megan, I believe that I will be greatly resourceful and will help you gain a deeper understanding of the cardiovascular system as it relates to exercise. I will begin with a brief introduction to the cardiovascular system. I will begin with a brief introduction to the cardiovascular system (Katch, McArdle, & Katch, 2015). The cardiovascular system consists of the heart, the arteries, the capillaries, and the veins. The heart plays an important role in ensuring that blood is circulated throughout the body. The arteries are high-pressure tubes that help deliver oxygenated blood to the tissues. Blood that is pumped from the left ventricle of the heart via the aorta is then supplied to various tissues in the body through arteries. Capillaries, on the other hand, consist of a network of microscopic blood vessels that are thin enough to allow blood cells to squeeze through (Katch, McArdle, & Katch, 2015). Veins help in maintaining the continuity of blood by ensuring that deoxygenated blood flows back to the heart. Veins contain about 65 percent of the total blood volume, and therefore they do not act as passive conduits. Evidently, the circulatory system is an interconnected system that delivers oxygenated blood to tissues and ensures that deoxygenated blood is then delivered back to the heart.
When one is resting, the blood pressure differs significantly compared to when one is exercising. At rest, the highest pressure that results from pumping by the left ventricle reaches about 120 mm Hg. When the heart relaxes, the valves of the aorta shut. Continuous pressure is provided by the arteries’ natural recoil. During the diastole phase, the blood pressure reduces to about 70 to 80 mm Hg (Katch, McArdle, & Katch, 2015). However, the pressure can be affected by various factors, including the mineral and fat deposits within the walls of the arteries. The fat and mineral deposits create resistance and can result in a systole pressure of over 300 mm Hg and diastolic pressures of over 120 mm Hg. When one is exercising, the blood pressure rises. The rise in blood pressure helps supply the muscles with oxygenated blood. The result is a rise in the cardio output, which describes the number of heartbeats as well as the volume of blood that is pumped for every stroke of the heart.
The oxygen used when one is exercising and at rest also differ. When one is at rest, the myocardium extracts 70 percent or 80 percent of oxygen from the blood (Katch, McArdle, & Katch, 2015). Many tissues at rest use about 25 percent of the oxygen available in the blood. At rest, one achieves near-maximum oxygen myocardium oxygen extraction. When one is exercising, coronary blood flow increases four to six times compared to when one is resting. As the rate of exercising increases, the myocardial flow also increases to ensure that oxygen supply is matched to the demand. One important factor that is important is the VO2max. The VO2 max is the measure of the maximum oxygen consumption when one is exercising. VO2max indicates one’s level of fitness (Ross et al., 2016). A higher VO2max is indicative of higher levels of aerobic fitness. With age, the VO2max declines. As you get older, it becomes increasingly difficult to handle extended periods of exercise (Ross et al., 2016). After exercising, the cardiovascular system slows down to attain normal. Evidently, two chronic adaptations to exercise are blood pressure and cardiac output. Cardiac output increases when one is exercising. The blood pressure also increases.
Ross, R., Blair, S. N., Arena, R., Church, T. S., Després, J. P., Franklin, B. A., ... & Wisløff, U. (2016). Importance of assessing cardiorespiratory fitness in clinical practice: a case for fitness as a clinical vital sign: a scientific statement from the American Heart Association. Circulation, 134(24), e653-e699.
Meghan, I'm so happy that you realize the importance of taking care of your bodies, especially as you age. Studies have shown that being inactive leads to many diseases, premature biological aging, and a weakened immune system (Stefanović, 2016). With all of these viruses going around, why not build up our immune system with exercise? You have chosen an excellent plan for getting started. A 5k in three months is achievable, fun, and the sense of accomplishment that you will feel will have you reaching for more! I like that you are only running three days a week; this will help you recover and decrease your injury risk. At first, you will feel that you are huffing and puffing and that your respiratory system cannot keep up. Do not get discouraged. With time and training, your respiratory system will adapt, and you will find yourself surprised that you can speak and run.
Let me explain more about your respiratory system. We generally think of just the lungs, but there is more to this system. Your nose, mouth, larynx, trachea, two bronchi, bronchioles, and alveoli are all that make up your respiratory system. These components work together to supply the oxygen needed for metabolism and expel the carbon dioxide made in metabolism. They also help us retain the acid/base balance that our bodies require (Katch et al., 2015).
When you are resting, you breathe in oxygen from the atmosphere from your nose and mouth, where it is warmed, filtered, and humidified as it flows through the larynx into the trachea. From the trachea, the oxygen flows into two bronchi that divide from the trachea and are part of your right and left lung. These bronchi divide further into bronchioles, where the air continues to travel into the alveoli, which are the respiratory tract's ending sacs, where gas exchange occurs. From the lungs, oxygen is sent out to the body for metabolism, and carbon dioxide waste returns to the lung to be expelled in exhalation (Katch et al., 2015)
When you are new to running, the respiratory system must work harder to adjust to the new demand. At rest, your respiratory rate is about 12 breaths per minute. When you start running, it can go as high as 45. The amount of air moved with each breath you take is called your tidal volume. With increased exercise, your tidal volume rises. The amount of air you breathe each minute is called your minute ventilation, and it will also increase. At first, you will find yourself breathing hard and fast, but in time, your body will adapt, and your tidal volume will increase with only a minimal increase in respirations (Katch et al., 2015).
Just as there is a gas exchange in your alveoli, there is also gas exchange in your tissues. Because you are running, your muscles need more energy, so they will use up more oxygen. The oxygen will flow into your muscle cells, and carbon dioxide will flow out to be returned to the heart to be delivered to your lungs to be expelled. Your body will keep up and not run out because most people tend to over-breathe to make up for it (Katch et al., 2015).
Like I said before, your body in time is going to adapt beautifully to running. Two adaptation examples are increased respiratory muscle endurance and increased respiratory muscle strength. Your minute ventilation can increase 20-fold from what it is at rest, and your lungs will be able to handle the heavier demands of your training (McKenzie, 2012). As the lung muscles are able to work harder and longer with exercise, you will find yourself running faster and longer. I wish you much success, Meghan.