Discuss the short term and long-term effects of exercise on the cardiovascular system, the breathing system and the muscles.
Discuss the short term and long-term effects of exercise on the cardiovascular system, the breathing system and the muscles
Exercise is defined as activity that requires physical or mental exertion especially when performed to develop or maintain fitness. During exercise, the cardiovascular system, the breathing system and the muscles work in conjunction with each other in order to perform their tasks more efficiently. A vital process of exercise is respiration. The production of energy. Principally, respiration is the breaking down of oxygen and glucose into carbon dioxide, water and ATP (energy). However, there are two types of respiration. Aerobic respiration requires oxygen and has the ability to break down both fatty acids and glucose. Anaerobic respiration takes place when there is a lack of oxygen, a lactate is formed and fatty acids cannot be broken down.
In this essay I plan to explore the long and short-term effects on these different systems.
The cardiovascular system involves the pulsating heart and flow of blood around the body in order to carry oxygen to the major organs including the muscles and returning the deoxygenated blood to the lungs. The heartbeat, the rate at which the heart pumps blood around the body, changes depending on the amount of physical activity. The average persons resting heart rate is between 60 and 70 beats per minute. However, during exercise the pulse rate increases, this is due to a greater demand for energy in the muscles, therefore a greater rate of respiration and a greater need for oxygen. This has an immediate effect on the amount of blood passing through the heart per minute. At rest, 4-6 litres of blood per minute passes through the heart. At maximal exercise, the cardiac out put increases by up to 22 litres per minute in young males and 15 litres per minute in young adult women. The vascular system also reacts to exercise. In organs such as the kidneys and liver, which are not particularly affected by exercise, vasoconstriction occurs. This means that more oxygen can be deposited in the muscles. Vasodilation also occurs during exercise, arterioles leading to organs vital in exercise. This includes the skin to increase heat loss and the muscles to increase the blood flow, in order to increase aerobic respiration.
The short term effects of exercise on the cardiovascular system are, increased heart rate, which returns to normal after a period of rest and increased blood flow and rapid heat loss which may continue a short while after exercise while arterioles return to normal size. The increased heart rate and blood flow has an immediate effect on the lungs as they can receive up to four times as much blood.
The long-term effects of exercise on the cardiovascular system are a lower resting heart rate than average (bradycardia). Many training athletes have resting heart rates of between ...
This is a preview of the whole essay
The short term effects of exercise on the cardiovascular system are, increased heart rate, which returns to normal after a period of rest and increased blood flow and rapid heat loss which may continue a short while after exercise while arterioles return to normal size. The increased heart rate and blood flow has an immediate effect on the lungs as they can receive up to four times as much blood.
The long-term effects of exercise on the cardiovascular system are a lower resting heart rate than average (bradycardia). Many training athletes have resting heart rates of between 40 and 55 beats per minute. Some athletes have to be fitted with pacemakers because their pulse rates are so low that their hearts have been known to stop. Athletes who train aerobically and run long distances, tend to also have larger hearts, particularly the left ventricle, this is due to the fact that the blood leaves the left ventricle in order to be pumped round the body. Therefore, the left ventricle in particular needs to be stronger in athletes in order to supply the organs with sufficient oxygen at a sufficient rate. The heart size can be increased by up to 40% in some endurance athletes therefore up to 40% increased cardiac output. The increased size in the heart also increases the stroke volume. This means that a larger volume of blood can leave the heart in each beat. The blood volume and contents is also different as an effect of regular exercise. The haemoglobin levels are higher; so more oxygen can be transported.
However, if a person is not physically fit, and they over exert themselves in exercising, too much strain on the heart means it is not so efficient and their endurance and cardiovascular fitness is not as good as athletes in training.
The breathing system involves the inhalation of oxygen and the exhalation of carbon dioxide and water. It also includes the gaseous exchange at the alveolar-capillary surfaces whereby oxygen diffuses into the bloodstream and carbon dioxide diffuses out. As we have already established, during exercise there is an increased need for oxygen. This means that the inhalation and exhalation rates during exercise are increased in two ways. The tidal volume, namely the amount taken in each inspiration and expiration and also the rate of breathing, the number of breathes taken per minutes. The increase between these two figures can be as much as twenty times.
So, an increase in tidal volume on breathing rate means that the amount of oxygen taken in will be directly increased. With more oxygen being inspired, the diffusion rate at the alveolar-capillary exchange surface will need to increase. The increase in diffusion rate in made possible by the increase in blood flow. During exercise, adrenaline is secreted into the blood steam, from the adrenal gland and brings about vasodilation. As well as oxygen and nutrients needing to be supplied to the muscles, waste product such as carbon dioxide need to be removed. Carbon dioxide can also be removed more efficiently from the blood.
The short-term effects of exercise on the breathing system are, shortness of breath and rapid breathing. This occurs in order to replace the oxygen in the blood and remove the carbon dioxide, which has built up during exercise. The internal intercostal muscles and diaphragm are the reasons for this rapid breathing. The intercostal muscles contract more strongly than usual in order to expire carbon dioxide and other waste products more efficiently. The diaphragm also moves upwards in order to increase the expiratory volume. Over exertion during exercise can mean that not enough oxygen is being inspired. A lack of oxygen to the brain can cause the athlete to collapse.
The long-term effects of exercise on the breathing system are; increased lung capacity. Athletes tend to have a larger lung volume than that of a normal person of the same sex and weight. Consequently, the diffusion capacity of the athletes is higher. A larger surface area means than there are more places where gaseous exchange can occur. The amount of oxygen consumed per minute is also higher as a consequence of the increased surface area and rate of diffusion.
The muscles are greatly affected by exercise. In fact, it is the muscles that are the main "tool" used in exercise. The cardiac muscles work hard during exercise to pump enough blood around the body. Other muscles work depending on the type of exercise being carried out.
During exercise the muscles respire in order to produce enough energy to function. The rate of respiration, and overall metabolic rate of cells increases. The muscles gain energy for respiration in a number of different ways. A small amount is stored in the muscles as ATP, but only enough for a burst action like tennis serve. Stored glycogen is broken down into glucose; glycogen in the liver is secreted into the blood as glucose and finally, fatty acid from fat stores are secreted into the blood (fatty acids can only be broken down by aerobic respiration).
Metabolism of energy during and after a sprint
Aerobic Respiration
C6H12O6 + 6O2 6CO2 + 6H20 + energy (2880 kJ)
Anaerobic Respiration
C6H12O6 2CH3CH(OH)COOH + energy (150kJ)
(Lactic acid)
As you can see, aerobic respiration is more produces more energy (20 times more) than anaerobic. As a result of anaerobic respiration, lactate builds up in the muscles.
The short-term effects of exercise on the muscles are fatigue. This means that after continual muscle contraction, the muscles will loose force. When it is difficult or impossible to contract the muscles, then this is termed muscle exhaustion. The short-term effects of anaerobic respiration on the muscles are fatigue after a short while, some pain and an oxygen debt. The oxygen debt is defined as the oxygen needed to oxidise the lactic acid in the muscles. Lactic acid reacts in the same way as carbon dioxide in that it stimulates ventilation system. During exercise, there is an increased blood supply to the muscles. This is in order to increase the oxygen to the muscles to aid respiration. During exercise, the energy stores of glycogen and ATP are lost. These need to be built up again and can be done so over several days.
The long-term effects of exercise on the muscles are; increased muscle size. Over a period of training, the diameter of the muscle fibres can increase; the number of fibres also increases. Athletes tend to have higher metabolic rates than "unfit" people. They have a larger number of mitochondria, which means a greater rate of respiration. This also means that athlete respire more fat than unfit people therefore have a lower fat content in their body and higher muscle bulk. Physical exercise that is directed mainly at working the muscles has a great effect on the strength of the muscle. The more the muscles are exercised the greater their strength. Exercising the muscles increases their size and consequently increases their strength. The more exercise that muscles do, the greater the blood supply. Regular exercise increases the blood vessels in the muscles and consequently increases the supple of energy and oxygen. Finally, regular exercise of the muscles improves movement and coordination between antagonistic muscles. It improves the speed in which muscles are able to relax and contract, as muscles that do not relax quickly enough can be torn. If muscles are under exercised and then are suddenly put under periods over exertion, they can become damaged, sprained or torn. Over exercise, rapid cooling and insufficient salt are all factors that can cause cramp.
In conclusion exercise affects these three different systems in many different ways, however it is important to take into account each individuals personal health, fitness and lifestyle when considering the effects of exercise. For example a young healthy athlete who eat a balanced diet, doesn't smoke and trains regularly is going to have a more effective breathing cardiovascular, breathing and muscular system than a 60 year old obese diabetic who has smoked forty a day since he was 17.
Alice Unwin
09/05/2007
