The heart is the most important organ in our bodies. Without it we cannot live. What can we do to make sure that our heart stays healthy? Can smoking really harm the condition of the heart?
Effects of exercise
As a person exercises, the longer the person exercises the dept of breathing increases as the exercise becomes harder or tiring. Our lungs respond to this by increasing the breathing rate (air inhalation). So, lungs could supply more oxygen from air, which is then transferred from the lungs through alveoli to the blood and then to the muscles via the circulatory system. During strenuous exercise, as the exercise get harder or more tiring, the demands for oxygen cannot be met alone by respiratory organs. During this time 'anaerobic' respiration takes place. This process builds of an oxygen deficit, during which lactic acid is produced. After the exercise, at rest the subject (person) will continue to breathe hard and the heart rate remains the same, until the body has paid back the oxygen debt to the muscles. The oxygen is used to convert the lactic acid back to glycogen.
The aerobic fitness is a measurement of the uptake: transport and use of oxygen by the body. Aerobic fitness is measured by having the subject perform strenuous exercise for example, running on a treadmill and then gradually increase the intensity of the exercise, at the same time taking measurement of the subject oxygen uptake. As the intensity of the exercise increases the uptake of oxygen will also increase. The other way, which is easier to make measurement of aerobic fitness, is to take measurement of the subject heart rate. This is good a indicator, because oxygen is delivered by the circulatory system and each heart beat indicates a quantity of blood being pumped by the heart.
Heart rate is affected by age, gender and fitness level of a person. In young people heart rate is higher than older people. This is because young people can increase their heart rate and deliver large amounts of oxygen to the muscles, which is why they have better aerobic fitness than older people. Older people seem to have lower heart rate, which is a major cause of their reduced aerobic fitness. The other reason for this is that older people generally have less muscle mass and more body fats. This is not necessarily true; a person could improve his/hers aerobic fitness by regularly training their body. By regularly exercising improves the transport of oxygen efficiently within the body. This is because by exercising you train your heart to lower the heart rate- at lower heart rate the heart pumps more blood with every single heart beat. This and other physiological changes like reduction in body fats increase the oxygen transport capability. Thus, I will need to consider these facts in my investigation.
Effects of smoking on the cardiovascular systems
Carbon monoxide inhaled by smokers increases the CO level in the blood. Haemoglobin in the red blood cells helps transport oxygen from heart to rest of the body including working muscle. As CO has greater affinity for haemoglobin than does oxygen, this means that CO from smoking will readily bind with haemoglobin and prevent oxygen from binding to haemoglobin. Also, myoglobin in the muscles works same as the haemoglobin in the blood, thus less oxygen from blood gets to working muscle due CO occupying the haemoglobin and preventing oxygen molecules reaching the muscles. Research shows that smoking reduces maximal oxygen intake known as VO2 Max and causes premature muscles fatigue. Therefore, I find that smokers will have less aerobic fitness than non-smokers. Exercise triggers sympathetic nervous system to release epinephrine and increases heart beat as well as blood pressure. But, nicotine decreases responses to epinephrine.
Smoking and health
Cigarette smoking kills many thousands of people a year, making it the largest preventable cause of death in developed country (National Cancer Institute). Smoking increases the risk of coronary heart disease and heart attacks five times the normal risk. This occurs as a result of atherosclerosis in the lining of the coronary arteries that makes them to become narrow and restrict the flow of blood. This forces the heart to work extra hard to force blood through the coronary arteries and causes blood pressure to rise. Consequently less oxygen and nutrient are supplied to the heart muscle during vigorous exercise.
Cardiovascular diseases are cause of many factors like diet and smoking. Nicotine is one of the major factors that increase the blood pressure by constricting the arteries (Jones 2000 and A/S Biology). This rise in high blood pressure damages the lining of arteries. This damage promotes the development of fatty plaques and blood clot. Making it difficult for blood to flow through the arteries and eventually flow of blood will be completely reduced.
Smoking also increases the risk of emphysema and lung cancer due to build up of tar form cigarette smoke in the lungs. As the diseases emphysema progress the blood vessel in the lungs become more resistant to flow of blood, raising blood pressure in the pulmonary artery. Hence, this reduces the ability of blood to transport oxygen effectively to muscles for respiration to take place.
