Data Bases • Custom Term Papers • Free Term Papers • Free Research Papers • Free Essays • Free Book Reports • Plagiarism? Links • Top 100 Term Paper Sites • Top 25 Essay Sites • Top 50 Essay Sites • Search 97,000 Papers @ DirectEssays.com • Search 101,000 Papers @ ExampleEssays.com • Search 90,000 Papers @ MegaEssays.com Free Essays • Term Paper Sites • Chuck III's Free Essays • Free College Essays • TermPaperSites.com • My Term Papers • Get Free Essays • Essay World • Planet Papers	Search Lots of Essays Back to Subjects - Sports & Recreation Benefits of Physical Activity Benefits of Physical Activity The Effects of Physical Exercise on the Human Body The benefits of physical exercise in humans far out weighs the harmful effects associated with exercise. A prescription of physical activity has been known to delay the onset or prevention of many chronic diseases. An improvement in heart function, lower blood pressure and improve functional capacity is noticed after just a few weeks of exercising. Physical activity will also result in an increase of lean muscle mass, promote weight maintenance, increased flexibility, and a generally stronger more fit individual. Conversely, exercise when preformed strenuously or obsessively it can counteract such positive effects. Bringing up some issues like oxidative stresses, injuries, and compulsive exercise disorders. The Cardiovascular response to exercise occurs quite quickly, during exercise oxygen is demanded in the muscles and the body uses more nutrients, metabolic process speed up, more wastes are created, and the body’s temperature increases. With intense exercise hydrogen ion concentrations increase within the muscles and blood this results in an increased pH [16]. A study back in 1976 was done by researchers Hidetaro Shibayama and Hiroshi Ebashi on the effects of long-term physical training of adult men. Shibayama and Ebashi took five healthy males and gave them a routine of a twenty-min treadmill at two-thirds their V02 max for three years, five days a week. After a short while (just twenty weeks) the subjects resting heart rate decreased by five beats a minute, an increase of red blood cell count was shown, and a decrease in average cholesterol levels. Improvement in ventilation efficiency became evident, oxygen intake slightly improved as well, and lactate production decreased. The body’s goal is to allow the system to meet increased demands placed upon it by functioning efficiently such as heart rate, stroke volume, cardiac output, aerobic capacity, and blood pressure levels. Not only does the body begin to adapt in a cardiovascular sense but also exercise has been shown to reduce hypokinetic diseases as well as cardiovascular disease. The heart rate is a measurement of how many times the heart beats in a minute. Physically fit people tend to have a lower heart rate and during intense exercise tend to have lower rates as well. A decrease of heart rate at both rest and at fixed intensity of sub-maximal exercise [7] occurs a few months after an exercise program is begun. One’s heart rate reflects the amount of work the heart must do to meet an increase of demands of the body when engaged in activity. Heart Rate tends to increase proportionally with intensity oxygen uptake [16]. The amount of blood pumped out during systole is called the stroke volume and is less than the end diastolic volume because the ventricles do not completely empty themselves during systole. At all levels of physical activity stroke volume is increased. There is an improvement in ventricular performance with an increase of plasma volume [4] and a faster peak lengthening the rate of the left ventricle during diastole [6]. Training can improve stroke volume but by no more then about 20%. Due to the decreased heart rate an increase of ventricular filling will result and an increase in ventricular volume and thickening of ventricular walls thus allowing an overall increase in blood volume. [3] The volume of blood pumped in a minute is called the cardiac output and is the product of the stroke volume and the heart rate. Cardiac output is the amount of materials being brought to, or removed from, the bodies tissues measured by the volume pumped out per minute. Cardiac output is equivalent to pulmonary blood flow and how the lungs add oxygen to the blood and remove carbon dioxide from it. The overall cardiovascular response to an endurance based conditioning program is an increase of maximal cardiac output (heart rate x stroke volume) [14]. Maximal Oxygen Uptake (liters per minute) is predominately a function of cardiac output. Improvement in VO2 max (maximal oxygen uptake) depends on age and type of training. There is a limited opportunity to improve aerobic capacity, approximately 10-20% improvement has been noted. Therefore, maximal oxygen uptake has a "central limitation"[10]. Analogously, oxygen consumption can be related to how much gas consumed per kilometer in order to maintain a certain speed. The more oxygen that can be delivered to the working muscles, the greater the energy supply needed, so that the body can travel for a determined distance. Exercise science has determined that you achieve specific training adaptations by exercising at various intensities or percent-ages of VO2 max. Oxygen uptake capacity is measured directly. In essence there are three major factors determining maximal oxygen consumption: Cardiac output, The oxygen carrying capacity of the blood, and the amount of muscle and the ability of muscle to utilize supplied oxygen [8]. Blood pressure is the force of the blood pushing against the walls of arteries. In fact, each time the heartbeats, it pumps out blood into the arteries. Blood pressure is greatest when the heart contracts and is pumping the blood. This is called systolic pressure. When the heart is at rest (in between beats), blood pressure levels drop. This is the diastolic pressure. Blood pressure is always given as these two numbers, systolic over diastolic pressures. Usually they are written one above or before the other, such as 120/80-mm. Different actions make your blood pressure go up or down. Studies indicate that regular exercise helps keep arteries elastic keeping blood flowing and blood pressure low. Sedentary people have a 35% greater risk of developing hypertension than athletes do. Studies have shown that high-intensity exercise may not lower blood pressure as effectively as moderate intensity exercise [9]. In one study, for example, moderate exercise (jogging two miles a day) controlled hypertension so well that more than half the patients who had been taking drugs for high blood pressure were able to discontinue their medication [14]. CHANGES IN CARDIOVASCULAR SYSTEM AS A RESULT OF PHYSICAL ACTIVITY Measurement Resting Sub-maximal Maximal Pre program Post program Pre program Post program Pre program Post program CO (L/min) 5.0 5.0 13.5 13.2 16.6 19.1 V02 (L/min) 0.280 0.280 1.485 1.485 2.685 3.150 This data was derived from an experiment done of a healthy 55kg, 45 year old male who was put on an exercise routine and results were recorded. [2] Hypokinetic degeneration is defined as a lack of movement and a decrease of functional capacity of many organs and systems of the body. Examples of this are osteoporosis, a form of bone atrophy where the bone experiences a loss of minerals and proteins. Muscular atrophy is the wasting away of skeletal tissue which causes muscular weakness, a reduced capacity for aerobic metabolism, loss of flexibility, cardiovascular degeneration, with increased heart rate, decreased stroke volume, decrease V02 max, and increase of blood pressure. All of these things can be avoided or put off by exercise. Sacrcopenia which refers to the “vanishing of flesh” where estrogen helps moderate the production of a hormone that helps to develop and promote muscle growth. As the aging process begins estrogen levels decline dramatically. By maintaining a moderate fitness regimen this can be avoided. [12] One of the most common complaints of modern men and women is lower-back pain. Sedentary living, obesity, poor posture, badly designed furniture, and stress all contribute to back pain. An appropriate exercise program focusing on flexibility and strengthening the muscles in the abdomen may help prevent back problems. Exercises that strengthen the abdominal muscles such as partial sit-ups, which maintain the back's normal curve and help support the body's weight, can alleviate stress on the lower back. Cardiovascular disease is a leading killer. Cardiovascular disease refers to a variety of diseases and conditions affecting the heart and blood vessels, high blood pressure, heart disease, and stroke. Accounting for more than 40% of all deaths. Heart disease is the leading cause of permanent disability among working adults. Stroke alone accounts for disability among more than 1 million people nationwide. Almost 6 million hospitalizations each year are due to cardiovascular disease. [18] Physical activity reduces the risk for heart disease and helps reduce blood pressure. People who are sedentary have twice the risk for heart disease of those who are physically active. Unfortunately, many do not achieve the recommended level of physical activity, and more than one-fourth reports no leisure-time physical activity. People who maintain an active lifestyle have a 45% lower risk of developing coronary heart disease than do sedentary people. A recent study reported that moderate dietary changes improve cholesterol levels and so lower the risk for coronary artery disease only when an aerobic exercise program is also followed [10]. Diabetes, particularly type 2, is reaching epidemic proportions. Aerobic exercise is proving to have significant and particular benefits for people with both type 1 and type 2 diabetes; it increases sensitivity to insulin, lowers blood pressure, improves cholesterol levels, and decreases body fat. Regular exercise, even of moderate intensity, improves insulin sensitivity. In fact, studies of older people who engage in regular, moderate, aerobic exercise (e.g., brisk walking, biking) lower their risk for diabetes even if they don't lose weight. Anyone on insulin or who has complications from diabetes must take special precautions before embarking on a workout program [8]. A little exercise is good for you however, a lot is not necessary better. At a particular point the body will say enough is enough and the results can be devastating. If exercise is more exhausting than rejuvenating, this is a sign of an acute case of over training. Exercise may reduce age-related lean body mass and risk for several chronic diseases including coronary artery disease, hypertension, non-insulin-dependant diabetes, anxiety, depression, functional decline and frailty. However, exercise when preformed strenuously is associated with increased production of reactive oxygen species. [11], Overuse injuries, lactic build up and compulsive exercise disorders. Increasing evidence indicates that exercise, especially when preformed strenuously, is associated with muscle damage and inflammation. Avoiding overuse injuries involves allowing your body to adapt to repetitive stress. If a change is made in a training routine the body may show signs of overwork. Increasing training has to be a gradual process, building up in easy stages, allowing recovery days from hard training, and rest days if fatigue or pain set in. For any exercise session, one should always warm-up and warm-down thoroughly. Compulsive exercising or "over exercising disorder" is a common characteristic among those who are victims of eating disorders but is not exclusive. It seems that the sole purpose of exercise is to burn calories and lose weight, it is really much more profound than that. The person is so fearful of gaining weight, exercising becomes compulsive and obsessive. Excessive exercising can lead to excessive sweating resulting in dehydration and even death. Free Radicals are chemically reactive species that increase during exercise as a result of higher mitochondria oxygen consumption and electron transport flux. Free radicals may exert dangerous effects when not detoxified or when produced in excessive amounts. They are able to react with and damage biological components critical for the normal functioning of the cell including nucleic acids proteins, and lipids leading to a condition know as oxidative stress. Free radicals that contain one or more unpaired electrons. An example is the hydrogen atom, with one proton and one electron, free radicals are also found in nitrogen. These are mainly produced in the mitochondria, which utilize most of the oxygen consumed for metabolism and ATP production. This rate increases twenty times during exercise causing bodily harm [11]. Studies continue to show that it is never too late to start exercising and that even small improvements in physical fitness can significantly lower the risk of early death. Simply walking regularly can prolong life in the elderly. Moderately fit people, even if they smoke or have high blood pressure, have a lower mortality rate than the least fit. Resistance training is important for the elderly, because it is the only form of exercise that can slow and even reverse the decline in muscle mass, bone density, and strength. Flexibility exercises help reduce the stiffness and loss of balance that accompanies aging [1]. Conclusively, the benefits of exercise far out weight the negative side effects that are sometimes recognized with exercise. The risk of exercise such as injuries, oxidative stress, and disorders can be avoided with an exercise regime that is personally appropriate. Overtime one will notice many significant gains due to exercise and begin to feel more energetic, youthful, and be able to handle the daily demands of life. People of all ages should be involved in some sort of physical activity in order to maintain a healthy lifestyle. Bibliography: REFERENCES 1. Berger T, Polidori MC, Morrrow J, Evans P, Halliwell B, Frei B. Anti-Oxidant Properties of Vitamin C in Presence of Bleomycin-detectable free iron in cord plasma of preterm infants. J Biol Chem 1997;272:15656-15660. 2. Brooks GA, Fahey T. Exercise Physiology. Human Bioengergetics and its Application. New York: Macmillian, 1984 3. Brooks George A., Fahey Thomas D. Exercise Physiology: Human Bioenergetics and its Applications. John Wiley and Sons, New York. 1984 4. Convertino V.A. Blood Volume: Its Adaptation to Endurance Training. Medicine and Science in Sport and Exercise. 1991;23:1338-1348. 5. DiPietro Loretta, Dziura James. Exercise: A Prescription to Delay the Effects of Aging. The Physician and SportsMedicine 2000;28:77-78. 6. Fagard R., Van de Broeke C., Amery A. Left Ventricular Dynamics Furing Exercise in Elite Marathon Runners. Journal of the American College of Cardiology. 1989;14:112-114. 7. Khosia T., Campbell H. Resting Pulse Rate in Marathon Runners. British Medical Journal: 1982;284:1444. 8. Lamb, David. Physiology of Exercise: Responses and Adaptations. MacMillan Publishing Company. 1984. 9. Lemura L.M., Von Dubillard S.P., Mookerjee S. The Effects of Physical Training of Functional Capacity in Adults. J Sports Med Phys Fitness 2000;40:1-10. 10. Nieman David C. Fitness and Sports Medicine An Introduction. Bull Publishing. Palo Alto, Ca: 1990. 11. Polidori MC, Mecocci P, Cherubini A, Senin U. Physical Activity and Oxidative Stress During Aging. Int J Sports Med 2000;21:154-157. 12. Raloff, Janet. Vanishing Flesh Muscle lose in the elderly finally gets some respect. Science News 1996: 150: 90-91. 13. Shephard R.J. Respiratory Factors Limiting Prolonged Effort. Canadian Journal of Sports Sciences. 1987;12:455-525. 14. Shephard Roy J. Aerobic Fitness and Health. Human Kinteics Publishers 1994. 15. Shibagama Hidetaro, Ebashi Hiroshi. Effects of Long Term Physical Training of Adult Men. Exercise Physiology. 1976;9:433-443. 16. Wilmore Jack H., Costill David L. Psysiology of Sport and Exercise. Human Kinetics Publishing. Windsor, On: 1994 17. Byrne D., McGarrick J., Banks D. Division of Physiology GKT School of Biomedical Sciences King’s College London. http://www.umds.ac.uk/physiology/rbm/cvmenu.htm 18. National Centre for Chronic Disease Prevention and Health Promotion. http://www.cdc.gov/nccdphp/cardiov.htm Word Count: 2126
Copyright © 2005 College Term Papers, INC All Rights Reserved.