The next concept—scale, proportion, and quantity—concerns the sizes of things and the mathematical relationships among disparate elements. The next four concepts—systems and system models, energy and matter flows, structure and function, and stability and change—are interrelated in that the first is illuminated by the other three. Each concept also stands alone as one that occurs in virtually all areas of science and is an important consideration for engineered systems as well.
Health effects of exercise Improved general fitness The greatest benefit of a regular exercise program is an improvement in overall fitness.
As discussed above, appropriate exercise improves muscular strength and endurance, body compositionflexibility, and cardiorespiratory endurance. The level of maximal oxygen intake or cardiorespiratory endurance is not by itself of great importance to most individuals.
For example, consider the simple task of walking at a rate of three miles per hour. This task involves an energy expenditure of approximately three times the resting metabolic rate. Extremely unfit individuals may have a maximal aerobic power of only six times their resting metabolic rate.
For such individuals, a three-mile-per-hour walk requires half of their maximal capacity. A middle-aged person who exercises regularly will have a maximal aerobic power 10 to 12 times resting, so the same walk will represent only 25 to 30 percent of maximal capacity.
This example illustrates how any submaximal task is relatively much easier for the conditioned individual. Moreover, a person cannot work throughout the day at much more than about 20 percent of maximal capacity without becoming chronically fatigued.
The deconditioned person who has a maximal aerobic power of six times resting can comfortably sustain a work level of only about 1. This low capability for sustained energy expenditure can support only a very sedentary existence: Individuals who attempt to lead more active lives than their fitness level will support become chronically fatigued.
Persons with adequate or optimal fitness levels, on the other hand, are able to meet the physical demands of an active life relatively easily. One of the most frequent observations made by individuals who have begun an exercise program is that they feel better, and research studies document an improvement in feelings of general well-being in more active people.
Decreased risk of coronary heart disease Coronary heart disease is the leading cause of death in the developed world. Coronary heart disease is defined as myocardial infarctionor heart attack; angina pectorisor chest pain; or sudden death due to cardiac arrest or abnormal electrical activity in the heart.
The basic disease process that underlies coronary heart disease is atherosclerosisa disorder characterized by the accumulation of cholesterol and the proliferation of smooth muscle cells in the linings of the arteries.
This results in a gradual narrowing of the arterial channel, and this narrowing diminishes and may ultimately stop blood flow through an artery. When this occurs in a coronary artery—that is, an artery supplying the heart—one of the manifestations of coronary heart disease occurs. Epidemiological evidence of exercise benefits Studies have linked sedentary living with high rates of coronary heart disease mortality.
One study found that San Francisco longshoremen who worked in jobs requiring high levels of energy expenditure had less risk of dying of heart disease than did longshoremen who performed sedentary jobs. This study showed that dockworkers and cargo handlers expended at least 1, kilocalories more per day than did clerks and foremen and that sedentary workers, during a year observation, were about twice as likely to die from heart disease.
Another study followed the health status of approximately 17, male graduates of Harvard University for many years. All these men essentially had sedentary jobs, but they differed in the amount of leisure time they spent on physical activities.
Men who expended at least 2, kilocalories per week on physical activity had only half the death rate from heart disease as did those men who expended less than kilocalories per week. Not all of this energy was spent in exercise programs; some was expended during routine activities such as climbing stairs.
The effect of exercise on coronary-heart-disease risk factors One of the important medical achievements of the 20th century has been the development of the risk-factor theory of coronary heart disease. Scientists have discovered that persons who are overweight, smoke cigarettes, have high blood pressure, or show elevated blood levels of certain types of fat- and cholesterol-carrying molecules are much likelier to die from coronary heart disease.
Furthermore, combinations of these risk factors result in exponential increases in the risk of death. The discovery and description of risk factors have led to an understanding of the atherosclerotic process and of how to prevent and treat it. Fat and cholesterol are transported by the blood in complex molecules called lipoproteins.
Researchers have identified several classes of lipoproteins and have elucidated their roles in atherosclerotic progression. It is, therefore, possible to describe abnormal, or high-risk, lipoprotein profiles.
Regular aerobic exercise improves the lipoprotein profile in most individuals. Although more work is needed to completely understand this association, the dose of exercise necessary to effect a beneficial change in the lipoprotein profile seems to be about eight to 10 miles of running or its equivalent in other activity per week.
Elevated blood pressure hypertension is a second powerful risk factor for coronary heart disease.Learn about human anatomy and physiology - skeleton, muscles, exercise physiology and theory underpinning sports performance in our easy to read information pages.
The human respiratory system is adapted to allow air to pass in and out of the body, and for efficient gas exchange to happen. Exercise and smoking both affect the lungs and circulatory system. This proposed rule would update the home health prospective payment system (HH PPS) payment rates, including the national, standardized day episode payment rates, the national per-visit rates, and the non-routine medical supply (NRS) conversion factor, effective for home health episodes of.
International Classification of Diseases, Revision 10 () [Return to International Classification of Diseases]. Jun 19, · This article focuses on the use of therapeutic injections (see the image below) to treat acute and chronic pain syndromes.
Discussion of this topic begins with an overview of regional anesthesia, which includes the pharmacology of frequently administered medications and basic information regarding equipment and safety. Exercise - Health effects of exercise: The greatest benefit of a regular exercise program is an improvement in overall fitness.
As discussed above, appropriate exercise improves muscular strength and endurance, body composition, flexibility, and cardiorespiratory endurance. The level of maximal oxygen intake or cardiorespiratory endurance is not by itself of great importance to most individuals.