8 Scientific Health Benefits of Exercise In Human Body

Health Benefits of Exercise and importance of physical activity is being discussed here.The biologic and psychological benefits ascribed to exercise are extremely diverse and vary substantially with regard to scientific documentation of a causal relationship. Some of these benefits have been definitively established and are achievable by anyone who exercises appropriately.

Other benefits, frequently promoted by exercise advocates, usually do not occur, and at times inappropriate advice has been given that has placed patients at undue risk for exercise-caused morbidity or mortality. As with many other areas of health promotion, enthusiasm to help others by encouraging them to exercise can easily outstrip the scientific basis for such actions. While the idea that exercise might promote health is not new, many of the details regarding specific health benefits and exercise requirements arc still much debated and under investigation.

Here Are Proven Health Benefits of Exercise In Human Body Which Every one Must Know

EXERCISE AND PHYSICAL WORKING CAPACITY

The most effective method of achieving an increase in physical working capacity or “physical fitness” is through a systematic increase in habitual exercise (exercise training). This increase in capacity is an adaptive response by the body to the stress placed on various tissues and biologic functions by the increased metabolic or physical demands of the exercise. If the appropriate type of exercise is performed at the proper intensity, duration, and frequency, sedentary individuals of all ages will achieve significant improvements in physical working capacity. After training, they will be able to exercise at a greater intensity and for a longer duration than before. Also, at the same sub-maximal exercise intensity they will experience less fatigue. This increase in functional capacity is due to enhanced metabolic capacity of skeletal muscle, increased capacity for substrate and oxygen delivery to the muscle, and changes in autonomic nervous system regulation during exercise.

Increases in physical working capacity often are equated inappropriately with improvements in health status or disease prevention. This is an important and often difficult distinction to make: that while a very high level of physical fitness usually requires good health, an improvement in fitness does not ensure an increase in resistance to disease or a reduction in clinical manifestations. For example, patients with disorders such as emphysema, diabetes, or hypertension can significantly increase their working capacity through exercise without necessarily changing the severity of their disease or their medical prognosis. Becoming more physically fit and improving health status are interrelated but not synonymous.

HEALTH BENEFITS OF EXERCISE

Most of the health-related benefits of exercise appear to result from the increase in metabolism required to provide the energy needed for skeletal muscle contraction. This increase in demand for energy triggers a number of adaptations designed to enhance the efficiency and capacity of the skeletal muscle to perform work and minimize fatigue. Adaptations also occur in those systems that support the increased energy requirements of skeletal muscle, including the nervous, endocrine, cardiovascular, respirator)’, and skeletal systems.

CORONARY HEART DISEASE.

The area of greatest scientific inquiry regarding the health benefits of exercise has been its potential role in the prevention of coronary heart disease (CHD). In 1952 J. H. Morris and colleagues published data demonstrating that the conductors on double-decker buses in London developed fewer manifestations of CHD than did the less active bus drivers. Since then it has been repeatedly, but not exclusively, demonstrated that men and women who select more active jobs or leisure-time pursuits tend to experience fewer fatal and nonfatal CHD events. While these studies do not demonstrate a cause and effect relationship, the direction of the association is positive and quite consistent, the magnitude of the differences in CHD events is clinically meaningful, and the amount of exercise performed during leisure-time associated with lower CHD risk is well within the capacity of most clinically healthy adults. As of yet no randomized trial of adequate design has been performed to determine if an increase in exercise by sedentary adults free of clinically evident CHD on entry into the study would significantly reduce future CHD events.

The five controlled clinical trials so far conducted to evaluate the effects of exercise training on recurrent cardiac events in patients following myocardial infarction have yielded statistically negative results. In two of these five studies, the exercise group tended to have fewer events (p < 0.10 > 0.05) and in all of the studies the adherence to exercise training was sufficiently poor to raise questions regarding their adequacy as a test of the exercise hypothesis. TTius, no definitive evidence exists to substantiate that an increase in exercise will reduce either the primary or secondary occurrence of CHD clinical events.

There are several mechanisms by which exercise might act to reduce CHD risk. Exercise might maintain or increase oxygen supply to the myocardium by decreasing the progression of atherosclerosis, increasing coronary collateralization, or enlarging the diameter of proximal coronary arteries. Only preliminary evidence has been published documenting that any of these changes occur in man. Several studies have demonstrated potentially beneficial blood dotting-fibrinolysis activity and altered piasma lipoprotein profiles following training. These changes might improve the coronary blood flow in some individuals.

In contrast to very little evidence for any exercise-induced increase in myocardial oxygen supply, there is unequivocal evidence that endurance exercise training decreases myocardial oxygen demand. This decrease in demand is achieved primarily by a decrease in heart rate at rest and decreases in heart rate and systolic blood pressure during submaximal exercise. These changes are most likely produced by a modification in central nervous system regulation of cardiovascular function (decreased sympathetic and increased parasympathetic drive) and an increase in blood volume, with little, if any, change occurring in intrinsic mvocardial function.

CARBOHYDRATE METABOLISM.

A potentially important and often unrecognized health benefit of exercise is its effect on carbohydrate metabolism. During large muscle, dynamic exercise of moderate intensity, the glycogen stored in skeletal muscle is used for the production of energy and becomes partially depleted. For the next 24 to 72 hours this glycogen is replaced by the uptake of glucose from the blood. In addition to this acute effect of increased glucose removal, there also is a more chronic training effect that increases the sensitivity of insulin receptors in skeletal muscle and adipose tissue and thus the rate of glucose removal at any given level of plasma insulin. This “insulin sparing” effect of endurance exercise training probably decreases the long-term insulin production requirements of beta cells and may reduce the risk of insulin deficiency developing with increasing age.

OSTEOPOROSIS.

The bone mineral loss that occurs with aging is accelerated by inactivity, especially bed rest. While exercise will not prevent all of this loss, it appears to provide some benefit. For example, in a survey of 59 postmenopausal women, level of habitual activity was one of the major determinants of bone mass as measured by computerized tomography scanning. In the more active women, arm and leg bone mass was greater after accounting for the effects of age, body weight.and calcium intake. Also, when 18 elderly women exercised 3 times per week for 30 minutes each session, an increase in bone mineral content was observed (2.3 per cent), while 12 women who remained sedentary during this time showed a decrease of 3.3 per cent (p < 0.005). These experiences support the use of exercise requiring the movement of body weight against gravity as part of a comprehensive program of osteoporosis prevention.

WEIGHT CONTROL.

More physically active individuals tend to weigh less than their sedentary counterparts and at any given body weight have a greater muscle mass. Even though calorie consumption frequently goes up when sedentary people substantially increase their exercise, they usually experience some adipose tissue loss. In addition to the increase in calones expended during the exercise, there is some evidence that resting metabolic rate is increased for an extended period after exercise, and with a higher percentage of body weight being muscle mass. Basal metabolic rate at any given body weight may also increase. For these reasons, exercise, along with proper nutntion, can improve health status by contributing to the maintenance of optimal body composition.

PSYCHOLOGICAL STATUS.

Many physically active people state that the major health benefit that keeps them exercising is their improved psychological status. They report less anxiety and depression, more self confidence, and an increased ability to cope with at-home and job-related stress. How frequently such benefits will occur when sedentary people take up exercise is not known, nor is there any understanding of how to design an exercise program to maximize the positive psychological effects. Whether or not a biologic basis rather than just a “situational basis” exists for improvements in psychological status has not been established. Proposed explanations for a biologic basis are the decrease in circulating catecholamines produced by exercise training and/or the acute increase in beta-endorphins that occurs during and following vigorous exercise. Regardless of the mechanism, consideration should be given to getting sedentary people up and away from chronic stress-producing environments and having them participate in an exercise of their choice.

OTHER DISORDERS.

There are a number of other situations in which patients with an established disease tend to show some clinical improvement if they exercise properly, but there is no good evidence that exercise prevents these disorders. Diseases included in this category are chronic obstructive lung disease (emphysema and bronchitis), mild or labile hypertension, and intermittent claudication. There are no data supporting the notion that exercise prevents any infectious disease. More active people have a greater morbidity and mortality from accidents than would be the case if they remained sedentary!

A Comment on Safety

When recommending exercise for health promotion, one does battle with the proverbial two-edged sword. Inappropriate exercise literally can pose dangers to limbs and life. The most commonly encountered problem is that of musculature discomfort or injury due to trauma or overuse. Of more severe consequence, but much less frequent, is the precipitation of a major cardiac event, usually ventricular fibrillation. However, the likelihood is remote that exercise will cause a cardiac arrest in individuals without underlying cardiac disease.

There are many other health risks of exercise, but these usually are limited to individuals with established disease (e.g., diabetes, asthma, or renal failure) or occur with very extended or competitive exercise. The most important of these risks is the development of severe heat injury’ (Ch. 564) The total prevention of these injuries cannot be achieved if adults are to increase their exercise, but the risks can be reduced by proper medical evaluation, individualized exercise recommendations, and improved public education.

AN EXERCISE PLAN FOR HEALTH

The type of exercise that provides the greatest health benefits and permits the greatest increase in energy expenditure with the least fatigue consists of performing rhythmical contractions of large muscles to move the body over a distance or against gravity. Such exercise frequently is referred to as being endurance or “aerobic,” since, if it is performed at an intensity that is moderate relative to the person’s capacity, most of the re-synthesis of high energy compounds in the muscle is performed in the presence of oxygen. Included in this type of exercise is walking, hiking, jogging or running, cycling, cross-country skiing, swimming, active games and sports, selected calisthenics, and vigorous at-home or on-the-job chores. While very specific activities may be required when training for athletic competition, for health purposes any exercise of this type seems to be of benefit if performed frequently enough at the proper intensity.

The exercise-induced changes that contribute to health are achieved when the exerase intensity is somewhat greater than that usually performed by the individual. This increased intensity or overload causes adaptations that allow the metabolic needs to the muscles during exercise to be more readily met. While exercise intensities that are even slightly greater than that usually performed will produce changes, the usual recommendation is that exercise for optimizing health should be performed at 50 to 75 per cent of the individual’s oxygen transport (aerobic) capacity or at 60 to 85 per cent of maximum achievable heart rate during exercise. Using these guidelines, exercise training heart rates for individuals 30 years of age would range from 114 to 162 beats per minute, whereas at age 60 the range would be from % to 137 beats per minute. For most people this recommendation produces a substantial intensity overload, since they usually do not exercise at more than about 45 per cent of their aerobic capacity during everyday activities.

The exercise duration to be recommended will depend on the person’s health or fitness goals and exercise capacity as well as on the type of exercise being performed. One interpretation of the data available on exercise and health is that people who do even a little bit of exercise on a regular basis are better off than those who do almost nothing. A reasonable goal seems to be an energy expenditure over usual activities of approximately 300 kiiocalories per session with a frequency of at least every other day. Most clinically healthy adults have the capacity to expend from 400 to 700 calories per hour while performing activity of moderate intensity; thus they can expend 300 kilo-calories in 25 to 45 minutes. Activities meeting this goal include walking or jogging 4 kilometers, cycling or swimming for 30 minutes, or playing several sets of singles tennis lasting for 45 minutes. While lower intensity exercise such as walking or gardening will not produce a large increase in exercise capacity, if performed for longer periods or more frequently, it seems to provide many of the health benefits derived from more vigorous exercise (e.g., facilitates weight control, bone mineral retention, etc.).

CONCLUSION About Health Benefits of Exercise.

Inactivity does not appear to be the sole cause of any major disease, but a physically active lifestyle improves general health status and retards some of the functional impairments that frequently occur with aging. Success in initiating and maintaining an exercise program is most likely to occur when it is individually designed and takes into account the person’s goals, interests, skills, and exercise opportunities, as well as exercise capacity. Instructions should be given to set aside a time for exercise and to fill it with a variety of activities, rather than selecting a single activity as the sole basis for increasing exercise for health purposes. The exercise plan should be convenient to perform, fit within the general lifestyle of the individual, and be considered fun or at least enjoyable. Success at exercise is increased when the individual has acquired the knowledge of what is to be done and why, the confidence that success can be achieved, and the patience to wait for the benefits to accrue.

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