Exercise as therapy

chapter 9 Exercise as therapy





WHY IS EXERCISE ESSENTIAL FOR HEALTH?


The renowned exercise biologist, Professor Frank Booth, described in great detail the importance of exercise for maintaining normal function and health, in his extensive review of the research literature.1 The basic tenet is that the human genome has not changed appreciably in the past 45,000 years and developed in an environment of high levels of physical activity. While our lifestyles have become predominantly sedentary in our working and leisure environments, our underlying biology expects stimuli involving physical work for extended periods, possibly dawn until dusk, as well as high-force and high-power activities such as would have been required to carry water, children, food, construction materials and tools as well as to run after animals that we sought to kill, or run away from animals desiring to eat us.


Contemporary humans are flying in the face of our genome, which dictates every biochemical process in our bodies. The result is progressive disease and disability from early adulthood, or even earlier in the case of sedentary and often overweight children. Our physical health, apart from injury or infection, is dictated by four interacting factors: genetic predisposition, physical activity, nutritional intake, and environmental factors such as toxins and sun exposure.


Chronic disease is now being described as an epidemic currently accounting for some 70% of our total health burden. This is being driven principally by the three most significant risk factors for chronic disease: tobacco use, inappropriate nutrition and physical inactivity.



EXERCISE TRENDS IN AUSTRALIA AND ELSEWHERE


Despite the strong research evidence indicating that regular physical exercise is essential for human health, rates of sedentary and low exercise levels in Australia remain very high, at around 70% of the population over 15 years of age.2 This has not changed appreciably in the past 10 years despite the best efforts of government and organisations such as the Cancer Council and Heart Foundation to address this societal problem. The rate of no or low physical exercise is higher in females (73%) than in males (66%), and higher in the oldest age group of 75 years and over, at 83%. The rate is lowest in people aged 15–24 years but still frighteningly high at 62%.


The 2007 Australian National Children’s Nutrition and Physical Activity Survey is one of the most extensive investigations of exercise patterns in children aged 2–16 years conducted to date, with some 4487 participants. It was encouraging that most children aged 9–16 years met the Department of Health and Ageing recommendation that children aged 5–18 years accumulate at least 60 minutes, and up to several hours, of moderate to vigorous physical activity every day. According to the survey, there was a 69% chance that any given child would achieve this recommendation. With regard to gender, girls met the guidelines less frequently than boys, both boys and girls were less likely to meet the requirement as they got older, and this drop-off was much higher in older girls.3


Internationally the data are similar for the developed nations; however, physical inactivity levels appear to be increasing markedly in developing countries with modernisation. One trend that is clear throughout the world is the increasing use of screen-based technologies such as television, computers and mobile phones, which appears to have the direct effect of reducing physical activity.



GENERAL HEALTH, QUALITY OF LIFE AND LONGEVITY


The application of exercise for prevention and management of some specific health problems will be described later in this chapter. To establish the importance of exercise for general health, quality and quantity of life, the overall effects of exercise are summarised in Table 9.1.


TABLE 9.1 Effects of regular exercise on health























































Health parameter Effect of regular exercise Preferred exercise mode
Hypertension Reduction of systolic and diastolic blood pressure Aerobic predominantly but some research indicates anabolic also effective
Cardiac function Increased stroke volume and maximum cardiac output Aerobic exercise
Cardiorespiratory fitness Increased efficiency and maximum capacity Aerobic exercise
Haemoglobin Increased Aerobic exercise
Cholesterol Reduces LDL, elevates HDL, lowers total cholesterol and triglycerides Aerobic exercise
Glucose metabolism Glucose tolerance and insulin sensitivity improved Aerobic and anabolic exercise
Bone density Increased bone mineral density, bone mineral content, cortical thickness and fracture threshold Anabolic and ground-based impact exercises (e.g. skipping, bounding, jumping)
Body fat Reduced percentage body fat Aerobic and anabolic combined
Muscle mass Increased muscle cross-sectional area, increased fibre size Anabolic exercise
Strength Increased Anabolic exercise
Physical functioning Gait speed, stair climb, sit to stand, balance, falls risk all improved Anabolic and aerobic exercise
Quality of life Improvement in both general and disease-specific QOL measures Anabolic and aerobic exercise

HDL: high-density lipoprotein; LDL: low-density lipoprotein; QOL: quality of life.


With such beneficial effects one would expect active people to live longer and better-quality lives, and this is certainly borne out in the research.



TYPES OF EXERCISE



AEROBIC EXERCISE


Cardiorespiratory capacity or fitness relates to the ability to perform large-muscle-group, dynamic, moderate-to-high intensity exercise such as walking or cycling for prolonged periods.4 Exercise prescription for cardiovascular fitness is based on mode, intensity, duration and frequency of the activity. The activities prescribed most frequently are walking, cycling, jogging, running, rowing, swimming and hiking. It is suggested that individuals should choose activities that they enjoy and are enthusiastic about continuing, as this will increase program compliance.



ANABOLIC EXERCISE


The other major form of exercise critical to long-term health is anabolic exercise, which is also termed ‘resistance training’ or ‘weightlifting’. This form of exercise involves performing movements against resistance such as barbells, dumbbells, resistance machines or elastic resistance, such that the number of repetitions that can be completed is limited to 12 or less. This is a very important stipulation of intensity. If the movement can be completed more than 10–12 times then the resistance is too light and must be increased. Without such resistance the positive anabolic effects on muscle and bone will not be realised and the hormonal changes that are so neuro-protective will not result.


This concept may seem a little ‘out there’ for people who have not exercised previously or even lifted weights before but the research evidence in support of regular anabolic exercise is huge, demonstrating marked improvements in muscle mass, bone strength, functional capacity and positive effects on mental health and cognitive function. The recommendation of the American College of Sports Medicine is for people aged over 65 years to complete resistance training two to three times per week. The precise prescription is presented in Boxes 9.1 and 9.2.




For healthy adults over age 65 or adults aged 50–64 with chronic conditions, the physical activity guidelines in Box 9.1 are recommended.





ACCUMULATION OF EXERCISE IS THE KEY


One of the most common excuses people provide for their low level of physical activity is that they simply do not have the time. As can be seen in Boxes 9.1 and 9.2, the total commitment required is only 150 minutes of aerobic exercise per week and 90 minutes of strength training. This is less than 4% of a person’s total waking minutes per week. The key is to be flexible in how this is scheduled. Exercise can be undertaken at any time of day or night, and organised into any preferred blocks of effort, with little decrement in health benefit. So whether the patient completes a single bout of 30 minutes of aerobic exercise in a given day or three blocks of 10 minutes, the effect is essentially the same.




GETTING STARTED


The first step on any great journey is often the hardest, and initiating an exercise program can also be daunting. If a person has never been involved in an ongoing exercise program, how to begin, what to expect, whether one is overdoing it or not working hard enough, are all questions the new exerciser faces. For many of us the experience of our bodies responding to exercise with increased heart rate, increased breathing, body temperature rising, muscles aching and the discomfort that can accompany exercise, is foreign and unsettling. For the vast majority these experiences are not harbingers of illness or death. They are the normal adjustments that the body makes automatically to help us perform exercise. Of course if the discomfort is excessive then this is a warning sign, and the person experiencing it should consult their doctor or exercise specialist. Habitual exercisers come to enjoy these changes in their physiology—the sweat, heat and exertion—because they are often associated with positive changes in the brain chemistry and a feeling of exhilaration and success.


If the patient is over 35 years of age or has any primary risk factors for cardiovascular disease such as a family history of heart attack or stroke, high blood pressure, high cholesterol or existing cardiovascular disease, or is overweight, then it is important that they consult their doctor before starting an exercise program.


To begin, it is a good idea to consider seeking expert advice or joining a supervised exercise program. Some insurers provide limited cover for visits to many of these professionals and programs. General practitioners can provide referral to an exercise physiologist as these are the recognised allied health professional for the prescription and monitoring of exercise programs, particularly for people with existing chronic disease.


No matter which option the patients selects, if it has been a while since they have been active it is important to start slowly. Find a routine that suits them. If the person enjoys the activity they are much more likely to stick with it. Whenever possible they should exercise with a friend or relative. Many people find the social aspects of exercise the most enjoyable, and having someone else along also increases safety.








COMPONENTS OF AN EXERCISE SESSION



Warm-up


Warm-up facilitates the transition from rest to exercise; it may reduce susceptibility to musculoskeletal injury by improving joint range of motion, and reduce the risk of adverse cardiovascular events.4 Regardless of training mode, exercise sessions should start with 5–10 minutes of low-intensity exercise incorporating stretching exercises and/or progressive lower-intensity aerobic activity. For example, participants who use 20 kg in a chest press exercise for 12 repetitions might have a warm-up set using 5–10 kg for 15 repetitions before initiating this particular exercise. Similarly, participants who use brisk walking or jogging might conduct a warm-up phase using a slow walk before initiating the training program. Implementing a gradual transition from rest to intense exercise is critical in reducing the risk of an adverse event, such as muscle strain or even a cardiovascular event. The body is much more comfortable with gradual changes in exercise intensity.



Specific phase


Cardiorespiratory training includes 20–60 minutes of continuous or intermittent (minimum of 10-minute bouts accumulated during the day) of aerobic activity training at 60–90% maximum heart rate (MHR) or 50–85% MHR reserve.7 Anabolic resistance exercises include performing 1–4 sets per muscle group training at 50–80% of 1 RM (repetition maximum) or 6–12 RM.7 Flexibility or range-of-motion training includes performing 2–4 sets per muscle group at 30–60 seconds stretching time.7





BASIC PRINCIPLES OF EXERCISE


The aim of this section is to provide knowledge of the basic principles of exercise and in particular aerobic and anabolic exercise. Exercise programs may be implemented in a range of settings and may not always have personnel with qualifications and experience in exercise physiology. The following discussion provides a very basic level of knowledge necessary to understand the principles underlying the exercise programs presented in the later sections of this chapter.



EXERCISE PROGRAM VARIABLES



Adaptation


If a lift in a building were required to lift its maximum capacity from the ground floor to the rooftop each day, it would not increase in its performance and be able to carry more people. It would be more likely to deteriorate—its bearings would wear, the electric motor would become less efficient and performance overall would decline. The human body is a very different machine because it has the ability to respond to a stimulus, such as the work of running or the stress of lifting weights, by altering its structure and function in order to better perform that activity in future. This is termed ‘adaptation’ and is the basis of physical training. A number of points about adaptation must be considered.


First, the body must have a biological mechanism enabling it to make the adaptation. For example, shortening the length of the bones of the upper arm and forearm would greatly increase the amount of weight that could be lifted in the bench press due to increased mechanical advantage, but the body is not capable of this process. Increasing the size of the muscles that perform the bench press would also allow the body to lift more weight and this is certainly an adaptation that is within our capabilities.


Second, the adaptation is very specific to the stimuli—resistance training tends to produce an increase in muscle size, whereas swimming produces an increase in the heart’s ability to pump blood. The concept of specificity will be discussed in more detail later in this chapter.

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Jun 3, 2017 | Posted by in GENERAL SURGERY | Comments Off on Exercise as therapy

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