INTRODUCTION

Exercise science is a large and growing body of knowledge about the acute and chronic effects of physical activity on health, structure and function. A Medline search for ‘exercise’ in the title returns 57,000 scientific journal articles. This discipline has truly come of age and is a key component of any integrative approach to patient care.

EXERCISE DEFINED

Physical exercise involves the voluntary movement of the body, incorporating large muscle groups, with the goal of enjoyment, relaxation and physical exertion to improve the body’s structure and function. The different types of exercise will be discussed shortly, but the avenues for exercise include sport participation, recreational activities such as bushwalking, fitness training such as resistance training, aerobic classes, yoga, Pilates, occupational and recreational work such as gardening, and incidental exercise such as walking to the shops or cycling to work.

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.

FLEXIBILITY EXERCISE

Maintaining range of motion about our joints is also critical at all stages of life, and even more so as we age. Flexibility training involves taking the joints to a position which places the muscles on stretch—that is, they are at or near their maximal length. Holding the muscle at this stretched position when repeated over time causes the muscle to grow longer, which increases its length and results in increased joint range of motion.

MODE AND DOSAGE

The American College of Sports Medicine and the American Heart Association released a combined position stand in 2007. The recommendation on physical activity for healthy adults under 65 years of age is shown in Box 9.2.

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.

INCIDENTAL EXERCISE

While structured exercise sessions are very important in assisting people to meet the minimum recommended physical activity guidelines and in ensuring that all aspects of exercise modes are addressed, the importance of physical activity accumulated during a normal day should also be recognised. Such physical activity is termed ‘incidental exercise’ and recent research has demonstrated considerable benefit for weight control and diabetes management. The overall goal is to accumulate as many minutes each day of non-sedentary time and in particular to reduce the time spent sitting. Importantly, recent research indicates that increasing the time spent standing rather than sitting increases the overall energy usage through the day. Another effective strategy to increase physical activity is to take 5–10 minutes break each hour, stand up and take a walk. This provides benefit by increasing metabolic rate, and work efficiency will probably be improved overall.

There are a myriad ways to increase one’s incidental exercise each day. For example, instead of desperately trying to find a car park close to the bank or shopping centre, park a couple of hundred metres away and walk. Take the stairs instead of the lift or escalator. Walk to your next meeting if it is only down the road, rather than driving or catching a taxi.

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.

EXERCISE EQUIPMENT

Physical activity, or exercise, does not need expensive equipment. Exercise equipment is big business but it is not necessary to have all the latest gear.

Appropriate shoes are vital and help prevent injury. A podiatrist or reputable shoe shop can help the patient select the right shoes. It is also important that they wear flexible, comfortable clothes, such as shorts and a t-shirt, when exercising. If heat or cold are significant factors then clothing should be adjusted accordingly.

Other equipment, such as heart rate monitors and home-gym systems, can certainly be useful, but are definitely not necessary. Most exercises can be done without the need for any additional equipment.

SELECTING AN EXERCISE PROGRAM

There are many ways to be physically active without too much cost or inconvenience. A person might choose to exercise at home or they might prefer the structure and safety of a supervised exercise program. For many people the best option is a mix of exercising at home and a supervised exercise program.

If the patient chooses a supervised exercise program, ask about the level and quality of the supervision provided. Look for a program run by a qualified exercise physiologist. If it is convenient for the patient to exercise in a fitness centre or community facility, try to contact a local exercise physiologist to assess the patient’s level of risk and design an exercise program specifically for them.

Wherever the patient chooses to be physically active, it is important that the GP and the patient consider comfort, health and safety.

WHO TO TALK TO

Exercise physiologists are healthcare professionals specifically trained to give advice on exercise. An exercise physiologist will work with the patient and/or the doctor to ensure an appropriate exercise prescription. Many structured exercise programs will require the patient to seek a medical clearance before starting, and this is advisable.

Before taking part in any exercise program, particularly if the patient has been diagnosed with a chronic illness, it is important for the patient’s GP to discuss the exercise plan with the exercise physiologist. The GP should ensure that they convey any concerns and advise on additional precautions.

WHAT IS A PHYSIOTHERAPIST?

Physiotherapists are trained to assess the underlying causes of joint, muscle and nerve injuries and provide treatment to ensure that people can resume their normal lifestyle as soon as possible.

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.