Exercise is being increasingly recognised to play an important role not only in the prevention but treatment as well of multiple lifestyle diseases (chronic diseases), health conditions and risk factors associated with these. In view of the above, exercise is now aptly being recognised as medicine. It is the cornerstone of lifestyle modification to achieve Holistic Health. However, like any other medicine, exercise too has some associated risks, though benefits of exercise on health, far outweigh the risks. However, before proceeding with the benefits and risks associated with exercise, it would be pertinent to understand some important related terms. Even though physical activity and exercise are often used interchangeably, they are not synonymous. The definition of these and some closely related terms are given below:
WHO defines physical activity (PA) as ‘any bodily movement produced by skeletal muscles that require energy expenditure’ – including activities undertaken while working, playing, carrying out household chores, travelling and engaging in recreational pursuits. Physical activity broadly encompasses exercise, sports, and physical activities done as part of daily living, occupation, leisure, and active transportation.
It is a subcategory of physical activity that is ‘planned, structured, repetitive, and aims to improve or maintain one or more components of physical fitness’.
It is the ability to carry out daily tasks with vigour and alertness, without undue fatigue, and with ample energy to enjoy leisure time pursuits and to meet unforeseen emergencies. Physical fitness can be said to be a sum total of various elements, which are further subdivided into health-related and skill-related components.
Health-related components of physical fitness
Cardiorespiratory endurance (aerobic endurance)
Commonly known as aerobic endurance. The first word in the term, i.e. ‘cardiorespiratory’ is derived from two vital organ systems viz. cardiovascular (also called circulatory system and made up of heart, blood vessels, and blood) and respiratory (made up of lungs and air passages) systems. In the context of physical fitness, the primary role of both these systems is to supply various nutrients, including oxygen, to the muscle cells and other body cells and rid these cells of waste products. The second word in the term, i.e. ‘endurance’ refers to the ability to sustain the effort. Taken together, the term cardiorespiratory endurance denotes the body’s ability to sustain the effort, which hinges on the fitness of the cardiovascular and respiratory systems. In simpler terms, cardiorespiratory endurance can be described as the ability of the cardiovascular and respiratory systems to supply oxygen and other nutrients during sustained physical activity. Since cardiorespiratory endurance training, by strengthening the heart and the lungs, improves the body’s utilization of oxygen, the term aerobic endurance is another term used for cardiorespiratory endurance (aerobic literally means ‘in the presence of oxygen’).
Muscular fitness is an individual’s combination of muscular strength and muscular endurance.
- Muscular strength – it denotes the ability of a muscle to exert force.
- Muscular endurance – it denotes the ability of a muscle to continue to perform over a sufficient time period without fatigue.
It denotes the range of motion available at a joint or the ability of your joints to move freely.
In the context of physical fitness, body composition denotes the relative amounts (percentages) of fat, bone, water and muscle in the human body. The composition of the human body and the methods to analyse it have been discussed in detail in the post what is obesity?
Skill-related components of physical fitness
Skill-related components of physical fitness include agility, balance, power, speed, coordination and reaction time. These skill-related components of physical fitness contribute to your ability to successfully participate in sporting activities. In view of the same, these are sometimes referred to as ‘sports-related’ fitness components. However, they are also useful in older adults, to improve or maintain physical function and to decrease falls. . Detailed discussion on these is beyond the scope of this post.
Physical activity is directly related to physical fitness.
Physical function is defined as the capacity of an individual to carry out the physical activities of daily living (ADL). Physical function is of critical importance for maintaining the quality of life. Actions and activities associated with physical function can be broadly divided into basic activities of daily living consisting broadly of self-care tasks and instrumental activities of daily living (IADL), which though not necessary for fundamental functioning but are instrumental in the life of an individual to live independently in a community.
Examples of basic ADL include:
- Bathing and showering
- Personal hygiene and grooming (e.g. brushing teeth, combing/styling hair)
- Toileting (being able to get on and off the toilet and perform personal hygiene functions.
- Ambulation (walking, going up and down the stairs).
- Transferring (getting in and out of bed/chair/car etc).
In brief, basic ADL are activities that people do when they get up in the morning and get ready to go out of the house – get out of bed, go to the toilet, bathe, dress, groom, and eat.
Examples of IADLs include:
- Meal preparation
- Managing money
- Shopping for groceries and necessities
- Doing laundry
- Using telephone
Adequate physical functioning is important for participation in social, vocational, and recreational activities. If an individual is unable to meet the physical demands of any of these activities, quality of life will be diminished. Limitations in physical functioning not only adversely affect the quality of life and independence of older persons (or those suffering from chronic diseases) but also increases the risk for morbidity and mortality.
Physical inactivity denotes a level of activity less than that needed to maintain good health.
Sedentary behaviour is an attribute distinct from physical activity; it is characterised by activities that involve little or no movement or physical activity. Examples include sitting, watching television, playing video games, using a computer and desk jobs, including studying.
Adverse effects of sedentary behaviour on health
The advent of industrialisation, urbanisation, and mechanised transport has reduced physical activity when compared to the past, even in developing countries. A paper titled ‘Worldwide trends in insufficient physical activity from 2001 to 2016: a pooled analysis of 358 population-based surveys with 1.9 million participants’, authored by four World Health Organisation experts was published in the medical journal ‘The Lancet’, which is among the world’s oldest, most prestigious and best known medical journals, in Sep 2018. According to the study, in 2016 more than one in four adults globally (28% or 1.4 billion people) were physically inactive. However, this can be as high as one in three adults inactive, in some countries. Women were less active than men, with an over 8% difference at the global level (32% women vs. 24% men). Levels of physical inactivity were also found to vary with the economic development of the countries; prevalence in 2016 was more than twice as high in high-income countries (37%) compared with low-income countries (16%). Dr Regina Guthold, the lead author of the study warned – “Unlike other major global health risks, levels of insufficient physical activity are not falling worldwide, on average, and over a quarter of all adults are not reaching the recommended levels of physical activity for good health.” However, what is of greater concern is that as children move through adolescence, they become far less active; more than 80% of the world’s adolescent population is insufficiently physically active. Again, as in adults, adolescent girls were less active than adolescent boys, with 84% vs. 78% not meeting WHO recommendations.
The drop in physical activity is partly due to inaction during leisure time and sedentary behaviour on the job and at home. As highlighted above, an increase in the use of mechanised transportation has further contributed to the reduction of physical activity. Various studies have shown that prolonged periods of sitting or engaging in other sedentary behaviours has been found to be associated with deleterious health consequences even among individuals who meet the current physical activity recommendations. Studies have shown that sedentariness is independently associated with greater risk for death worldwide. It is also a key risk factor for the development of various lifestyle diseases such as cardiovascular diseases, cancer and diabetes. This is of concern from a public health point of view as studies have revealed that more than 50% of an average person’s day is spent in sedentary activities such as watching television and computer use.
However, high levels of physical activity, and/or breaking sedentary activities by short bouts of physical activity or standing, attenuates these adverse effects on health. Therefore, while it is important to be sufficiently physically active, at the same time it is equally important to reduce sedentary behaviours.
Health benefits of physical activity and exercise
Regular physical activity and exercise have been convincingly shown to provide numerous physical and mental health benefits. The health benefits of physical activity are derived through its favourable influence on various health-related components of physical fitness including body composition, cardiorespiratory endurance and muscular fitness. Each component of physical fitness favourably influences some aspect of health. Some of the major health benefits of physical activity are as under:
Health benefits of aerobic endurance
Reduced all-cause premature mortality
All-cause mortality means all of the deaths that occur in a population, regardless of the cause. Regularly engaging in physical activity has been shown to reduce the risk of premature death from all causes, including from coronary artery disease. These benefits also accrue when an individual increases physical activity by changing from a sedentary lifestyle or a lifestyle with insufficient levels of physical activity to one that achieves recommended physical activity levels.
Protection against diseases
Regular physical activity protects against the development of coronary heart disease, stroke, type 2 diabetes, metabolic syndrome, and some forms of cancer (e.g. colon and breast cancer).
Reduces risk factors for cardiovascular diseases
- Reduces blood pressure
- Increases high-density lipoprotein (good cholesterol) and decreases triglyceride levels in the blood.
- Reduces total body fat as well as metabolically more active intra-abdominal fat.
- Enhances insulin sensitivity and thereby improves glucose tolerance.
- Reduces the tendency of blood platelets to clot by reducing blood platelet adhesiveness and aggregation.
- Reduces C-reactive protein, a blood test marker for inflammation in the body. Role of low-level inflammation in the causation of various diseases, including cardiovascular diseases, has been discussed briefly in the post Is obesity a disease?
Blood to the heart muscle is provided by the left and right coronary arteries which branch into increasingly tinier vessels to cover the whole of heart. In humans, very small hair-like vessels called capillaries often interconnect the network of coronary arteries. However, these capillaries are not capable of ‘transferring’ an adequate amount of blood from one coronary artery network to the other, in case of a blockage in any of the coronary artery or its branches.
Under “stress” the inner layer of these capillaries gets stimulated and start the process of enlarging from capillaries into ‘collateral’ vessels, which act as the heart’s back-up system. In an emergency, they ‘bypass’ the blockages in any of the coronary arteries or its branches, and carry significant blood supply to the affected areas of the heart. This serves a function similar to the heart bypass surgery; therefore these collateral vessels can be called “natural bypasses”. The extent to which these natural bypasses form in a person depends on hereditary factors, degree of physical activity, and the existence of narrowing in the coronary arteries due to atherosclerosis.
In response to aerobic endurance training, blood flow through the coronary arteries is increased dramatically and the resultant stress on the capillaries stimulates them to convert into collaterals when the stimuli are repetitive and persist over time. Thus aerobic endurance training often called ‘collateral training’, is a great way to form natural bypasses, that people can apply by themselves, for themselves, provided they are aware of it. Growing new collateral vessels reduces the chances of angina pectoris (chest pain owing to the inadequate blood supply to the heart), myocardial infarction (heart attack) and death. However, a little bit of exercise won’t do the trick; you need to push your heart. Any activity that increases your heart rate sufficiently and is maintained for 20 to 30 minutes and repeated 3 to 5 times a week will do.
As part of the cardiac rehabilitation program, reduces morbidity and mortality in patients with CVDs
Cardiovascular diseases (CVDs), are the world’s leading global killer – taking the lives of 17.9 million people every year, 31% of all global deaths. Of these deaths, 85% are due to heart attack and stroke. Increased physical activity has been found to benefit these patients and is important in the treatment of patients with CVD. A look at the risk factors for CVDs would clearly show that acute interventions, including drug therapy, coronary artery bypass graft surgery and angioplasty do not attack the underlying causes of the disease. Unless patients make important lifestyle changes, these are simply palliative (a drug or medical treatment that reduces pain without curing the cause of the condition) measures for treating CVDs. Only a lifestyle change can do that and exercise is the cornerstone of a multifaceted plan for preventing and reversing CVDs. The importance of exercise as both prevention and treatment for the various CVDs is not a new discovery. In 1772, William Heberden, the English physician who described angina pectoris, remarked that he had “little or nothing to advance…” for the treatment of angina but did know of one patient who set himself a task of sawing wood for half an hour every day and was nearly cured.
Physical activity and exercise are important components of cardiac rehabilitation after a cardiac event to prevent another. Several studies have shown that the most important benefit of exercise training in patients who participate in cardiac rehabilitation exercise training, along with measures to reduce other cardiovascular risk factors, following myocardial infarction (commonly known as heart attack), is a significant (20 to 30%) reduction in all-cause mortality as well as death caused by myocardial infarction. Other benefits include –
- Reduction of symptoms (angina, dyspnea [shortness of breath], fatigue).
- Reduction in nonfatal recurrent myocardial infarction.
- Improvement in exercise tolerance and ability to perform activities of daily living.
- Improvement in psychological well-being and health-related quality of life.
The benefit of exercise for heart disease patients continues to be rediscovered and its utility has extended to sicker patients, such as those with congestive heart failure.
Improves Bone health
Exercise preserves bone mass and reduces the risk of falls (by improving muscular fitness and balance), and resultant injuries such as hip or vertebral fractures, especially in older individuals. It will be discussed in detail in next section.
Improves functional health
Functional health means ability to perform all of one’s activities of daily living. A better functional health promotes participation in occupational, recreational and sports/fitness activities. By prevention or mitigation of functional limitations in older individuals, physical activity and exercise promote independent living in older individuals. It will be discussed in details in next section.
Improves mental health
Exercise reduces anxiety and depression; it improves cognitive function and is associated with a lower risk of cognitive decline and dementia.
Improves general well-being and quality of life
A physically active lifestyle enhances feelings of energy, well-being and quality of life.
Health benefits of muscular fitness
For most people, the term ‘exercise’ means aerobic activities like walking, jogging etc. The benefits of muscular fitness (i.e. muscular strength and endurance) are either overlooked or at best minimized to that of building muscles and improving sports performance. However, scientific evidence now clearly establishes the health benefits of enhancing muscular fitness, which is on par with aerobic fitness, if not more. Muscular fitness becomes even more important with ageing, as muscle mass and strength start declining after you reach your 50s and beyond. The major benefits of muscular fitness are as follows:
Augments and/or preserves muscle mass and function
One of the major function of the skeletal muscles is voluntary movement control needed to perform a wide range of activities – from sporting activities to activities of daily living. Ability to perform these functions is a principal determinant of the quality of life.
Starting from birth till about 30 years of age, in general, muscles grow larger and stronger. But at some point in your 30s, you start to lose muscle mass and function. This age-related loss of muscle mass and function is known as sarcopenia in medical terminology. The reported changes in muscle mass and function are relatively small until about 70 years of age when the loss accelerates. Till about 70 years of age, strength declines by 10% to 15% per decade; after 70 years of age, the rate accelerates to 25% to 40% per decade.
Sarcopenia increases the risk of several adverse outcomes on health; most obvious being physical function limitations (difficulty in performing basic and instrumental ADL) and consequent disability and loss of autonomy, poor quality of life and death. According to a study titled ‘Health Outcomes of Sarcopenia: A Systematic Review and Meta-Analysis’ published in the journal PLOS One, in Jan 2017, the risk of mortality in sarcopenic patients is up to 4 times higher compared to non-sarcopenic subjects. Sarcopenia is also an important causative factor for frailty (a distinctive health state related to the ageing process in which multiple body systems gradually lose their in-built reserves, resulting in increased vulnerability for poor health outcomes, including falls, incident disability, hospitalisation and mortality). All these conditions lead to higher hospitalisation rates, need for long-term care and higher health-care costs in the older people.
In view of the above, it is important to prevent or postpone as much as possible the onset of this condition, to enhance survival and to reduce the demand for long-term care. The major risk factors for sarcopenia include age, gender and physical inactivity. Of these age and gender are non-modifiable and inevitable risk factors. Thus, physical activity has a major role in both prevention as well as management of sarcopenia. In physical activity, strength training (resistance exercise) is particularly effective for slowing the age-related loss of skeletal muscles; just doing aerobic exercise is not adequate. Individuals who have had an active lifestyle throughout their life have more lean body mass (muscle mass) when aged. For people in their 50s and beyond, strength training is crucial to preserve physical function, i.e. the ability to perform the most ordinary activities of daily living, so as to maintain an active and independent lifestyle. What’s more, strength training workouts also improve balance in addition to muscle strength. The improved strength and stability reduce the likelihood of falls, which can lead to fractures.
Slows down bone loss
As with the loss of muscle mass, with age bones deteriorate in composition, structure, and function, which predisposes to osteoporosis (a condition in which bones become weak and brittle). Physical inactivity and inadequate nutrition add to this process of bone loss. On average, after 40, we lose bone mass at an average rate of 1% per year. As bones grow more fragile, they become susceptible to fractures; they are more likely to break after even a minor fall or a far less obvious stress such as bending over to tie a shoelace. Bones of the hips, spine and wrists are most likely to fracture.
Numerous studies have shown that resistance exercises that enhance muscle mass and strength, also increase bone mass and bone strength of the specific bones stressed as a result of tugging and pushing on the bone that occurs during strength training. This stress on bones provides the mechanical stimuli or ‘loading’ necessary to stimulate extra deposits of calcium and nudge bone-forming cells to produce new cells. Thus strength training can not only play a role in slowing bone loss but as several studies show, it can even build bone. This is of great help in preventing osteoporosis.
Though weight-bearing aerobic exercises like walking or running can help improve bone health, there are certain limitations. Firstly, as highlighted above, a certain amount of loading is required to stimulate extra deposition of calcium and new bone cell formation. Therefore, only higher impact activities such as jogging or fast-paced aerobics will have a marked effect on bone health and not the lower-impact, leisurely done aerobics. Secondly, only those specific bones that are stressed during an exercise will benefit. Therefore walking or running protects only the bones of the lower limb and hips. In contrast, a well-rounded strength training program that works out all the major muscle groups will help strengthen practically all of the bones.
Improved body composition and maintenance of healthy weight
As discussed in the section on obesity, muscles are a highly active metabolic organ which contributes the second highest to the resting metabolic rate (RMR), almost 18% of the RMR. An increase in muscle mass as a result of regular strength training raises the RMR, which translates into a daily increase in total energy expenditure. This means you burn more calories, even while you are sitting or sleeping. The increased energy output helps in decreasing body fat in the long term. The combined increment in muscle mass and decrement in body fat helps improve body composition when following a regular strength training program.
While strength training does not burn as many calories as the same amount of time doing aerobic activities such as running, but it does have a significant amount of ‘afterburn’. Strength training exercises are basically anaerobic exercises. The term aerobic literally means ‘with oxygen’ while anaerobic means ‘without oxygen’. While during aerobic exercise, oxygen supply is enough to ‘fuel’ the body’s energy requirements, during anaerobic exercise, which consists of brief, intense, bursts of physical activity, such as weight lifting and sprints, oxygen demand surpasses oxygen supply. To meet such short term emergency requirements of energy, the body uses energy stored in the muscles, in the form of glycogen. Nobel Laureate Archibald Vivian Hill and colleagues described energy metabolism during physical activity and recovery, in financial terms. The energy stored in the muscles was compared with energy ‘credits’. Therefore expanding stored credits (i.e. energy) during physical activity incurs an energy ‘debt’. To pay off this debt, during recovery body continues to use oxygen at a higher rate than before the exercise began, to enable the body to replenish the energy stores as well as restore various bodily processes/systems to resting state. This sustained oxygen consumption is known as ‘excess post-exercise oxygen consumption’ (EPOC); commonly known as afterburn.
EPOC also means that energy is also being expanded at an elevated rate during recovery. The greater the energy deficit or use of available stored energy credits, the larger the energy debt and consequently longer this ‘afterburn’ lasts. In simple terms, the more strength training you do, the more calories you can burn even after the workout is over. Therefore EPOC plays a supplemental role to an exercise in weight management. High-intensity interval training has a more pronounced effect on EPOC.
Management and treatment of type 2 diabetes
Exercise is considered a cornerstone of treatment for type 2 diabetes, alongside diet and medication. Although the effectiveness of exercise in improving blood sugar control is well documented, there is less certainty about the relative effects of different types of exercise. However, recent evidence suggests that strength training is as effective as aerobic training in the management and treatment of type 2 diabetes. In patients who do not suffer from this condition, strength training reduces the risk of developing type 2 diabetes by improving the body’s sensitivity to insulin and improving blood sugar control.
As highlighted in the section on obesity, as many as 80 to 90 per cent of individuals with type 2 diabetes are reported to be overweight or obese; mainly abdominally obese. As there is a very high predisposition for insulin resistance in this population, there is added relevance for strength training in individuals who are overweight/obese. Also, many overweight/obese patients have mobility problems, peripheral neuropathy, visual impairment or cardiovascular diseases. For these patients, it may be difficult to achieve the required volume and intensity of aerobic exercise and strength training may be a more feasible option for these patients.
In view of the compelling evidence supporting the effect of strength training on diabetes, the American Diabetes Association recommends that people with diabetes should do at least two strength workouts a week. However, most guidelines recommend both aerobic and strength training for people with type 2 diabetes, for better protection.
Improves cardiometabolic risk factor profile
In addition to improving insulin sensitivity and glucose tolerance, strength training has also been associated with improvements in various cardiometabolic risk factors including improvements in lipid profile (decreased LDL cholesterol, decreased triglycerides and increases in HDL cholesterol) and blood pressure in individuals with mild or moderate hypertension. In view of the favourable effects of resistance training on body composition, insulin sensitivity, blood sugar control, lipid profile and hypertension, resistance training may be effective for prevention and treatment of metabolic syndrome, a cluster of the most dangerous risk factors for heart attack.
However, despite the well-known independent value of strength training programs for cardiometabolic health, strong evidence exists to confirm the superiority of combined aerobic and strength training regimens over either modality individually.
Reduced mortality risk
Higher levels of muscular fitness is associated with a lower risk of all-cause mortality, fewer cardiovascular disease events, and lower risk for nonfatal diseases.
Reduces pain and disability in individuals with osteoarthritis
Osteoarthritis (OA) is the most common form of arthritis affecting millions of people worldwide. It is a degenerative condition of joint cartilage (a firm rubbery material that covers the ends of bones where they come together to form joints, allowing bones to glide over each other with very little friction) and the underlying bone, seen more commonly in people of middle age and older. Most commonly affected joints are the knee, hip and hand.
A higher level of muscular fitness has been found to be effective in both the prevention and treatment of osteoarthritis. Strong muscles better support and protect your joints; when strong muscles contract, they take the pressure off the joints, in the process reducing wear and tear on the joints and easing pain and stiffness. For instance, the greater quadriceps muscle (a group of 4 muscles located in the front of the thigh) strength reduces cartilage loss in the knee. Without strong quadriceps, the joint bears the brunt of the impact from walking, running or other weight-bearing activities.
Strength training, especially in combination with flexibility exercises, improves muscular fitness and range of motion in the joints and muscles, enabling you to bend and reach with greater ease. A combined effect of these is better functional health (ability to walk, climb stairs etc.), reduced pain and better quality of life. Strength training benefits people with rheumatoid arthritis (a chronic inflammatory disorder affecting joints) too since muscle weakness is common among those with this illness. Strength training has also been shown to be effective in the treatment of chronic back pain and improving posture.
Reduce fatigue and increase vigour
Strength training program for improving local muscular endurance is beneficial for reducing fatigue during activities of daily living.
Prevent/improve depression and anxiety
By improving functional health, which can boost confidence, alleviate dependence on others and open up new options for pleasurable activities, strength training may help with mild to moderate depression. Combining exercise with therapy or with both therapy and medication may yield the best results.
Supportive therapy for cancer patients
Despite advances in the treatment of cancer, patients suffer a wide range of side effects including fatigue, weight changes (including unintended loss or gain), impaired physical function, loss of appetite, impaired sleep and emotional distress, which have an adverse effect on the quality of life. Research studies have shown that strength training has been effective in improving muscular strength and endurance in cancer survivors.
The role of strength training following surgery for breast cancer has been controversial. During breast cancer surgery (mastectomy or lumpectomy) some of the lymph nodes in the underarm (called axillary lymph nodes) may be removed to find out whether cancer has spread to the lymph nodes under the arm. The lymphatic system is part of the vascular system and an important part of the immune system, comprising of a large network of lymphatic vessels and small bean-shaped organs called lymph nodes, that carry lymph throughout the body. Apart from its role in fighting infection and waste removal, it also maintains fluid balance and plays a role in absorbing fats and fat-soluble nutrients from the small intestine. During surgery for cancer, nearby lymph nodes are often removed. This disrupts the flow of lymph, which can lead to swelling, called lymphedema. Traditionally, following breast cancer surgery, practitioners have advised against repetitive upper-extremity activities and stressing the arm for fear that muscle strain could worsen lymphedema, that can affect the arm and trunk following breast cancer surgery and treatment. However, results from recent research have shown that strength training improves muscular fitness and functional ability without increasing the risk of developing lymphedema in the affected arm or exacerbating pre-existing lymphedema.
Strength training also plays an important role in prostate cancer survivors, in whom there is a treatment-associated reduction in muscle mass and muscle strength, which can compromise physical function, particularly in older men. Regular participation in strength training during the treatment period results in an improvement in muscular fitness. In survivors of head and neck cancer, strength training may be particularly important because of the associated shoulder dysfunction, which is a well-recognised complication of the neck surgery.
Even though research on the benefits of strength training during chemotherapy is limited, studies have shown that strength training led to a better chemotherapy completion rate (i.e. received their prescribed chemotherapy dose on schedule, instead of experiencing the delays commonly seen with chemotherapy) resulting in better clinical outcomes.
Management of fibromyalgia
Fibromyalgia is a chronic disorder that causes muscle pain and fatigue. It may also be associated with difficulty sleeping, memory problems and digestive disorders. It occurs most often in women. Its exact cause is not known and currently, there is no cure for fibromyalgia. However, exercise, including strength training, helps alleviate symptoms.
Health benefits of flexibility exercises (stretching exercises)
Flexibility is the ability to move muscles and joints through their full range of motion. Flexibility is developed by stretching. Stretching keeps the muscles flexible, strong, and healthy, which is needed to maintain a good range of motion in the joints. In the absence of regular stretching, muscles shorten and become tight. As a result, during activity muscles are weak and unable to extend all the way. This increases the risk of joint pain, strains, and muscle damage. Contrary to popular belief, stretching is not something which is performed only by sportspersons; everyone needs to stretch in order to protect their mobility and independence, and protect from joint and muscle injuries.
Health risks associated with physical activity and or exercise
Though the health benefits of exercise discussed above are well established, some risks associated with physical activity and exercise have also been documented.
Musculoskeletal injuries include injuries affecting the muscles, bones, joints and associated tissues such as tendons and ligaments. These are the most common complication associated with physical activity. Risk of musculoskeletal injuries is primarily related to the type and intensity of physical activity. For instance, walking is associated with very low risk of injuries compared to running and competitive sports are associated with higher injury rate compared to recreational sports/physical activities. Risk of injuries is also higher in contact sports such as wrestling, boxing, football etc compared to non-contact sports such as racquet sports, running, swimming etc. Preexisting conditions such as malalignments or lack of flexibility etc also increase the risk of injuries. Training errors such as rapid progression (too much too soon) of an exercise program, inadequate recovery, lack of proper warm-up and cool-down also increase the risk of injuries. Poor quality equipment (e.g. running shoes), training surface (e.g. uneven or banked surfaces), environmental mal-conditions (e.g. hot and humid weather) also predispose to a higher risk of injuries.
Rare, but much more tragic complication associated with physical activity and exercise is sudden death during or immediately after exercise, without any preceding trauma. Being counterintuitive and rare, these deaths grab instant media attention. The risk factors for CVDs include both modifiable and non-modifiable factors. Among the non-modifiable factors, family history, i.e. genetic factors play a predominant role. The paradox is that if a heart-related event is imminent in a person, its more likely to occur when that person is exercising than when he is not, as a result of various physiological alterations accompanying acute exercise.
The causes of sudden cardiac death vary with age. In young individuals, congenital (i.e. present from birth) and hereditary cardiovascular abnormalities, usually asymptomatic and often undiagnosed during life are the main causes. These include hypertrophic cardiomyopathy (HCM), congenital abnormalities of the coronary arteries and aortic stenosis. Some other, less common, causes include Marfan’s syndrome, mitral valve prolapse and myocarditis. To reduce the risk of sudden cardiac death in young individuals, the International Olympic Committee and the American Heart Association (AHA) have endorsed the practice of preparticipation cardiovascular screening.
In contrast, exercise-related sudden death in older individuals (greater than 35 years of age), and occasionally in younger individuals, is mostly due to coronary artery disease (coronary atherosclerosis); exercise-induced symptoms are often present. The risk for exercise-related cardiovascular events such as sudden cardiac death and acute myocardial infarction (AMI) is transiently increased during or shortly after a vigorous intensity exercise session, compared to rest, particularly in individuals with diagnosed or occult heart disease. The risk for these exercise-related cardiovascular events is disproportionately higher in habitually sedentary individuals when they perform the unaccustomed or infrequent exercise, compared to individuals who exercise regularly.
The risk for sudden cardiac death and AMI, in apparently healthy individuals, performing moderate-intensity physical activity is very low. When the exercise is performed regularly and exercise intensity is progressively increased, allowing enough time for adaptations to take place, the risk for exercise-related cardiovascular events in adults reduces further, even in individuals with pre-existing cardiovascular disease. Physical inactivity is a major and independent risk factor for coronary heart disease, on par with the three major risk factors – high serum cholesterol, smoking and high blood pressure. Like these three risk factors, physical inactivity is associated with about a twofold increased risk of developing coronary heart disease. It is also important to know that heart disease often gives warning signs; if you feel any chest pain during exercise, have difficulty breathing, or even feel more fatigued than usual, stop the exercise and seek medical assistance.
Regular physical activity delays the development of atherosclerosis and reduces the incidence of coronary heart disease. Thus the benefits of physical activity in those with or at risk for coronary heart disease appears to outweigh the risks. However, in contrast to adults, in young individuals, vigorous exercise does not improve the underlying congenital, hereditary cardiovascular abnormalities responsible for the exercise-related cardiovascular events. In these patients, the health risks of vigorous physical activity far exceed the benefits. However, as physical inactivity increases the risk for various lifestyle diseases including obesity and coronary artery disease, moderate-intensity physical activity is recommended in these individuals.
Exercise is medicine and has numerous health benefits. However, data suggests that vigorous physical activity transiently increases the risk of cardiovascular events among young individuals and adults with both occult and diagnosed heart disease, during or immediately after exercise. Even though this risk is very low in apparently healthy individuals performing the moderate-intensity exercise, being counterintuitive and rare, these deaths grab instant media attention. To allay the fears associated with such events, the American College of Sports Medicine and the American Heart Association, in their joint statement – ‘Exercise and Acute Cardiovascular Event: Placing the Risks into Perspective’, published in the journal ‘Medicine and Science in Sports and Exercise’ in the year 2007, stated – “Physicians should not overestimate the risks of exercise because the benefits of habitual physical activity substantially outweigh the risks.” Various studies have shown that maintaining physical fitness via regular physical activity is one of the most important defences against exercise-related cardiovascular events in adults.
The ability of exercise to restore function to organs, muscles, joints and bones is not shared by drugs or surgery. To draw the attention of policy-makers, the public health community and civil society to these issues, WHO chose the World Health Day 2002 theme as – ‘Move for Health.’ Encouraged by the success of this, ‘Move for Health Day’, an annual global initiative to promote physical activity, sponsored by World Health Organisation, was started by the WHO Member States on 10th May 2003. I will like to end the post with two quotes:
“No matter how far you have gone on the wrong road, turn back.”
– Turkish Proverb
“If you do not repair your gutter, you will have your whole house to repair.”
– Old Spanish proverb