Chapter 2: The Health Benefits Of Physical Activity PDF

Chapter -2 The Health Benefits Of Physical Activity ❑ 2.1. Physical Activity And Hypokinetic Diseases/ Conditions Hypokinetic diseases are conditions related to inactivity or low levels of habitual activity. Physical inactivity has led to a rise in chronic diseases....

Chapter -2 The Health Benefits Of Physical Activity ❑ 2.1. Physical Activity And Hypokinetic Diseases/ Conditions Hypokinetic diseases are conditions related to inactivity or low levels of habitual activity. Physical inactivity has led to a rise in chronic diseases. Some experts believe that physical inactivity is the most important public health problem in the 21st century. Each year at least 1.9 million people die as a result of physical inactivity. ▪ Data from the Aerobics Center Longitudinal Study (2009) indicated that low cardiorespiratory fitness accounts for substantially more deaths (16%) compared to other risk factors (i.e., obesity 2–3%; smoking 8–10%; high cholesterol 2–4%; diabetes 2–4%; and hypertension 8–16%). ▪ Individuals who do not exercise regularly are at a greater risk for developing chronic diseases such as coronary heart disease (CHD), hypertension, hypercholesterolemia, cancer, obesity, and musculoskeletal disorders (see figure 1.1). ▪ For years, exercise scientists and health and fitness professionals have maintained that regular physical activity is the best defense against the development of many diseases, disorders, and illnesses. ▪ In 1995, Center for Disease Control (CDC) and the American College of Sports Medicine (ACSM) recommended that every adult should accumulate 30 min or more of moderate-intensity physical activity on most, preferably all, days of the week. Figure 1.1 Role of physical activity and exercise in disease prevention and rehabilitation. ▪ Since 1995, new scientific evidence has increased our understanding of the benefits of physical activity for improved health and quality of life. ▪ In light of these findings, the American Heart Association (AHA) and the ACSM updated physical activity recommendations for healthy adults and older adults. ▪ These recommendations address how much and what kind of physical activity are needed to promote health and reduce the risk of chronic disease in adults. ▪ The recommended amounts of physical activity are in addition to routine activities of daily living (ADLs) such as cooking, shopping, and walking around the home or from the parking lot. ▪ The intensity of exercise is expressed in metabolic equivalents (METs). A MET is the ratio of the person’s working (exercising) metabolic rate to the resting metabolic rate. One MET is defined as the energy cost of sitting quietly. ▪ For adults (18–65 yr) and older adults (>65 yr), the ACSM recommends a minimum of 30 min of moderate-intensity aerobic activity 5 days per week or 20 min of vigorous-intensity aerobic exercise 3 days per week. ▪ They also recommend moderate- to high-intensity (8- to 12-repetition maximum (RM) for adults and 10- to 15-RM for older adults) resistance training for a minimum of 2 non consecutive days per week. Balance and flexibility exercises are also suggested for older adults. ▪ For substantial health benefits, adults should engage in aerobic exercise at least 150 min per week at a moderate intensity or 75 min per week at a vigorous intensity. In addition, adults and older adults should do muscle-strengthening activities at least 2 days per week. ▪ Children should do at least 60 min of physical activity every day. Most of the 60 min per day should be either moderate or vigorous aerobic activity and should include vigorous aerobic activities at least 3 days per week. Part of the 60 min or more of daily physical activity should be muscle strengthening activities (at least 3 days a week) and bone-strengthening activities (at least 3 days a week). ▪The term exercise deficit disorder (EDD) has been used to identify children who do not attain at least 60 min of moderate- to vigorous-intensity physical activity on a daily basis. Children having EDD may be susceptible to pathological processes associated with a physically inactive lifestyle. ▪Improvements in health benefits depend on the volume (i.e., combination of frequency, intensity, and duration) of physical activity. This is known as the dose-response relationship. Because of the dose-response relationship between physical activity and health, the ACSM/CDC physical activity recommendation states that “persons who wish to improve their personal fitness, reduce their risk for chronic diseases and disabilities, or prevent unhealthy weight gain will likely benefit by exceeding the minimum recommended amount of physical activity”. ▪Physical activity lowers the risk of hypokinetic conditions including dying prematurely, coronary artery disease, stroke, type 2 diabetes, metabolic syndrome, high blood lipid profile, cancers (colon, breast, lung, and endometrial), and hip fractures. ▪It also reduces abdominal obesity and feeling of depression and anxiety. ▪Physical activity helps in weight loss, weight maintenance and prevention of weight gain, prevention of fails, and improved functional health, improved cognitive function, increased bone density, and improved quality of sleep. ▪The Exercise and Physical Activity Pyramid illustrates a balanced plan of physical activity and exercise to promote health and to improve physical fitness (see figure 1.2). ❑2.2. Physical Activity And Cardiovascular Diseases ▪According to World Health Organization (WHO, 2011) cardiovascular disease (CVD) caused 17.3 million deaths (30%) worldwide in 2008, and it is projected to cause more than 26 million deaths by 2030. ▪ More than 80% of those cardiovascular deaths occurred in low- and middle-income countries. ❑2.2.1 Coronary Heart Disease (CHD) ▪ Globally, coronary heart disease (CHD) accounts for more deaths than any other disease, with more than 7.6 million people dying from it in 2005 (WHO 2007). ▪ CHD is caused by a lack of blood supply to the heart muscle (myocardial ischemia) resulting from a progressive, degenerative disorder known as atherosclerosis. ▪ Atherosclerosis is an inflammatory process involving a buildup of low-density lipoprotein (LDL) cholesterol, scavenger cells (monocytes), necrotic debris, smooth muscle cells, and fibrous tissue. ▪ This is how plaques form in the intima, or inner lining of the medium- and large- sized arteries throughout the cardiovascular system. ▪ As more lipids and cells gather in the plaques, they bulge into the arterial lumen. In the heart, these bulging plaques restrict blood flow to the myocardium and may produce angina pectoris, which is a temporary sensation of tightening and heavy pressure in the chest and shoulder region. ▪ A myocardial infarction, or heart attack, can occur if a blood clot (thrombus) or ruptured plaque obstructs the coronary blood flow. In this case, blood flow through the coronary arteries is usually reduced by more than 80%. The portion of the myocardium supplied by the obstructed artery may die and eventually be replaced with scar tissue. ▪Coronary Heart Disease Risk Factors: Epidemiological research indicates that many factors are associated with the risk of CHD. The greater the number and severity of risk factors, the greater the probability of CHD. ❖The Risk Factors For CHD Are: Age, Family History, Hypercholesterolemia, Hypertension, Tobacco use, Diabetes Mellitus or Prediabetes, Overweight and Obesity, and Physical Inactivity. ❑Physical Activity and Coronary Heart ▪ Disease Approximately 6% of CHD deaths worldwide can be attributed to a lack of physical activity (WHO, 2010). ▪ Physically active people have lower incidences of myocardial infarction and mortality from CHD and tend to develop CHD at a later age compared to their sedentary counterparts. ▪ Individuals who exercise regularly reduce their relative risk of developing CHD by a factor of 1.5 to 2.4. ▪ physically active lifestyle may prevent 20% to 35% of cardiovascular diseases. ▪ Physical activity exerts its effect independently of smoking, hypertension, hypercholesterolemia, obesity, diabetes, and family history of CHD.  2.2.2 Hypertension ▪Hypertension, or high blood pressure, is a chronic, persistent elevation of blood pressure that is clinically defined as a systolic pressure ≥140 mmHg or a diastolic pressure ≥90 mmHg. ▪Individuals taking antihypertensive medicine also have this diagnosis. Prehypertension is a term used to describe individuals with a systolic pressure of 120 to 139 mmHg, a diastolic pressure of 80 to 89 mmHg, or both. A clear link exists between hypertension and cardiovascular disease. ▪WHO (2011) identified hypertension as the leading cardiovascular risk factor, attributing 13% of deaths worldwide to high blood pressure. ▪Hypertension is also the primary risk factor for all types of stroke. About 15% to 40% of the global adult population has hypertension. ▪Regular physical activity prevents hypertension and lowers blood pressure in younger and older adults who are normotensive, prehypertensive, or hypertensive. ▪Compared to normotensive individuals, training-induced changes in resting systolic and diastolic blood pressures (5–7 mmHg) are greater for hypertensive individuals who participate in endurance exercise. ▪However, even modest reductions in blood pressure (2–3 mmHg) by endurance or resistance exercise training decrease CHD risk by 5% to 9%, stroke risk by 8% to14%, and all-cause mortality by 4% in the general population (Pescatello et al. 2004). ▪In a position paper on exercise and hypertension (Pescatello et al. 2004), the ACSM endorsed the following exercise prescription to lower blood pressure in adults with hypertension (see “ACSM’s Exercise Prescription for Individuals With Hypertension” below).. Exercise Prescription for Individuals with Hypertension (ACSM, 2013) ❑ Mode: Primarily endurance activities supplemented by resistance exercises Intensity: Moderate-intensity endurance (40–60% VO2R)* and resistance training (60–80% 1-RM) Duration: 30–60 min or more of continuous or accumulated aerobic physical activity per day, and a minimum of one set (8–12 reps) of resistance training exercises for each major muscle group. Frequency: Most, preferably all, days of the week for aerobic exercise; 2 or 3 days/wk for resistance raining. *VO2R is the difference between the maximum and the resting rate of oxygen consumption.  2.2.3 Hypercholesterolemia and Dyslipidemia ▪ Hypercholesterolemia, is an elevation of total cholesterol (TC) in the blood, is associated with increased risk for CVD. ▪ Hypercholesterolemia is also referred to as hyperlipidemia, which is an increase in blood lipid levels; dyslipidemia refers to an abnormal blood lipid profile. ▪ Approximately 18% of strokes and 56% of heart attacks are caused by high blood cholesterol (WHO, 2002). ▪ Age, gender, family history, alcohol, smoking are risk factors for hypercholesterolemia and regular activity reduced the chance of getting hypercholesterolemia and hyslipidemia. ▪ LDLs, HDLs, and TC: Cholesterol is a waxy, fatlike substance found in all animal products (meats, dairy products, and eggs). ▪ The body can make cholesterol in the liver and absorb it from the diet. ▪ Cholesterol is essential to the body, and it is used to build cell membranes, to produce sex hormones, and to form bile acids necessary for fat digestion. ▪ Lipoproteins are an essential part of the complex transport system that exchanges lipids among the liver, intestine, and peripheral tissues. ▪ Lipoproteins are classified by the thickness of the protein shell that surrounds the cholesterol. ❖The four main classes of lipoproteins are:- 1).chylomicron, derived from the intestinal absorption of triglycerides (TG); 2).very low-density lipoprotein (VLDL), made in the liver for the transport of triglycerides; 3).low-density lipoprotein (LDL), a product of VLDL metabolism that serves as the primary transporter of cholesterol; 4).and high-density lipoprotein (HDL), involved in the reverse transport of cholesterol to the liver. ▪The molecules of LDL are larger than those of HDL and therefore precipitate in the plasma and are actively transported into the vascular walls. Excess LDL-cholesterol (LDL-C) stimulates the formation of plaque on the intima of the coronary arteries. ▪ Physical Activity and Lipid Profiles: ▪ Regular physical activity, especially habitual aerobic exercise, positively affects lipid metabolism and lipid profiles. 2.2.4 Diabetes Mellitus ▪ Diabetes is a global epidemic. ▪ More than 346 million people worldwide have the disease (WHO, 2011). ▪ Factors linked to this epidemic include urbanization, aging, physical inactivity, unhealthy diet, and obesity. ▪ At least 65% of people with diabetes mellitus die from some form of heart or blood vessel disease (AHA, 2008). ▪ Diabetes is a major contributor toward the development of CHD and stroke. ▪ Also, diabetes is among the leading causes of kidney failure; 10% to 20% of people with diabetes die of kidney failure (WHO, 2008). ▪ Type 1, formerly referred to as insulin-dependent diabetes mellitus (IDDM), usually occurs before age 30 but can develop at any age. ▪ Type 2, previously known as non-insulin-dependent diabetes mellitus (NIDDM), is more common; 90% of individuals diagnosed with diabetes mellitus worldwide have type 2 diabetes (WHO, 2011). ▪ Age, gender, family history, calorie intake, physical inactivity are risk factors for developing diabetes. ▪ Type 1, diabetes may be caused by autoimmune, genetic, or environmental factors, but the specific cause is unknown. Unfortunately, there is no known way to prevent type 1 diabetes (CDC, 2011). ▪ Healthy nutrition and increased physical activity, however, can reduce the risk of type 2 diabetes by as much as 67% in high-risk individuals (Sanz, Gautier, and Hanaire 2010). ▪ Nearly 90% of cases of type 2 diabetes worldwide may be related to obesity (Wagner and Brath 2012). ▪ The effect of exercise alone as an intervention for people with type 2 diabetes is not well researched. ▪ However, exercise (30–120 min, 3 days/wk for 8 wk) produced clinically significant improvements in HbA1c and reduced visceral and subcutaneous adipose tissue stores in people with type 2 diabetes. Additionally, no adverse effects or diabetic complications resulting from exercise were reported (Thomas et al. 2006). ▪ Research that associates physical activity with weight loss, fat loss, and glycemic control suggests that regular physical activity reduces one’s risk of developing type 2 diabetes. ▪ Both resistance and aerobic exercise alone or in combination improve HbA1c values in people with type 2 diabetes. The frequency of exercise is crucial for those with diabetes. ▪ If daily exercise is not possible, it should not be skipped 2 days in a row. Dear Students, for specific guidelines for prescribing exercise programs for people who have type 1 and type 2 diabetes please refer ACSM Guideline (2014). ❖2.2.5 Obesity and Overweight ▪ adult overweight and obesity are classified using the body mass index (BMI) (BMI = weight [kg] / height squared [m2]). ▪ Individuals with a BMI between 25 and 29.9 kg/m2 are classified as overweight; those with a BMI of 30 kg/m2 or more are classified as obese. ▪ While WHO (2012) acknowledges the utility of BMI as a simple index of obesity, they also caution that it cannot account for the relative fatness of different individuals having the same BMI. ▪ Actually, they define overweight and obesity as having abnormal or excessive fat accumulation that may impair health. ▪ Regardless, overweight and obesity ranks as the fifth leading risk factor for death worldwide (WHO, 2012). ▪ Globally, more than 1 in every 10 adults is obese (WHO, 2012). ▪ Originally overweight and obesity were considered to be problems of high-income countries; now, these conditions are on the rise in the low- and middle-income countries (WHO, 2012). ▪In developed countries, approximately 8 million children are overweight. Age, gender, family history, cholesterol intake, and physical inactivity are the major factors associated with increased risk of obesity. ▪Although obesity is strongly associated with CHD risk factors such as hypertension, glucose intolerance, and hyperlipidemia, the contribution of obesity to CHD appears to be independent of the influence of obesity on these risk factors. ▪Restricting caloric intake and increasing caloric expenditure through physical activity and exercise are effective ways of reducing body weight and fatness while normalizing blood pressure and blood lipid profiles.  2.2.6 Metabolic Syndrome ▪ Metabolic syndrome refers to a combination of CVD risk factors associated with hypertension, dyslipidemia, insulin resistance, and abdominal obesity. ▪ According to clinical criteria adopted by the National Cholesterol Education Program (2001), individuals with three or more CVD risk factors are classified as having metabolic syndrome. ▪ Age and BMI directly relate to metabolic syndrome (National Cholesterol Education Program 2001). ▪ The prevalence of this syndrome is higher (>40%) for older (>60 yr) adults than for younger (20–29 yr) adults (7%). Also, the prevalence of metabolic syndrome is much higher for obese (BMI > 30 kg/m2) individuals (~50%) than for normal weight (BMI ≤ 25 kg/m2) individuals (6.2%). ▪ Lifestyle must be modified in order to manage metabolic syndrome. The combination of healthy nutrition and increased physical activity is an effective way to increase HDL-C and to reduce blood pressure, body weight, triglycerides, and blood glucose levels.  Aging ▪A sedentary lifestyle and lack of physical activity reduce life expectancy by predisposing the individual to aging-related diseases and by influencing the aging process itself. ▪With aging, a progressive loss of physiological and metabolic functions occurs; however, biological aging may differ considerably among individuals due to variability in genetic and environmental factors that affect oxidative stress and inflammation. ▪Telomeres are repeated DNA sequences that determine the structure and function of chromosomes. ▪ With aging and diseases associated with increased oxidative stress (e.g., CHD, diabetes mellitus, osteoporosis, and heart failure), telomere length decreases. ▪Thus, regular exercise benefits in retarding the aging process and diminishing the risk of aging-related diseases.  2.3 Physical Activity And Postural Deformity What Is Posture? ▪ Posture is the position from which movement begins and ends. Having proper postural alignment enables the body to perform movements quicker with less joint and muscular strain. Why Good Posture Is Important ? ▪ The body is designed to work at the most economical level, thus saving energy for future use. ▪ We spend more energy maintaining misaligned posture, which can cause muscle and joint pain. ▪ We compromise our body’s integrity by not maintaining proper posture, resulting in decreased circulation; leading to varicose veins, muscle pain, joint pain, and many other conditions. ▪ Women in general tend to develop poor posture because of many factors. ▪ They often have more clerical and computer oriented jobs that require sitting in a chair, eyeing a computer screen for long periods of time. ▪ They also wear high-heeled shoes, which lead to an alteration and compensation of their posture. ▪ The development of breast tissue or the augmentation of breasts can lead to many postural changes. ▪ Women also have less musculature to maintain proper alignment, leading to rounded shoulders, forward head posture, hyper-extended knees, and increased thoracic and lumbar curves. ▪ Men can also develop all of these postural problems but at a different degree and rate depending on their situation. ▪ To improve your posture and reduce structural damage, you should adhere to a corrective postural exercise program. ▪ Exercises for correcting posture:- Prone Cobra ,Axial Extension Trainer ,Wall Leans ,Cervical Extension using a blood pressure cuff  2.3.1 Musculoskeletal Diseases and Disorders ▪ Diseases and disorders of the musculoskeletal system, such as osteoporosis, osteoarthritis, bone fractures, connective tissue tears, and low back syndrome, are also related to physical inactivity and a sedentary lifestyle. ▪ Osteoporosis is a disease characterized by the loss of bone mineral content and bone mineral density due to factors such as aging, amenorrhea, malnutrition, menopause, and physical inactivity. ▪ It is becoming a major health issue, with an osteoporotic fracture occurring every 3 seconds worldwide. ▪ Wrist fractures precede the most common osteoporotic fracture, vertebral fractures. However, hip fractures are the most shocking. ▪ Although osteoporotic fractures may occur in any bone, a hip fracture is recognized as a surrogate measure of the health care burden and expense due to osteoporosis, especially for men and women ≥50 yr. ▪ Osteopenia, or low bone mineral mass, is a precursor to osteoporosis. Adequate calcium intake, vitamin D intake, and regular physical activity help counteract age- related bone loss. ▪.ACSM suggests the following exercise prescription to help counteract bone loss due to aging and preserve bone health during adulthood Mode: Weight-bearing endurance activities (e.g., stair climbing, jogging), activities that involve jumping (e.g., basketball, plyometric), and resistance training Intensity: Moderate to high, in terms of bone-loading forces Frequency: 3–5 times per week for weight-bearing endurance activities; 2 or 3 times per week for resistance exercise Duration: 30–60 min/day of a combination of weight-bearing endurance activities, activities that involve jumping, and resistance training that targets all major muscle groups ▪ Low back pain afflicts millions of people each year. ▪ More than 80% of all low back problems are produced by muscular weakness or imbalance caused by a lack of physical activity. ▪ If the muscles are not strong enough to support the vertebral column in proper alignment, poor posture results and low back pain develops. ▪ Excessive weight, poor flexibility, and improper lifting habits also contribute to low back problems. ▪ While some risks of associated with low back pain are not modifiable, such as gender and age, lifestyle behavior such as smoking, physical inactivity, flexibility, and muscular strength and endurance can all be improved. ▪ The origin of low back problems is often functional rather than structural, in many cases, the problem can be corrected through an exercise program that develops strength and flexibility in the appropriate muscle groups. ▪ Also, people who remain physically active throughout life retain more bone, ligament, and tendon strength; therefore, they are less prone to bone fractures and connective tissue tears.  ❑UNIT SUMMARY ❖Major chronic diseases associated with a lack of physical activity are CVDs, diabetes, obesity, and musculoskeletal disorders. ❖Cardiovascular diseases are responsible for 30% of all deaths worldwide. ❖The positive risk factors for CHD are the following: age, family history, dyslipidemia, hypertension, tobacco use, prediabetes or glucose intolerance, obesity, and physical inactivity. ❖The prevalence of obesity is on the rise, especially in developed countries; two of every three adults and more than one of every three adolescents and children are overweight or obese. ❖BMI is used to identify and classify individuals as overweight or obese. Cutoff values for obesity, however, may vary depending on ethnicity. ❖Metabolic syndrome is a term used to describe individuals who have three or more cardiovascular disease risk factors. ❖Osteoporosis and low back syndrome are musculoskeletal disorders afflicting millions of people each year. ❖To benefit health and prevent disease, every adult should accumulate a minimum of 150 min/wk of moderate-intensity physical activity or 75 min/wk of vigorous-intensity physical activity. For additional health benefits, increase physical activity to 300 min/wk and 150 min/wk, respectively, for moderate- and vigorous-intensity exercise.