Course # 91723 • What Healthcare Professionals Should Know About Exercise


Study Points

  1. Discuss the current epidemic of obesity.
  2. Identify reasons why patients do not wish to exercise, including the need for information in the patients' native languages.
  3. Discuss the physiology of exercise.
  4. Identify the benefits of exercise.
  5. Define contraindications to exercise.
  6. Describe each type of exercise.
  7. Discuss the guidelines for devising an exercise program, including recommendations by national specialty societies and government agencies relating to exercise.
  8. Identify effective exercise regimens for patients with certain diseases, such as diabetes, osteoporosis, and HIV.

    1 . Approximately what percentage of the adult population is overweight, obese, or severely obese?
    A) 30%
    B) 4%
    C) 55%
    D) 79%

    EPIDEMIOLOGY OF OBESITY/OVERWEIGHT

    As noted, within the past few decades, the prevalence of overweight and obesity has increased dramatically. In 1980, the percentage of obese and severely obese adults was 15.1% and 1.3% of the total population, respectively; by 1994, these numbers increased to 23.3% and 3.1% [1]. In 2002, 31.1% of the adult population was obese and 5.2% were severely obese [1]. Data collected in 2015–2016 show that 38.8% are obese, 7.7% are severely obese, and an additional 32.1% of adults are overweight [1]. This means that roughly 7 out of 10 Americans 20 years of age and older are above a healthy weight and may be at an increased risk for disease and early death.

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    2 . All of the following statements regarding the epidemiology of obesity and overweight are true, EXCEPT:
    A) Women have higher rates of grade 3 obesity than men.
    B) Prevalence of overweight is greater in women than in men.
    C) Asian Americans have a lower rate of obesity than the general population.
    D) The prevalence of obesity in adolescents has more than tripled since 1970.

    EPIDEMIOLOGY OF OBESITY/OVERWEIGHT

    With race/ethnic origin not factored, the prevalence of overweight and grade 1 obesity is higher for men than for women, but grade 2 and grade 3 obesity are more common in women [1]. In the overall population, 38.8% of men and 36.8% of women are obese, and approximately 5.5% of men and 9.8% of women have class III obesity [1].

    When considered as a single race, the prevalence of obesity among individuals of African (47.6%) and Hispanic (44.8%) descent is greater than that reported for adults of European or Caucasian (37.4%) descent [1]. American Indian/Alaska Natives and Native Hawaiian/Pacific Islanders have an obesity prevalence of 39.1% and 51.7%, respectively [17]. Asian Americans are an exception, with a prevalence of 12.7%, much lower than in the general population. Although the rate of obesity is higher in many American racial/ethnic groups compared to non-Hispanic whites, white individuals make up the majority of cases (55.2 million out of 70.7 million total cases) [17].

    Of particular concern is the increase in the number of children who have high BMIs. Presently, 13.9% of children 2 to 5 years of age, 18.4% of children 6 to 11 years of age, and 20.6% of adolescents between 12 to 19 years of age are obese [13]. The prevalence of obesity in adolescents has more than tripled since 1970 [39]. This is especially troubling because overweight adolescents have a 70% chance of becoming overweight or obese adults; if their parents are overweight or obese, this chance increases to 80% [14].

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    3 . Reasons cited in this course for lack of exercise include
    A) fear of injury.
    B) limited concentration.
    C) excessive concern with proper technique.
    D) All of the above

    ADULT INACTIVITY

    Numerous reasons for failure to exercise exist, including lack of interest, competing demands for limited leisure time, fear of injury or pain, no access to facilities, and lack of knowledge of proper technique. Most of these reasons are misguided and, with proper education, can be resolved so that patients will be able to incorporate exercise into their daily lives.

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    4 . All of the following statements regarding muscle fibers are true, EXCEPT:
    A) Type 1 fibers have a high excitability.
    B) Type 1 fibers have a large cell diameter.
    C) Type 2 fibers are numerous in quantity.
    D) Type 2 fibers have a fast conduction velocity.

    EXERCISE PHYSIOLOGY

    There are two types of motor units in skeletal muscle, Type 1 and Type 2. Type 1 has a small cell diameter, with a high excitability and fast conduction velocity. It has an oxidative profile with moderate contraction velocity and low fatigability. There are few muscle fibers of this type. In contrast, Type 2 has a large cell diameter, with low excitability but a very fast conduction velocity. Type 2 fibers are numerous in quantity, with a glycolytic profile and high fatigability. The small motor units, with Type 1 (also known as "slow-twitch") fibers, are recruited first and are frequently active, while the large motor units, with Type 2 ("fast-twitch") fibers, are used infrequently, in forceful contractions. Maximal efforts, in which fast motor units are recruited, cannot be sustained because of the rapid depletion of glycogen.

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    5 . In developing muscle mass, the "size principle" refers to which of the following?
    A) Slow-twitch muscle fibers are recruited first.
    B) Fast-twitch fibers are recruited after the majority of slow-twitch fibers have been recruited.
    C) Fast-twitch fibers will only be recruited if slow-twitch fibers cannot generate enough force to perform the required action.
    D) All of the above

    EXERCISE PHYSIOLOGY

    When exercising, the "size principle" should be considered in developing muscle mass. This refers to the fact that slow-twitch muscle fibers are the first fibers recruited to do an activity, while fast-twitch fibers are recruited after the majority of slow-twitch fibers have been recruited. Therefore, if a small or moderate amount of force is needed to perform an activity, slow-twitch fibers will primarily be used. Fast-twitch fibers will only be recruited if the slow-twitch fibers cannot generate enough force to fully perform the exercise. In order to make continued progress, both slow-twitch and fast-twitch fibers must be recruited. If a muscle fiber is not recruited, it will make no adaptation, such as an increase in size. In general, these two types of fibers are not different in the amount of force they produce, but rather differ in rate of force production. The "overload principle" refers to the idea that one must increase the resistance, frequency, or duration of an activity beyond that which would normally be expected. Overload will result in strength development.

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    6 . VO2 max refers to the
    A) maximum volume of oxygen consumed by the body during each hour of exercise.
    B) minimum volume of oxygen consumed by the body during each minute of exercise.
    C) maximum volume of oxygen consumed by the body during each minute of exercise.
    D) minimum volume of oxygen consumed by the body during each hour of exercise.

    EXERCISE PHYSIOLOGY

    VO2 max is the maximum volume of oxygen consumed by the body each minute during exercise. Oxygen consumption is equal to cardiac output multiplied by arterial-venous oxygen difference. It often is used as a measure of a person's maximal capacity to do aerobic exercise because oxygen consumption is linearly related to expenditure of energy. In general, exercise increases heart rate, which will then increase oxygen consumption. A rough correlation shows 65% of maximal heart rate correlates to 50% VO2 max.

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    7 . Exercise has been shown to
    A) reduce hemoglobin A1C.
    B) improve glycemic control.
    C) reduce baroreflex sensitivity.
    D) All of the above

    BENEFITS OF EXERCISE

    There is little doubt that exercise improves glycemic control in patients with diabetes and those with impaired glucose tolerance (i.e., persons who are at risk for diabetes). Exercise has been shown to reduce baroreflex sensitivity and heart rate variability in patients with type 2 diabetes [31]. It has also been shown to reduce glycated hemoglobin (A1C) approximately 1% [32]. A Cochrane Review concluded that exercise significantly improves glycemic control, lowers plasma triglycerides, and reduces visceral adipose tissue in people with type 2 diabetes. These improvements appear to occur independently of weight loss [33]. In addition, because nearly 75% of the risk of type 2 diabetes is attributable to overweight/obesity, the reduction in body weight and body fat through exercise also improves glycemic control and reduces the complications of diabetes.

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    8 . A significant association does not exist between excess body weight and which of the following types of cancer?
    A) Brain
    B) Colon
    C) Breast
    D) Cervical

    BENEFITS OF EXERCISE

    Various studies suggest a possible link between excess body weight and cancer, including colon, breast, endometrial, and possibly other cancers. Possibly the largest study to date was a 16-year prospective study that enrolled nearly one million participants (405,000 men and 495,000 women) from the Cancer Prevention Study II. The results showed that there were positive linear trends in death with increasing BMI values for esophageal, stomach, colon, rectal, liver, gallbladder, pancreas, prostate, cervical, ovarian, and kidney cancers, as well as non-Hodgkin lymphoma, multiple myeloma, and leukemia; there was no significant association with melanoma or cancers of the brain or bladder [37]. Other studies have indicated a slightly increased risk of melanoma and non-melanoma skin cancers [76]. A 2018 study estimated that cancers attributable to excess weight ranged from 3.9% to 6% in men and 7.1% to 11.4% among women [72]. It is suspected that most, if not all, cancers, while perhaps not directly caused by obesity, can be linked to lifestyles associated with obesity, including a diet high in fat and sugar and a marked lack of exercise.

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    9 . Which of the following is a contraindication to beginning an exercise program?
    A) Stable angina
    B) Type 2 diabetes
    C) Decompensated congestive heart failure
    D) Myocardial infarction in previous five years

    ASSESSMENT PRIOR TO EXERCISE

    CONTRAINDICATIONS TO BEGINNING AN EXERCISE PROGRAM

    Recent myocardial infarction (two weeks)
    Unstable angina
    Severe aortic stenosis
    Decompensated congestive heart failure (low ejection fraction)
    Left ventricular outflow obstruction
    Uncontrolled dysrhythmias
    Uncontrolled diabetes or diabetic complications
    Uncontrolled hypertension
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    10 . Muscular strength relates to
    A) sustaining repeated contractions for an extended period of time.
    B) applying force against a fixed object for an extended period of time.
    C) exerting maximum force for a brief period of time with repeated contractions until the muscle becomes fatigued.
    D) None of the above

    TYPES OF EXERCISE

    Anaerobic activities focus on muscular strength and muscular endurance. These activities, which involve major muscle groups, are typically known as "resistance training." Muscular strength relates to exerting maximum force for a brief time period with repeated contractions until the muscle becomes fatigued. Weightlifting is a good example. Muscular endurance involves sustaining repeated contractions or applying force against a fixed object for an extended period of time. Push-ups are an example of a muscular endurance exercise. Oxygen is not used, and the muscles produce lactic acid as a by-product.

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    11 . With respect to breathing during resistance training, all of the following are true, EXCEPT:
    A) Patients should exhale during the push phase.
    B) Patients should inhale during the resistance phase.
    C) The concentric phase is the push part of the exercise.
    D) Muscles gain strength from the concentric part of the exercise.

    TYPES OF EXERCISE

    Before beginning resistance training, patients should become familiar with two important concepts: correct form and breathing technique. Form is broken down into repetition rhythm, range of motion (ROM), and proper angle. The rhythm should be controlled and consistent, throughout the entire set of repetitions. One should resist the temptation to jerk the weight up or use momentum to move the weight. ROM simply means to fully extend or flex the muscle being worked. One should allow the muscle targeted to fully stretch at the bottom of the movement. Each exercise has two phases: the eccentric and concentric motion. The concentric is the pushing part of the motion and the eccentric is the resistance portion. Contrary to popular opinion, muscles get stronger from the eccentric part of the movement, or the stretch, not the push. Therefore, patients must go through the full range of motion to benefit. Each motion should be fluid, with equal time (e.g., three seconds up, three seconds down) given to the eccentric and concentric motions.

    With respect to breathing, patients should exhale during the push phase of each exercise and inhale during the resistance phase. For example, during a bench press exercise, one would inhale while lowering the weight to one's chest and exhale as one pushes it back up. Doing this allows the best possible flow of oxygen-rich blood to the working muscles. Patients should be cautioned not to hold their breath during any exercise because Valsalva maneuver, which increases intra-abdominal pressure, may occur. This happens when patients close the glottis and activate abdominal muscles. This increase in abdominal pressure causes an increase in blood pressure and should be avoided. One trick to encourage patients to breathe is to ask them to count the number of repetitions out loud.

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    12 . The current recommendation for physical activity by the Institute of Medicine is at least
    A) 30 minutes of exercise daily.
    B) 60 minutes of moderate-intensity exercise daily.
    C) 30 minutes of exercise at least 3 days of the week.
    D) 60 minutes of exercise at least 3 days of the week.

    DEVELOPMENT OF AN EXERCISE PROGRAM

    The current recommendation by the Institute of Medicine is for adults to set a long-term goal of at least 60 minutes per day of moderate-intensity physical activity (e.g., brisk walking) or shorter periods of more intense daily activity [42].

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    13 . Maximal heart rate is calculated as age subtracted from
    A) 120.
    B) 150.
    C) 200.
    D) 220.

    DEVELOPMENT OF AN EXERCISE PROGRAM

    The key criterion is for patients to elevate their heart rate. Patients should calculate their maximal heart rate as 220 - age. For example, a patient 45 years of age has a maximal heart rate of 175 bpm. For patients having difficulty finding their pulse, a pulse monitor, which is available at most gyms and health stores, can be used.

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    14 . Low intensity exercise is defined as exercising at
    A) <50% maximal heart rate.
    B) <60% maximal heart rate.
    C) >60% maximal heart rate.
    D) >70% maximal heart rate.

    DEVELOPMENT OF AN EXERCISE PROGRAM

    Low-intensity exercise is defined as exercising at <50% maximal heart rate; moderate-intensity is defined as exercising at 50% to 70% of maximal heart rate. Vigorous exercise generally involves a heart rate about 70% to 85% of a person's maximum [43].

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    15 . Approximately 50% of people who start an exercise program quit within
    A) one week.
    B) one month.
    C) three months.
    D) six months.

    EXERCISE MAINTENANCE, ADHERENCE, AND FAILURE

    It is estimated that approximately 50% of people who start an exercise program will have quit within six months. The people who are most successful demonstrate some of the following characteristics:

    • They have chosen a convenient, economical activity that is pleasurable.

    • They have set realistic goals, both short-term and long-term, that they track over time.

    • They structure exercise within their schedule.

    • They receive encouragement from family, friends, and healthcare providers.

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    16 . The American Heart Association (AHA) recommends
    A) providing an exercise prescription.
    B) asking patients specific questions about types of exercise activities.
    C) discussing implementation of physical activity at the workplace.
    D) All of the above

    SPECIALTY SOCIETY POSITION STATEMENTS

    The AHA strongly recommends physical activity counseling as an important strategy for implementing primary and secondary prevention guidelines. The AHA believes that healthcare providers should deliver counseling systematically, including asking specific questions about the kinds of activity and how much activity each patient is getting [47].

    The AHA specifically advises that in the patient-visit setting, physicians and their staff should discuss physical activity and provide exercise prescriptions for patients and their families. At times, implementing physical activity at the workplace should be discussed. The AHA recommends at least 30 minutes of moderate-intensity physical activity five days per week, or 25 minutes of vigorous exercise at least three days each week [81]. Moderate and vigorous activities can be combined to meet the goal, and moderate-intensity activities can be performed in 10-minute segments if necessary. They also recommend resistance training using free weights or gym equipment be done at least twice per week, with 8 to 10 exercises working different muscle groups repeated on non-consecutive days, starting with 10 to 15 repetitions and building to three sets of 15 repetitions for each body area [82]. For older adults, the AHA also advises stretching for flexibility, about 10 minutes at least twice per week [40,48].

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    17 . Which of the following specialty societies recommends considering an exercise test for patients at high risk of underlying cardiovascular disease?
    A) Institute of Medicine
    B) American Cancer Society
    C) American Medical Association
    D) American Diabetes Association

    SPECIALTY SOCIETY POSITION STATEMENTS

    The ADA has published guidelines for patients regarding exercise. The ADA recommends that patients with diabetes undergo a detailed medical exam prior to beginning an exercise program. Specifically, they recommend screening for macrovascular and microvascular diabetic complications that could be exacerbated by exercise. They also suggest considering an exercise test for patients at high risk of underlying cardiovascular disease. In general, however, the ADA recognizes that both type 1 and type 2 diabetics can and should participate in physical activity [51]. The ADA recommends at least 30 minutes of moderate-to-vigorous intensity activity at least five days every week for all adults, including adults with prediabetes or diabetes, and at least 60 minutes daily for children and teens [10]. It is important to not go more than two days in a row without exercise. Resistance exercise is recommended two to three days per week, aiming for three sets of 8 to 10 repetitions for each muscle group targeted. People with diabetes should check blood glucose before, after, and several hours following exercise, at least in the beginning of an exercise program.

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    18 . Regarding exercise in patients with diabetes, which of the following is TRUE?
    A) Most patients with diabetes can safely exercise.
    B) Patients with type 2 diabetes should not exercise.
    C) Patients with type 1 diabetes should not exercise.
    D) None of the above

    SPECIFIC DISEASE CONDITIONS

    Most patients with diabetes can safely exercise. Certainly, patients with uncontrolled diabetes should not begin an exercise program until glucose levels are stabilized. Patients with proliferative or severe nonproliferative retinopathy are advised to avoid vigorous exercise, because there is a potential risk of vitreous hemorrhage or retinal detachment. Patients with nephropathy or peripheral neuropathy have traditionally been told to avoid vigorous exercise. However, ADA recommendations state that both aerobic exercise and resistance training may actually be beneficial in patients with nephropathy. These patients do, however, need careful workup for cardiovascular risks, including a stress test. For patients with peripheral neuropathy, non-weight-bearing exercise is advised as a common-sense precaution, as limited sensation could increase the risk of injury. Autonomic neuropathy in diabetes is closely tied to cardiovascular disease and carries a risk of postural hypotension, impaired thermoregulation, and other serious problems; for these patients, a thorough cardiac investigation is recommended before starting an exercise program [51].

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    19 . Which of the following has been shown to increase bone mineral density?
    A) Stretching
    B) Aerobic activities
    C) Resistance training
    D) Taking vitamin E supplements

    SPECIFIC DISEASE CONDITIONS

    Although patients should include all types of exercises in a program, as discussed, it is important for them to perform resistance training to prevent and treat osteoporosis. This is because it is weight-bearing exercises—not aerobic or stretching—that increase bone mineral density (BMD). The increase in BMD subsequently reduces fracture risk. In order to increase BMD, there should be a physical stress on the muscles/bones. Brief, high-intensity periods of loading that generate a diversity of strain patterns on the bones provide an osteogenic response. Low-impact exercises do not create enough stress to increase muscle mass or BMD.

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    20 . For patients with HIV/AIDS, physical activity
    A) is contraindicated.
    B) may improve quality of life.
    C) may improve overall strength.
    D) Both B and C

    SPECIFIC DISEASE CONDITIONS

    HIV/AIDS is a significant public health problem. For many years, patients with HIV/AIDS were counseled not to engage in exercise. This was due to the belief that intense or prolonged exercise could lead to decreased immune function in a population that was already immunocompromised and/or immunodepressed. This belief has not been supported in the literature. Physical activity may in fact offer substantial health benefits for persons with HIV. Data suggest that exercise can improve HIV patients' quality of life and improve overall strength.

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