Special Considerations for Metabolic Syndrome, Hypertension, and Dyslipidemia
For additional ancillary materials related to this chapter, please visit thePoint.
Lifestyle therapy (i.e., beneficial modifications in diet and physical activity) is prescribed in the prevention and treatment of many cardiometabolic diseases, including high blood pressure (BP) (hypertension), abnormal blood lipids (dyslipidemia), or the clustering of cardiovascular and metabolic risk factors known as the metabolic syndrome. Exercise training may be just as effective, if not more, than certain pharmacological monotherapies for preventing mortality from cardiovascular disease (CVD) (22). This finding requires clinicians to understand the unique considerations for prescribing exercise training to ameliorate cardiovascular and metabolic risk factors. This chapter presents disease etiology and special considerations related to exercise testing, prescription, and progression for individuals with three cardiovascular or metabolic disorders: metabolic syndrome, hypertension, and dyslipidemia. The accompanying case study details a patient with hypertension and elevated low-density lipoprotein cholesterol (LDL-C) who wishes to increase his physical activity in order to alleviate side effects associated with several of the prescription medications he has been taking.
Mr. Case Study-BP
Mr. Case Study-BP is a 48-year-old male contractor who has recently been faced with some health concerns. He is self-employed and has only carried catastrophic health insurance for most of his adult life. When he became eligible to purchase insurance through a health insurance exchange in his state, he found a primary care physician and went for his first routine physical in over 20 years. At that time, Mr. Case Study-BP was diagnosed with stage 1 hypertension as his BP was 145/84 mm Hg. His doctor immediately prescribed a low-dose diuretic to bring his BP down. Mr. Case Study-BP was also diagnosed with an LDL-C of 185 mg ∙ dL−1 and, as a result, was started on 5 mg of a statin medication to be taken once daily. His doctor was very direct when she weighed Mr. Case Study-BP, stating that he was 9 kg (20 lb) overweight and was at risk for metabolic syndrome, diabetes, stroke, and heart disease. He was anxious and overwhelmed by the visit but felt thankful that his hypertension and elevated LDL-C were going to be treated immediately. Six months later, however, Mr. Case Study-BP has been frustrated by his inability to lose weight. Although his BP is now 136/82 mm Hg, he hates taking three daily medications (he also takes an over-the-counter baby aspirin at his physician’s recommendation) and is worried that he will need increasing amounts of medication to control his cardiovascular risk. The adult education catalog in his town advertises a 4-week health and wellness class for adults, so Mr. Case Study-BP signs up. The second class focuses on exercise with each participant receiving an individualized exercise prescription using an online program. His prescription is as follows:
Weeks 0–4: Exercise 20 minutes per day, three times per week, alternating 4 minutes walking with 1 minute running.
Weeks 5–8: Exercise 30 minutes per day, three to five times per week, alternating 2 minutes walking with 3 minutes running.
Weeks 9 onward: Run 30 minutes per day, 4–5 days per week.
He is also instructed not to perform heavy resistance exercise due to his hypertension; instead, he is instructed to do low-intensity body weight exercises such as push-ups and sit-ups twice a week.
 |
Metabolic syndrome is defined as the clustering of individual cardiovascular and metabolic risk factors that are related to obesity, insulin resistance, hypertension, and dyslipidemia. This clustering of abnormal risk increases an individual’s disease predisposition for both Type 2 diabetes and CVD. By definition, an individual is classified as having metabolic syndrome if he or she is diagnosed with any three of five risk factors: fasting plasma glucose ≥100 mg ∙ dL−1 (or being treated pharmacologically for elevated glucose), high-density lipoprotein cholesterol (HDL-C) <40 mg ∙ dL−1 in men or <50 mg ∙ dL−1 in women (or being treated for reduced HDL-C), triglycerides (TG) ≥150 mg ∙ dL−1 (or being treated for high TG), waist circumference >102 cm in men or >88 cm in women, and systolic blood pressure (SBP) ≥130 mm Hg or diastolic blood pressure (DBP) ≥85 mm Hg (or being treated for hypertension) (1). Recent statistics indicate that the prevalence of metabolic syndrome has dropped slightly overall in the United States from approximately 26% in 2000 to 23% in 2010 (21). However, disproportionately higher rates are observed in ethnic groups such as Hispanic/Latinos, American Indians, and Alaska natives such that prevalence rates in these groups may be almost twice as high as overall rates. The burden of metabolic syndrome is substantial because, in addition to the health risks associated with each individual cardiometabolic component, overall risk of CVD morbidity and mortality is two- to threefold higher in patients with metabolic syndrome (14).
Metabolic syndrome is considered largely a disease of unhealthy lifestyle practices, with many of the underlying risk factors for development of the syndrome involving poor diet and exercise, such as low levels of physical activity and fitness; high intake of soft drinks, diet soda, carbohydrates, meat, and fried foods; and unhealthy behaviors such as skipping breakfast and heavy alcohol consumption. Moreover, public awareness of the metabolic syndrome and its cardiovascular and metabolic risk is low. Consequently, treatment guidelines from the American Heart Association (AHA)/National Heart, Lung, and Blood Institute emphasize that the primary aim of treatment for metabolic syndrome is to treat the modifiable, underlying risk factors (obesity, physical inactivity, and atherogenic diet) through lifestyle changes (15). Guidelines include reducing body weight by 7%–10% over the first year of therapy with the goal to achieve a body mass index (BMI) <25 kg ∙ m−2; following a diet low in fat, trans fat, cholesterol, and simple sugars; and participating in 30 minutes per day of moderate-intensity exercise at least 5 days per week (but preferably achieving 60 min daily).
The primary goal of treatment in individuals with the metabolic syndrome is to reduce risk for clinical atherosclerotic disease, so treatment is designed to improve the major cardiovascular risk factors: elevated LDL-C, hypertension, and diabetes (blood glucose) (15). If absolute risk is sufficiently high to warrant drug therapy above and beyond lifestyle changes, then clinical guidelines for metabolic syndrome suggest following treatment guidelines for each individual risk factor. As pharmacological treatment for hypertension and dyslipidemia are discussed in the following sections, medications for treating elevated blood glucose alone will be presented in this section.
The American Diabetes Association (ADA) guidelines (3) suggest biguanides (metformin) as first-line therapy. These drugs reduce the amount of glucose released by the liver and moderately increase peripheral insulin sensitivity. Other classes of drugs include sulfonylureas and meglitinides (which stimulate the pancreas to release more insulin), thiazolidinediones (insulin sensitizers), and α-glucosidase inhibitors (which slow the absorption of carbohydrates into the bloodstream). Second-line polypharmacy often involves one or more of these drugs in addition to insulin supplementation. Of note is that, especially in patients who use insulin and/or insulin secretagogues (drugs that stimulate pancreatic release of insulin), acute exercise can evoke hypoglycemia (low blood sugar). Thus, the American College of Sports Medicine (ACSM)/ADA joint position statement on exercise and Type 2 diabetes recommends that individuals using these medications consider ingesting carbohydrates prior to and possibly after exercise and/or consider reducing oral medications or insulin dosing before and possibly after exercise (8). However, this recommendation is specific to the duration and intensity of exercise, the patient’s glucose level at the time of exercise, and the type and dose of medication(s) being used and should be interpreted on an individual clinical basis. Readers are encouraged to refer to a more comprehensive coverage of exercise prescription for individuals with Type 2 diabetes (see Chapter 14).
BP is defined as the force exerted by the blood against artery walls during the heart’s contraction and relaxation, with high BP or hypertension representing a pathological condition which contributes to CVD risk. A patient is classified as having hypertension if he or she has an SBP ≥140 mm Hg and/or DBP ≥90 mm Hg, or is taking antihypertensive medicine, or has been told at least twice by a physician or other health care provider that he or she has high BP (9). Even small elevations in BP over time increase the future risk of hypertension and cardiovascular events, and thus, the category of prehypertension is defined as untreated SBP of 120–139 mm Hg or untreated DBP of 80–89 mm Hg. Classification of BP categories according to the frequently used Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) (7) as well as the updated guidelines by the Eighth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 8) (16) are described in Table 15.1.
Quantitative Differences between JNC 7 and JNC 8 Guidelines |
JNC 7 Guidelines (SBP and DBP) | JNC 8 Guidelines (SBP and DBP) |
Blood pressure classification system Normal <120 and <80 mm Hg Prehypertension 120–139 or 80–89 mm Hg Stage 1 hypertension 140–159 or 90–99 mm Hg Stage 2 hypertension ≥160 or ≥100 mm Hg | Blood pressure goals <60 yr or with diabetes or CKD <140 and 90 mm Hg ≥60 yr <150 and 90 mm Hg |
CKD, chronic kidney disease.
From National High Blood Pressure Education Program. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Bethesda (MD): National Heart, Lung, and Blood Institute (US); 2004 Aug. Available from: https://www.ncbi.nlm.nih.gov/books/NBK9630/; and James PA, Oparil S, Carter BL, et al. 2014 Evidence-based guideline for the management of high blood pressure in adults: report from the panel members appointed to the Eighth Joint National Committee (JNC 8). JAMA. 2014;311(5):507–20.
Other important categories of BP classification routinely assessed by the National Health and Nutrition Examination Survey (NHANES) include being aware of one’s hypertension, being treated for hypertension, and having controlled hypertension (see Table 15.2 for specific definitions) (9). Hypertension is the most important CVD risk factor, accounting for 40% of all CVD deaths (23). Approximately one-third (32.6%) of U.S. adults ≥20 years of age have hypertension, and 17.2% of these individuals are unaware of their elevated BP (21). Even individuals who reach the age of 50 years with normal BP still have a 90% risk of developing hypertension within their lifetime (6).
Table 15.2 | Definitions of Hypertension According to the National Health and Nutrition Examination Survey |
Awareness: IF the patient with hypertension answers yes to the following question: “Have you ever been told by a doctor or health care provider that you had hypertension, also called high blood pressure?” THEN he or she is AWARE of his or her hypertension. |
Treatment: IF the patient with hypertension answers yes to the following questions: “Because of your high blood pressure/hypertension, have you ever been told to take prescribed medicine?” and “Are you now following this advice to take prescribed medicine?” THEN he or she is being TREATED for his or her hypertension. |
Control: IF the patient with hypertension has an SBP below 140 mm Hg and DBP below 90 mm Hg THEN he or she has CONTROLLED hypertension. |
From Crim MT, Yoon SS, Ortiz E, et al. National surveillance definitions for hypertension prevalence and control among adults. Circ Cardiovasc Qual Outcomes. 2012;5(3):343–51.
As the estimated medical cost for treatment of hypertension is $46.4 billion annually (21), the impact of hypertension on the U.S. health care system has made it a critical public health concern. Hypertension is a multifaceted disease with risk factors including age, race/ethnicity, family history of hypertension and genetic factors, lower education and socioeconomic status, greater weight, lower physical activity, tobacco use, psychosocial stressors, sleep apnea, and dietary factors (including dietary fats, higher sodium intake, lower potassium intake, and excessive alcohol intake) (21). Evidence suggests that despite the various mechanisms and etiologies underlying hypertension, modifiable factors such as diet and exercise comprise a large proportion of an individual’s overall risk for hypertension (25).
According to JNC 7 (7), patients with hypertension should be treated with medically supervised diet and lifestyle modifications first (i.e., reduced-sodium diets, increased physical activity, and recommendations for weight loss). Patients not at goal after these initial modifications should then be started on pharmacological therapy of one or more drugs depending on stage of hypertension (stage 1 or 2) and existent underlying disease such as chronic kidney disease or diabetes. In JNC 8 (16), these guidelines were revised to relax BP treatment goals by 10 mm Hg for older adults >60 years of age as well as patients with chronic kidney disease or diabetes. JNC 8 guidelines, however, were not wholly embraced by the medical community, many of whom continue to utilize JNC 7 treatment paradigms for patients. Qualitative differences between the guidelines are summarized in Table 15.3.
Table 15.3 | Major Qualitative Differences between JNC 7 and JNC 8 Guidelines |
JNC 7 Guidelines | JNC 8 Guidelines |
Standardized definitions
| No definitions for diagnosis
|
Treatment regimen depends on other diseases.
| Treatment regimen is more uniform independent of disease.
|
Comprehensive description of lifestyle therapy
| References guidelines for lifestyle therapy
|
Five classes of drugs
| Four classes of drugs
|
Comprehensive topic coverage
| Limited topic coverage
|
From Chobanian AV, Bakris GL, Black HR, et al. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report. JAMA. 2003;289(19):2560–72; and James PA, Oparil S, Carter BL, et al. 2014 Evidence-based guideline for the management of high blood pressure in adults: report from the panel members appointed to the Eighth Joint National Committee (JNC 8). JAMA. 2014;311(5):507–20.
There are many classes of antihypertensive medications that influence peripheral vascular resistance or cardiac output (or both). These include medications that target rate-limiting enzymes of the renin-angiotensin-aldosterone system, β-adrenergic receptors in the heart, vasodilation, or fluid balance, among others. JNC 8 recommends any drug from one of the four following classes to be a good choice as initial therapy: thiazide-type diuretics, calcium channel blockers, angiotensin-converting enzyme inhibitors, or angiotensin II receptor antagonists (16). Drug monotherapy typically results in a reduction in SBP or DBP of 5–10 mm Hg, but these reductions are dependent on factors such as the patient’s baseline BP and the mechanism underlying hypertension. In addition, combining doses of multiple classes of BP-lowering drugs is preferred because this treatment is more effective than doubling the dose of one BP drug (34). Multiple other factors contribute to the choice to utilize one or more antihypertensive drugs from the various classes (e.g., race, disease, age) (16), and thus pharmacological management of hypertension requires adjustment of doses and classes of medications over time.
Dyslipidemia is defined as abnormal levels of blood lipids. There are three atherogenic lipoproteins: very low density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), and LDL-C. LDL-C is the major atherogenic protein and lipid risk marker; a 10% increase in LDL-C leads to an approximate 20% increase in coronary heart disease (CHD) risk (35). TG are also associated with an increase in CHD events, although their link to CHD is complex and may be related to the other risk factors such as LDL-C and HDL-C subfractions, abdominal obesity, insulin resistance, and hypertension (13). HDL-C, by contrast, reduces the risk of atherosclerosis and CHD. The four major blood lipid measurements (total cholesterol [TC], with components of HDL-C, LDL-C, TG) and their ratios in relationship to each other are the primary targets used to diagnose and treat CVD risk.
Dyslipidemia is a major public health problem. Approximately 13% of U.S. adults have elevated TC (21), and 30% elevated LDL-C, the latter which doubles their heart disease risk (23). Because CVD (heart disease and stroke) accounts for about 1 of every 3 deaths in the United States, treating abnormal blood lipids is vital to reduce heart disease deaths in the United States.
Treatment guidelines based primarily on serum LDL-C levels were established by the National Cholesterol Education Program Adult Treatment Panel III (ATP III) in May 2001 (13). These guidelines suggest an LDL-C treatment goal, based on current and estimated cardiovascular risk and risk factors, ranging from 100 to 160 mg ∙ dL−1 for patients. Recently released 2013 guidelines (32) by the American College of Cardiology (ACC) and the AHA dramatically revised the treatment guidelines for hyperlipidemia, focusing on risk of stroke and coronary disease rather than strictly defined target LDL-C levels as a rationale to treat an individual. These ACC/AHA guidelines emphasized a benefit of pharmacological treatment for individuals with LDL-C >190 mg ∙ dL−1 and/or diabetes, established CVD, or high risk of CVD. For both sets of guidelines, lifestyle modification such as routine aerobic and resistance exercise and heart-healthy diet adherence are recommended as initial therapy and in addition to pharmacology. Quantitative and qualitative differences between the two guidelines are summarized in Table 15.4 and Table 15.5, respectively.
Quantitative Differences between ATP III and ACC/AHA Guidelines |
ATP III Guidelines | ACC/AHA Guidelines | ||||||||||
LDL goal
| LDL goal No recommendation | ||||||||||
Threshold of LDL of which to initiate drug therapy
| Threshold of LDL of which to initiate statin therapy
| ||||||||||
Classification of LDL (mg ∙ dL−1)
| Classification of LDL (mg ∙ dL−1) No recommendation | ||||||||||
Classification of HDL (mg ∙ dL−1)
| Classification of HDL (mg ∙ dL−1) No recommendation | ||||||||||
Classification of TC (mg ∙ dL−1)
| Classification of TC (mg ∙ dL−1) No recommendation |
ASCVD, atherosclerotic cardiovascular disease.
From Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Executive summary of the third report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). JAMA. 2001;285(19):2486–97; and Stone NJ, Robinson JG, Lichtenstein AH, et al. 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014;129(25 suppl 2):S1–45.
Related posts:
Special Considerations for Type 1 and Type 2 Diabetes Mellitus
The Health Consequences of Physical Inactivity and Sedentary Behavior
Special Considerations for Cardiovascular Disease: Chronic Stable Angina and Coronary Artery Bypass Graft Surgery
Special Considerations for Cardiovascular Disease: Valvular Heart Disease and Peripheral Artery Disease
Flexibility and Functional Movement Assessments
Special Considerations for Cardiovascular Diseases: Ventricular Assist Devices and Heart Transplantation
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
