A 64-year-old heart failure patient with a reduced ejection fraction complains of having to stop and rest after walking two city blocks and has difficulty carrying groceries into his house. He does not complain of feeling shortness of breath at rest or peripheral edema, his medication regimen is optimized, and he reports that he is sedentary most of the day. As a result he is referred to a phase 2 cardiac rehabilitation program, where he performs a cardiopulmonary exercise test to assess his starting functional capacity and to measure his maximal heart rate in order to optimize his exercise prescription. After regularly attending 3 cardiac rehabilitation sessions per week for 12 weeks and walking on at least one additional day on his own for 30 minutes. His maximal oxygen consumption assessed by the cardiopulmonary exercise test increased from 16.4 mL/kg/min to 20.5 mL/kg/min. The patient also reports that he is now able to walk multiple blocks without fatigue and is able to perform activities of daily living without issue. He is encouraged by the results and reports that he will continue to walk 4-5 days per week for 30-45 minutes at his local community fitness center.
Prior to the late 1980s it was common practice to discourage heart failure (HF) patients from participating in exercise and/or physical exertion. There was a widespread belief that placing additional stress on an already weak and damaged heart would have deleterious effects and ultimately shorten the lifespan of the HF patient. However, countless investigations have subsequently demonstrated exercise to not only be a safe form of therapy, but to also minimize exacerbations of classic HF symptoms (ie, dyspnea and fatigue), thereby improving New York Heart Association (NYHA) functional class. There is also robust evidence suggesting reductions in overall mortality and hospitalizations in exercising HF patients compared to their nonexercising counterparts. Numerous mid- to small-sized studies, meta-analyses incorporating a number of those studies,1 and a large-scale randomized clinical trial (Heart Failure—A Controlled Trial Investigative Outcomes of exercise training; HF-ACTION) consistently suggest reductions in mortality ranging from 15% to 40%.
This chapter will (1) elucidate the acute and chronic responses to aerobic exercise, (2) summarize exercise and functional testing protocols, (3) interpret the exercise testing response, and (4) utilize information garnered from points 1 to 3 to formulate an exercise prescription. Additionally, this chapter will provide an introduction to cardiac rehabilitation practices and common special exercise considerations for HF patients.
ACUTE RESPONSES TO EXERCISE
Increased myocardial oxygen demand during exercise requires coordinated adjustments and balance between the cardiovascular (CV), pulmonary, and central nervous systems to provide appropriate oxygen delivery and carbon dioxide clearance (Figure 45-1). Congestive HF is characterized by decreased left ventricular (LV) function, and an inability to meet systemic oxygen demand with exertion. These patients are frequently burdened by comorbidities such ...