Beyond ischemia evaluation: The potential for assessing and addressing physical inactivity in the cardiac stress laboratory

Abstract

Exercise has been shown to have beneficial effects in a wide range of disease states including cardiovascular disease, pulmonary disease, and cancer. Large prospective studies have illustrated the mortality benefit associated with exercise and physical activity, with even small amounts of exercise conferring mortality benefits. A recent study has shown that the benefit of exercise is at least that conferred by drug interventions. Furthermore, exercise has a favorable side effect profile compared to the most effective medical therapies. Despite these benefits, levels of occupational related physical activity and leisure time physical activity remain suboptimal in the US. The BRFSS reported that in 2010, 25% adults in the US do not engage in any leisure time activity. Furthermore, only 50% of US adults meet the recommended amount of leisure time activity. In regards to occupational related physical activity, Church et al found that the number of jobs requiring moderate physical activity decreased from 48% to 20% between 1960-2008, along with a concomitant increase in jobs that require light physical activity or are categorized as sedentary jobs. There was also a decrease in time spent on household management between 1965-2010 resulting in a decrease in energy expenditure during household duties. Taken together, the US has become a more sedentary society in which the requirements for occupational energy expenditure has decreased and the levels of leisure time activity have not increased enough to offset this trend. In an era of increasing healthcare costs, physical inactivity is thought to be responsible for 12.2% of the global burden of myocardial infarction and to account for between 1.5% and 3.0% of total healthcare expenditures in the US. Thus, the challenge remains in how to efficiently identify, assess, and motivate patients to increase their physical activity. An important step would be to identify a point of contact with patients where physical fitness could be assessed and addressed with proven methods of intervention. In the current issue of the Journal of Nuclear Cardiology , Poulin et al evaluate the prognostic value of patients ability to perform exercise during stress testing. This study included 1,511 patients who were prospectively enrolled at a single center. Patients were divided according to stress modality into three groups: (1) exercise by the Bruce protocol, (2) low level exercise plus adenosine, and (3) and adenosine only. More than three quarters of patients enrolled in this study underwent exercise testing, with 10% and 13% of the patients undergoing adenosine plus exercise and adenosine only protocols, respectively. In the overall cohort, 89% of single-photon emission computed tomography (SPECT) images were normal. The authors used the social security death index (SSDI) to ascertain patients’ status as alive or dead. In patients who were deceased, the cause of death was ascertained using their death certificates. Causes of death were categorized as cardiac, non-cardiac, or unsure. Poulin et al report a gradient of risk associated with the inability to exercise, with the highest event rates (allcause mortality and cardiovascular events) associated with patients undergoing an adenosine only protocol, an intermediate event rate associated with the adenosine plus exercise protocol, and the lowest event rate associated with those patients able to perform the Bruce protocol. In addition, the current study found a higher Reprint requests: Seth Uretsky, MD, FACC, Department of Cardiovascular Medicine, Gagnon Cardiovascular Institute, Morristown Medical Center, 100 Madison Ave, Morristown, NJ 07960; seth.uretsky@atlantichealth.org J Nucl Cardiol 2016;23:212–4. 1071-3581/$34.00 Copyright 2015 American Society of Nuclear Cardiology.