Exercise Prescription

Dan Burnett

Mark B. Stephens

INTRODUCTION

Over two-thirds (68%) of all Americans are either overweight or obese, a remarkable increase over the last 30 years (6). Physical inactivity and obesity are correlated with increases in coronary heart disease, diabetes, certain cancers, and all-cause mortality. Lack of physical activity is also associated with osteoporosis, falls, and mental health issues, including depression (12). Sufficient physical activity protects against these conditions.
Guidelines from the Department of Health and Human Services (DHHS) and the American College of Sports Medicine^® (ACSM) recommend a minimum of 150 minutes of moderate activity per week (2) or 75 minutes of vigorous activity per week to obtain substantial health benefits (14). The guidelines further advise that more extensive health benefits can be obtained with 300 minutes of moderate or 150 minutes of vigorous activity per week and explicitly recommend that adults also engage in muscle-strengthening activities on 2 or more days a week. The ACSM guidelines additionally further recommend flexibility exercises on 2 days per week to maintain joint range of motion, as well as neuromotor exercise training 2-3 days per week (exercises involving motor skills including balance, agility, and coordination) (2).
Estimates from 2010 found that only 43.5% of U.S. adults met the minimum recommendations from the DHHS for aerobic activity, 21.9% met the muscle-strengthening guidelines, and only 18.2% met both the muscle-strengthening and minimum aerobic recommendations (4).
From 1998 to 2008, improvements in these percentages improved minimally, ranging from 2.4% to 4.2% (4).
Physical activity is one of the critically important Objective Topic Areas for Healthy People 2020 (8), the national effort to define public health priorities and goals for the United States. Multidisciplinary targets include the DHHS guidelines for physical activity (14) and the ACSM Position Stand on the Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory, Musculoskeletal, and Neuromotor Fitness in Apparently Healthy Adults: Guidance for Prescribing Exercise (2).
Health care providers are poor at recognizing, addressing, and documenting the physical activity needs of patients. National data indicated that in 1995-1996 physicians provided exercise counseling for 18% of all visits by obese patients (13). A more recent study compared counseling trends across time and noted no improvement in counseling rates for exercise despite the highly documented increase in the prevalence of obesity from 1995 to 2004 (10).
Current 2002 U.S. Preventive Services Task Force (USPSTF) recommendations (17) state that there is insufficient evidence to recommend for or against routine physical activity counseling (“I” recommendation). In a recent December 2010 draft statement the USPSTF recommended not routinely providing primary care dietary or physical activity counseling for adults without preexisting cardiovascular disease or its risk factors because the average benefit of counseling for such patients is small (“C” recommendation) (16).
The USPSTF draft statement proposed that clinicians consider selectively providing or referring specific (higher risk) patients for more intensive counseling (16).
The ACSM Position Stand strongly endorses interventions to increase physical activity for prevention of weight gain, for weight loss, and for weight maintenance after weight loss (1). A 2011 ACSM comprehensive review describes evidence-based summaries of the quantities and qualities of exercise appropriate for exercise prescriptions (2).
The American Medical Association also recently published lifestyle medicine competencies that specifically call for primary care physicians to be able to assess lifestyle “vital signs” including physical activity and to be able to collaboratively develop appropriate prescriptions in response (9).
The new Exercise Is Medicine initiative (http://www.exerciseismedicine.org), involving multiple commercial, medical, and academic entities and coordinated by ACSM, encourages physicians to include physical activity and exercise specifically in their prescribing practices for the treatment and prevention of chronic disease (5). Guidelines for preexercise graded exercise testing are discussed in Chapter 20 (Electrodiagnostic Testing).