Exercise or health/fitness facilities welcome new members because membership is critical to the financial health of these programs. Thus, when a prospective member tours a facility, considerable effort is often expended, ensuring that the facility makes a very positive impression. The goal is to convince prospective members that the facility is a good match for them, and they should join it. Unfortunately, what may be overlooked during the recruitment process is that the employees also should be determining whether the prospective member is a good match for thefacility. In other words, although the prospective member is assessing the appropriateness of the facility, the facility also should be assessing the appropriateness of the potential member. Part of this process is known as risk classification, which is an attempt to make sure that this particular person can exercise safely within this particular facility.
An important aspect of risk classification includes determining whether exercise increases the risk of having an adverse event. The term “adverse event” can include varied complications such as orthopedic or musculoskeletal injuries. Although these types of injuries are too common, the most worrisome adverse events are cardiac related, such as a myocardial infarction (heart attack) or other complication leading to sudden cardiac death (9,10). In people younger than 35 or 40 years, these cardiac-related complications are often caused by congenital or hereditary conditions; in other words, the person has had this pathology, such as an abnormally enlarged heart, his or her entire life (9,10). In middle-aged and older adults, a cardiac-related complication is typically caused by atherosclerosis affecting blood flow to the heart. For example, it has been estimated that more than 80% of exercise-related sudden cardiac deaths in people aged 40 years or more are caused by atherosclerotic cardiovascular disease (CVD) (10). Fortunately, adverse cardiovascular events during physical activity are rare and estimated to be less than 0.01 per 10,000 hours (10). They are even less common in people who are regular exercisers and, especially, if their exercise is relatively vigorous. On the other hand, an acute bout of vigorous exercise in sedentary people markedly increases the relative risk of an acute cardiovascular event (1). Thus, although the risk of serious adverse cardiovascular events with exercise is statistically quite low, the risk is increased in beginning exercisers and, especially, those with underlying CVD (9). In this context, recent studies of health/fitness facilities found that 17% to 27% of the facilities surveyed had experienced a serious cardiac-related emergency within the previous 2 years (11,16). It is not surprising then that determining how best to minimize this risk should be a very real concern in all health/fitness facilities. Risk classification, with its strong focus on determining the likelihood of whether a participant has known or latent underlying CVD, can be an important and easy-to-use tool to use to keep the risk of cardiac-related adverse events as low as possible.
For example, consider a 55-year-old businessman who, after being sedentary for 20 years, decides to start exercising again. His younger sister had a heart attack recently, and it made him decide he needed to improve his own personal health. He is now looking for a local venue within which to begin exercising. Which of the following facilities is most appropriate for him: the one oriented to improving sport performance in athletes; the weightlifting gym oriented to body builders; the unsupervised facility at a local hotel; the community parks and recreation facility; the nearby racquet and fitness center; the wellness facility administered by his employer; or should he just walk around his neighborhood?
Now consider a slightly different scenario: suppose that, instead of his sister having had the heart attack, the businessman had it. He just finished 6 weeks of cardiac rehabilitation without difficulty and is now looking for a place to continue exercising. Which of these facilities would be a good choice for him now?
Did this change in his life situation alter your decision as to where he should exercise? What factors did you consider in making your decision? If you considered his CVD risk factorsin the first scenario (among other things) but his personal medical history in the second scenario and then thought about which type of exercise facility could best work with this potentialclient, then you began the process of risk classification.
Risk classification is an important aspect of assessing any potential client. Consequently, both it and preparticipation health screening are reviewed at length in the American College of Sports Medicine’s Guidelines for Exercise Testing and Prescription (2) and the companion Resource Manual (3). Because a client’s risk for atherosclerotic CVD is likely a major concern, the present article will focus on issues associated with CVD risk factor assessment within the context of risk classification in a typical fitness center.
AN OVERVIEW OF RISK CLASSIFICATION
The goal of risk classification is to determine whether potential clients can exercise safely. Not surprisingly, an important step is to gain some insight into their likelihood of having an adverse event while exercising because of an underlying disease. The American College of Sports Medicine has developed three categories of risk for the presence of CVD: low, moderate, and high (2). A potential client is placed into one of these categories based on answers to the following three questions:
- Has the person been diagnosed with a cardiovascular, pulmonary, or metabolic disease?
- Does the person have any signs or symptoms suggestive of these diseases?
- Does the person have an increased risk for CVD because of the presence of two or more CVD risk factors (Table 1)?
If the answer is “no” to all three questions, then the participant is considered low risk because the probability that he or she actually has clinically significant CVD is low. If the answer is “no” to the first two questions but “yes” to the third question, then the person is at moderate risk because the probability of having CVD has increased. If the answer is “yes” to either of the first two criteria, then the person is considered high risk because the probability of actually having CVD has increased even more. Because of the increased likelihood of having underlying disease, someone in the moderate-risk category should be encouraged to consult with his or her personal physician. Nevertheless, because the risk of an exercise-related cardiac event is associated primarily with vigorous-intensity exercise, it is acceptable for someone in the moderate-risk category to begin a program of light- to moderate-intensity exercise, such as walking, without consulting a physician. Those in the high-risk category should be required to consult with a physician, and possibly undergo exercise testing, before initiating a program of exercise, regardless of intensity.
Determining these answers is not that difficult; it also is not commonly done in most health/fitness centers (11,16). This is unfortunate because risk classifying potential participants would likely reduce the incidence of serious adverse cardiac events in these facilities simply by the early identification of individuals at an increased risk.
Consider our two businessmen scenarios. When he tells you that he was recently discharged from a cardiac rehabilitation program, you can instantly place him into the high-risk category because he clearly has been diagnosed with CVD. The other scenario, where the sedentary businessman is prompted to begin exercising again because of his sister’s heart attack, is a bit more challenging. Even with the very limited information we have, we can confidently place him in the moderate-risk category because he has more than two CVD risk factors (i.e., age, physical inactivity, family history). However, we do not have enough information to decide if he should be in the high-risk category; for example, does he have any signs or symptoms suggesting that he already has CVD? We need more information to make the most informed decision.
Getting this information is straightforward: have the person complete a health/medical history questionnaire and determine specific CVD risk factors. The Physical Activity Readiness Questionnaire has long been used as a self-guided tool for the health/medical history screening. It recently has been improved (20), renamed the PAR-Q+, and a user-friendly online version is available at www.eparmedx.com. At a fitness center, where competent professional staff are available to review the questionnaire responses, a reasonable alternative is the AHA/ACSM Health/Fitness Facility Preparticipation Screening Questionnaire (2,4). Both questionnaires probe for the presence of signs or symptoms of CVD as well as other health issues. In the context of CVD, the advantage of the latter questionnaire over the PAR-Q+ is that it explores more completely the presence of CVD risk factors. A disadvantage is that it does not fully assess all the clinically relevant risk factors. Of course, a fitness center can develop its own medical/health history questionnaire using the guidelines described in Box 3.1 of the ACSM guidelines (2).
CVD RISK FACTOR ASSESSMENT
Regardless of the questionnaire used, fitness center staff alsomust determine the presence of any of the established CVD risk factors (positive and negative). These CVD risk factorsare described in Table 1 (2). Identifying whether someone does or does not have a particular risk factor is not difficult; simply compare the participant’s information with that in Table 1. For risk classification, total the number of risk factors. Note that a high-density lipoprotein (HDL) value more than 60 mg/dL is a negative risk factor because it assumes reduced CVD risk; therefore, if present, it would be subtracted from the total number of risk factors. If information about a specific risk factor is not known, assume that the participant has that risk factor. Finally, blend this information into that gained from the health/medical history questionnaire to determine if the client should be placed in the low-risk, moderate-risk, or high-risk categories.
Nevertheless, when attempting to identify a potential client’s overall risk for CVD (and, by extension, risk for an adverse cardiovascular event) based on his or her CVD risk factors, there are a host of caveats that need to be considered. In other words, fully assessing a client’s risk for CVD is more complex than simply comparing risk factors with a list and using a yes-no format. First, the presence of a risk factor is defined by a given threshold such as those depicted in Table 1. The significance of risk is partly dependent on the magnitude, or severity, of the risk factor. Consider that all cigarette smokers have smoking as a risk factor, regardless of how many cigarettes are smoked. Thus, both the person who smokes just a cigarette each day and a two-pack per day smoker has this CVD risk factor. However, there is a very strong dose-response relationship between atherosclerotic CVD and tobacco use, such that heavy smokers have an increased risk compared with occasional smokers. In one large study, it was estimated that every cigarette smoked increased one’s risk for an acute heart attack by approximately 6% (18). Therefore, classifying someone as a smoker without due consideration of smoking habits (e.g., average number of cigarettes per day) may lead to an underappreciation of the magnitude of his or her risk. In the case of cigarette smokers, a two-pack per day smoker has a risk for CVD that’s almost nine times that of someone who smokes just one cigarette daily (18). In summary, even if a potential participant only possessed one risk factor, they may have a substantial risk for CVD if this risk factor was severe enough.
The notion of a “risk factor continuum” also extends to borderline risk factors or a risk factor that is below the criterion threshold but above the desired level. Consider hypertension — one definition of hypertension is a resting systolic blood pressure of 140 mmHg or higher (2). This number is the threshold because it is associated with about a twofold higher risk for CVD compared with someone with the desired systolic blood pressure of less than 120 mmHg (7). Nevertheless, someone with a systolic blood pressure between 120 and 140 mmHg has about a 20% to 40% increased risk for CVD (15). However, this person would not be defined as hypertensive perse and, like the heavy smoker, the magnitude of his or her risk may be underestimated. In one large-scale study, people with only borderline risk factors had a risk for CVD that was twice that of people without increased risk factors (12). Because of this increased risk, individuals with an increased blood pressure, as described here, are now considered prehypertensive in the same way that someone with an increased fasting blood glucose level (i.e., >100 mg/dL) is prediabetic. The take-home message here is that, when assessing a potential participant’s risk for CVD, borderline risk factors can contribute to CVD risk in a substantial way.
A second issue to be considered when assessing the CVD riskassociated with risk factors is that they interact. For example,both increased age and diabetes are independent risk factors for CVD. However, when determining CVD risk severity, one study found that being diabetic was equivalent to aging 15 years (6). The magnitude of this interaction varies by the combination of the relevant risk factors but, in general, this influence is not simply additive. Thus, the clinical importance of a client having two risk factors, as opposed to having none or one, is partly dependent on which two risk factors the client has and, as described earlier, the severity of these risk factors.
A third consideration is that risk factors are not immutable. Their identification, as well as our understanding of their relative importance, continues to evolve. Consider physical inactivity and obesity. They are both epidemic in the United States and comprise substantial risk factors for CVD. It is not surprising then that many potential fitness center members want to improve both. Nevertheless, recent studies suggest that increases in physical activity may be more important than relatively similar improvements in adiposity for reducing CVD mortality (14). Thus, fitness may be more important than fatness in affecting CVD risk. In addition, new, or novel, risk factors are frequently being identified, but it takes time for their practical utility to be verified. For example, elevations in C-reactive protein are associated with an increased prevalence of CVD (17), but its usefulness as an independent risk factor remains debatable (19). Consequently, routine screening for increased C-reactive protein is not currently recommended, but this may change as we learn more. The criteria for established risk factors also change as more knowledge of their association with CVD is gained. Hyperlipidemia, for example, is very well established as a risk factor for CVD (2). However, the threshold for an abnormal elevation in serum total cholesterol 50 years ago was 260 mg/dL (13), whereas 200 mg/dL is the threshold now. Moreover, we now know that total cholesterol measurements are essentially a surrogate measure for the more clinically meaningful low-density lipoprotein cholesterol (LDL-C). Thus, LDL-C should be assessed in preference to total cholesterol when available (2). The notion of an evolving definition of a risk factor also applies to physical activity. Earlyguidelines for exercise were regimented in terms of frequency, intensity, duration, and type of activity because the focus primarily was on increasing maximal oxygen consumption; over time, they have become less structured in recognition that regular physical activity can have a positive health impact (5). The point to recognize is that risk factor criteria are dynamic entities and fitness professionals need to remain current in their knowledge and understanding of all the risk factors and permutations of the risk factors.
Given the complexity of CVD risk factors and how they influence CVD risk, what is the best approach to use when identifying a client’s risk for CVD? A simple effective method to use may be a risk score where a client’s risk for developing CVD is estimated based on the interactive effects of several riskfactors. A number of risk scores are available, each usingdifferent combinations of CVD risk factors to predict CVD-related outcomes (Table 2). Perhaps the most widely usedrisk scores in the United States are those developed fromthe ongoing Framingham Heart Study (www.framinghamheartstudy.org), which began in 1948 and includes risk factor assessments of multiple generations of families. Several Framingham risk scoring algorithms are available, yet the one recommended here can be used to estimate a client’s 10-year risk for having a CVD event (8). Risk is calculated based on the client’s sex, age, total cholesterol, HDL cholesterol (HDL-C), systolic blood pressure (and if treated for hypertension), tobacco use, and diabetes status. If lipid measurements are not available, a slightly less accurate 10-year risk estimate can be made using body mass index. Pen-and-paper versions are available but, in a fitnesscenter environment, a more practical method is to use either the interactive Microsoft Excel spreadsheet version or theonline interactive tool (both available at www.framinghamheartstudy.org/risk/gencardio.html). Both versions will estimate a client’s 10-year risk for CVD, what is normal for someone of his or her age and sex, and what is considered ideal. For example, the Figure is a screenshot of the output from the online interactive Framingham algorithm for a 46-year-old man with prehypertension, mildly reduced HDL-C, and acceptable total cholesterol. For many people, these risk factors may not be worrisome enough to warrant the time and effort of changing them. However, the risk score indicates that this client’s 10-year risk for CVD is an eye-opening 1.7 times higher than normal for men his age and 3 times higher than what it could be. Knowing this may be enough to prompt someone to begin a lifestyle modification program, perhaps complemented by cardioprotective medications, to improve these risk factors.
Moreover, risk scoring algorithms allow you to do “what-if” scenarios. What if this client made modest improvements in his blood pressure and lipids? As can be seen in the Figure, relatively small changes would cut his risk almost in half and normalize his 10-year risk. Knowing this information may, in turn, further increase his desire to change other risk factors. Given how simple they are to use and their sophisticated approach, a risk scoring algorithm can be a powerful ally when assessing a client’s risk for CVD. Because CVD is a major concern when performing risk classification, CVD risk scoring can be a valuable tool for health/fitness facilities.
In summary, risk classification and CVD risk assessment should be routinely performed in any exercise-promoting facility. Both can be done relatively quickly and with little to no expense on the part of the facility. However, the information they can provide is immensely useful both to the facility and to the participant.
CONDENSED VERSION AND BOTTOM LINE
Risk classification is a critically important step to take when working with new clients. Risk classification, especially when done in concert with an effective CVD risk factor screening tool such as that described here, can help reduce the likelihood that a client will have a cardiac-related adverse event in a fitness center.
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Keywords:© 2013 American College of Sports Medicine.
Preparticipation Screening; Risk Factors; Cardiovascular Disease