The American Heart Association [2] recently added "sedentary lifestyle" to its list of controllable risk factors. The American College of Sports Medicine and the Centers for Disease Control and Prevention (CDC) suggest that all Americans should accumulate 30 minutes or more of moderate-intensity physical activity on most, preferably all, days of the week [3]. The National Institutes of Health (NIH) recently issued similar recommendations [4]. However, the NIH stressed that persons currently meeting this standard can derive additional health and fitness benefits by becoming more physically active or participating in more vigorous activities.

Getting Patients Moving

Getting patients moving is always a challenge. The subject of physical activity should be broached with sedentary patients at the first office visit. Say, for example, "It must be hard to stay physically active with all the time you need to spend at a desk job." This beginning can lead easily to information on the patient's attitudes and beliefs about exercise and whether he or she wants to begin an exercise program. Many sedentary patients would like to become more active but do not know how to begin.

Obtain a history of exercise habits and sports participation over a lifetime. This can help identify the type of activity to suggest. For example, a former varsity athlete who enjoyed regular exercise and training may feel comfortable with a traditional prescription for structured exercise in a health club. Conversely, a program of increased lifestyle activity may initially be more appropriate for a sedentary, middle-aged patient with no formal exercise history. It is also helpful to identify the person's current exercise pattern (that is, the exercise pattern over the past 3 to 6 months) and barriers to participation (Table 1). Characterizing social preferences may also help tailor the exercise prescription. For example, some enjoy the solitude of walking or jogging; others enjoy the camaraderie of an exercise class.

It is common for the press to emphasize stories about the exercise-related tragedies of elite athletes who succumb to sudden cardiac death. Thus, it is important to address patient fears related to exercise [5]. Patients should understand that, in reality, regular physical activity is associated with a decreased risk for heart disease. Furthermore, the risk for sudden death with moderate-intensity activity is considerably less than the risk with more intense vigorous exercise [1].

It is important for physicians to state clearly the medical importance of physical activity. Patients may perceive that physicians who do not address the need to exercise are condoning a sedentary lifestyle. On the other hand, a clear statement that addresses the health benefits and importance of increasing physical activity conveys the message that sedentary habits are bad habits.

Once the stage is set, it is best to establish small, attainable initial goals with the patient. For example, after establishing baseline levels of physical activity, a first step is to recommend increased lifestyle activity. The prescription should be very specific, achievable, and realistic (for example, walk five blocks and walk up three extra flights of stairs each day) and should be developed in discussion with the patient. Writing the recommendation on a prescription pad may increase the likelihood that the recommendation will be followed. At follow-up visits, ask patients if they have successfully met their goals. Any increase is a step in the right direction and should be praised. With time and encouragement, many persons find that what they were initially doing largely to please others (such as the physician) becomes rewarding and self-reinforcing as they perceive improvements in physical fitness, energy level, mood, and health.

Effects of Physician Advice

Helping patients change modifiable risk factors is a difficult task for health care providers [6-8]. Because patients respect their physician's advice, a succinct message from a physician can be a potent catalyst in motivating change [9, 10]. Fully 80% of Americans cite their physician as their primary source of information about health [11], and the average adult makes 2.7 visits to a physician per year; thus, the physician has multiple opportunities to intervene and encourage patients to adopt healthier lifestyles [12]. The U.S. Preventive Services Task Force [9] recommends that physicians advise patients to engage in a program of regular physical activity tailored to their individual health status and lifestyle [9].

Although the conviction that physician counseling to increase physical activity may have a significant effect on public health is widespread, only limited empirical evidence supports it [9]. One major study, the PACE (Physician-Based Assessment and Counseling for Exercise) program, was developed to provide specific counseling protocols matched to the patient's level of activity and readiness to change. Long and colleagues [13] found that 3- to 5-minute counseling sessions increased physical activity among patients treated in the primary care setting. Eighty percent of providers in the PACE trial reported that their patients were "receptive" or "very receptive" to activity counseling. More than 50% of providers perceived that their patients became more active after the intervention.

In one randomized trial [10], increases in the duration (but not the frequency) of physical activity were reported a month after physician activity counseling [10]. Patients in this trial were also asked to report their level of agreement with the following statement: "If my doctor advised me to exercise, I would follow his/her advice." Thirty-five percent of patients strongly agreed and 58% agreed with this statement, whereas only 7% disagreed and less than 1% strongly disagreed.

Investigators in a multicenter cohort study assessed changes in several health-related behaviors 1 year after a preventive intervention by primary care physicians. Surveys conducted before and after the intervention showed that study patients with behavioral risks who had the intervention were more likely than matched controls to report positive changes with regard to exercise adoption, use of seatbelts, weight loss, and reduction of alcohol intake [14].

Although physicians generally believe that most patients should exercise, many of those who counsel their patients about health-habit modifications address smoking and body weight more frequently than they address inactivity [15]. For example, Rosen and coworkers [16] reported that although 64% of primary care physicians prescribed exercise for their high-risk patients, only 29% regularly counseled all patients about the importance of regular activity. Patients often interpret a lack of advice to become more active as an endorsement of the view that physical activity is not important.

Recommendations about Physical Activity

Early guidelines specified that aerobic exercise would offer little benefit if it were not done at moderate to high intensity in a steady state for 20 to 60 minutes three or more times per week [17]. These rigorous recommendations were designed to achieve optimal improvements in physical fitness. Persons currently exercising at this level should be encouraged to continue because this activity is likely to maximize both health and fitness benefits. However, the current low rate of volitional participation in exercise may be due in part to the misunderstanding that exercise must be vigorous and uninterrupted in order to provide health benefits [3].

Physical activity is defined as "any bodily movement produced by skeletal muscles that results in energy expenditure" [18]. Physical fitness is related to, but distinct from, physical activity. It is defined as "a set of attributes that people have or achieve that relates the ability to perform physical activity" [18]. Fit persons have a lower risk for cardiovascular disease [19, 20]. In 1989, Blair and colleagues [19] demonstrated that adults with low cardiorespiratory fitness had much higher rates of all-cause and cardiovascular mortality than did those who were moderately fit. Smaller but additional reductions in death rates were seen in persons who were the most fit. Thus, physical activity need not be vigorous or extensive to produce substantial health benefits.

Recent reports document that the health benefits of increasing activity can be accrued at exercise intensities significantly lower than previously thought [18-20]. These findings prompted the NIH [4], the CDC and the American College of Sports Medicine [3], and the Surgeon General [1] to revise exercise guidelines. It is now suggested that sedentary persons who wish to become more physically active should accumulate 30 minutes or more of moderate-intensity physical activity each day as an alternative to traditional programmed exercise.

In 1993, Paffenbarger and colleagues [21] reported the effects of changes in physical activity and other lifestyle characteristics on mortality in 10 269 Harvard University alumni. Men who were initially sedentary but had started to participate in moderately vigorous sports by 1977 had a 23% lower risk for death than did those who remained inactive. Of note, reductions in any of four risk indicators-smoking, obesity, hypertension, or physical inactivity-seemed to make a similar and significant contribution to risk reduction.

Changes in cardiorespiratory fitness were examined in 9777 men who had two preventive medicine examinations [22]. Men who were unfit at both assessments had the highest all-cause mortality rates, those who were fit at both assessments had the lowest rates, and those who improved their fitness status to at least a moderate level had intermediate rates (44% lower age-adjusted risk for death from all causes compared with the group that remained unfit).

A major drawback of the traditional exercise prescription is the emphasis on an exercise threshold. Health and fitness professionals convinced the public that exercise was beneficial only when the heart rate was elevated to a target range (for example, 60% to 80% of maximal heart rate). This left many persons feeling that exercise that was not done in a health club or at greater than moderate intensity was of little or no benefit.

It is now widely recognized that moderate-intensity activity also confers health benefits. For most sedentary persons, moderate-intensity activity equals a 3- to 4-mph walk. The change in emphasis from vigorous to moderate exercise is especially important. First, it is easier and safer for sedentary persons to adopt and adhere to a program of moderate-intensity activity. Second, with 40 million Americans currently inactive, even small amounts of activity among this large population would have a substantial effect on public health. Third, moderate-intensity activity often serves as a gateway to more traditional exercise programs.

Perceived lack of time is the most commonly cited barrier to participation in regular physical activity [1]. For many, finding a block of time to devote to exercise is difficult; however, exercise is effective whether it is completed in a single bout or split into briefer segments. For instance, 30 minutes of moderate-intensity activity per day could be accomplished by a single 30-minute walk or three 10-minute walks [23, 24]. Thirty minutes of activity could also be accumulated throughout the day by taking the stairs in lieu of the elevator, walking instead of driving short distances, using fewer labor-saving devices, and doing housework or yardwork [25, 26]. Many persons can readily insert shorter bouts of lifestyle activity into busy schedules. This point is worth emphasizing because the current low rate of participation in exercise may be due to the misperception that exercise must be uninterrupted in order to confer benefit.

A theoretical model of increasing lifestyle activity is shown in the Figure 1 [26]. The goal of the lifestyle model is to accumulate the same area-under-the-curve (representing total energy expenditure) as the traditional exercise model. It is often easier to accomplish this than to devote a fixed block of time to programmed exercise.

View larger version (20K): [in this window] [in a new window]   Figure 1. Energy expenditure. The solid line indicates the energy expenditure over the course of a day for a sedentary person; the dashed line represents the energy expenditure of a person who engages in planned, vigorous exercise during leisure time but is otherwise sedentary; and the dotted line illustrates the energy expenditure of a person with a sedentary job who seeks opportunities to accumulate short bouts of physical activity throughout the day. Reproduced from Blair and associates [26] with permission of Blackwell Scientific.

Most of the research on physical activity and health has focused on aerobic activities. However, resistance exercise was added to the 1990 American College of Sports Medicine position statement on exercise prescription for healthy adults [27]. The health benefits of resistance training are numerous [28-31]. Fiatarone and colleagues [32] showed substantial increases in physical function in very elderly persons who participated in resistance training. Two resistance-training workouts each week are recommended to attenuate the muscle atrophy and bone loss that accompany aging in many adults.

Encouraging Adherence to Exercise Programs

Despite the best intentions, many persons who begin an exercise program will not stay with it over time. In one study [5], half of all adults who began or renewed an exercise program failed to maintain it at the level they had intended. In a typical supervised setting, about 50% of persons drop out within 6 months to 1 year [33]. Thus, an exercise or activity program should focus not only on decreasing current sedentary living habits but also on promoting long-term adherence [1].

A physician's active interest and encouragement in how the patient is succeeding in becoming more physically active can be very helpful in increasing adherence. Long-term adherence is related to support from friends, exercise leaders, family [33], and especially spouses [5]. Although the personal benefits to the patient will be self-evident, the additional encouragement of the physician is a potent reinforcer. Needless to say, even small steps in the right direction are helpful and worthy of recognition; the physician can become a vital link in the patient's personal support network [34].

Persons who are aware of the health benefits of exercise are more likely to become regular exercisers [35]. Printed materials and a list of suggested books and videotapes can allow patients to educate themselves, which leads to enhanced adherence. Periodic feedback on health improvements related to lifestyle improvement can result in renewed enthusiasm. Recording prescribed physical activity in patient charts can help with follow-up office visits and exercise-related discussions. Resting heart rate, blood pressure, body weight, and waist circumference are all inexpensive, quick assessments that are usually included as part of the physical examination and are a likely response to increased exercise. Improved serum lipid and lipoprotein profiles also often accompany a moderate-intensity exercise program [36].

Sedentary persons who begin by exercising at moderate intensities are more likely to adhere to their programs than are those who begin by exercising vigorously [35]. Exercising 5 days or more per week or exercising at intensities that the patient perceives as "hard" may also lead to higher dropout rates [15]. Exercise-related injuries are also likely to increase the risk for dropping out of vigorous exercise programs [5, 33]. Scientific evidence suggests that most exercise-related injuries are preventable [9]. Patients should be encouraged to engage in a low- to moderate-intensity warm-up before exercise. Limiting increases in the duration or intensity of training sessions to 5% per week will help reduce the risk for injury.

As mentioned above, a perceived lack of time is one of the most common reasons cited by Americans for not exercising [1, 33]. Let patients know that three programmed workouts per week for a minimum of 20 minutes of vigorous exercise is the standard prescription, but doing something is better than doing nothing. Remember that new guidelines encourage adults to accumulate 30 minutes of activity throughout the day; this is often easier for persons to work into busy schedules. Patients are often able to find more time for exercising after they become active and notice results. Encouraging patients to make appointments to exercise (even with themselves) can be helpful. Exercising with others can also enhance commitment because it is harder to "forget" exercise when someone else is involved.

In short, sedentary living is a serious and pervasive health problem in the United States [1, 4]. Changing health behaviors can be a slow process but is well worth the effort. If a patient does not make suggested changes between office visits, it does not mean that the physician's message is lost. A patient often needs to hear a given message repeatedly to make a change. By reiterating the importance of physical activity during each office visit, the physician confirms the importance of an active lifestyle. Stressing the importance of regular activity will increase both longevity and quality of life in patients who abandon their sedentary ways. Physicians who set a good example themselves further enhance the importance of the message they wish to send to patients.

Dr. Blair: Cooper Institute for Aerobics Research, 12330 Preston Road, Dallas, TX 75230.