Physical activity counseling in primary care: the challenge of effecting behavioral change.

Abstract

LOW LEVELS OF PHYSICAL ACTIVITY AND FITNESS ARE ASsociated with a 2-fold increase in risk of all-cause and cardiovascular mortality. The cardiovascular and mortality risk associated with low physical fitness is similar to, and in some cases higher than, the risk attributable to diabetes mellitus, high cholesterol levels, hypertension, or cigarette smoking. Yet only 15% of adults engage in regular vigorous physical activity, and 60% report no regular or sustained leisure time activity. The benefits of physical activity are undisputed. Numerous epidemiological studies suggest a dose-response relationship between higher physical activity and fitness levels and lower mortality risk. Observational evidence suggests that improvements in physical fitness and activity level prolong survival. In addition, recent randomized trials have demonstrated the beneficial effects of moderate levels of regular physical activity on cardiovascular risk factors, such as insulin resistance, hypertension, and obesity. Yet despite this strong evidence, US physicians advise only a minority of their patients about physical activity. Patients at highest risk for weight gain and poorer health outcomes, such as sedentary adults and those with lower income, are least likely to receive physical activity counseling. Several barriers prevent physicians from counseling patients about physical activity, including limitations in time and resources and the perceived ineffectiveness of counseling. While physical training may improve fitness levels, based on the evidence currently available it is not clear whether primary care–based interventions for improving physical activity are effective. The majority of earlier studies have been small or poorly controlled, and although many suggest positive findings in the short term, their methodological shortcomings limit the interpretability of results. The findings of more recent trials have been inconsistent. The Johns Hopkins Medicare Preventive Services Project, which examined the effect of preventive health examinations in an elderly population (n=3097), found no increase in physical activity level at 1 year among those randomized to receive physical activity counseling. The OXCHECK trial randomized 2205 patients in England to receive usual care or physical activity counseling and 5 follow-up visits by trained nurses. After 3 years, a small but statistically significant proportion of the intervention group (32.4%) compared with the control group (29.1%) reported performing vigorous exercise more than once a month. Unfortunately, physical activity level was not measured in a more precise way in this study; the benefit of vigorous exercise once a month is unclear. The Activity Counseling Trial (ACT) reported in this issue of THE JOURNAL adds to the literature on the effectiveness of physical activity counseling in the primary care setting. A volunteer sample of 874 sedentary patients from 11 primary care facilities was randomly assigned to receive 1 of 3 physical activity counseling interventions of varying intensity. The study assessed 2 primary outcomes: (1) physical activity or total energy expenditure as estimated by a 7-day Physical Activity Recall (PAR) interview of specific activities and (2) cardiorespiratory fitness (VO2max) as measured by a graded maximal exercise test. Unfortunately, the ACT does not directly address a central question—whether physical activity counseling by clinicians in primary care settings increases physical activity or improves cardiorespiratory fitness levels. Rather, this study addresses whether high-intensity counseling and behavioral support provided by health educators in a primary care setting improve activity and fitness levels when compared with more modest counseling efforts. The advice or comparison group in the ACT received a higher level of physical activity counseling from their physicians (who were trained in assessing physical activity, providing advice, and selecting a long-term goal) than is currently usual care. These patients also received an average of 3 brief counseling contacts from health educators over a 2-year period. The assistance group received the same advice care from their phy-