Research article
Can primary care doctors prescribe exercise to improve fitness?: The step test exercise prescription (STEP) project

https://doi.org/10.1016/S0749-3797(03)00022-9Get rights and content

Abstract

Background

Sedentary lifestyle is associated with adverse health outcomes. Available evidence suggests that, despite positive attitudes toward regular exercise in promoting a healthy lifestyle, few physicians actually prescribe exercise for their patients. Barriers include lack of skills and standard office instruments. Because primary care physicians have regular contact with a large proportion of the population, the impact of preventive health interventions may be great.

Objectives

To determine the effect of an exercise prescription instrument (i.e., Step Test Exercise Prescription [STEP]), compared to usual-care exercise counseling delivered by primary care doctors on fitness and exercise self-efficacy among elderly community-dwelling patients.

Design

Randomized controlled trial; baseline assessment and intervention delivery with postintervention follow-up at 3, 6, and 12 months.

Setting

Four large (>5000 active patient files) academic, primary care practices: three in urban settings and one in a rural setting, each with four primary care physicians; two clinics provided the STEP intervention and two provided usual care control.

Participants

A total of 284 healthy community-dwelling patients (72 per clinic) aged >65 years were recruited in 1998–1999.

Intervention

STEP included exercise counseling and prescription of an exercise training heart rate.

Main outcome measures

The primary outcome measure was aerobic fitness (VO2max). Secondary outcomes included predicted VO2max from the STEP test, exercise self-efficacy (ESE), and clinical anthropometric parameters.

Results

A total of 241 subjects (131 intervention, 110 control) completed the trial. VO2max was significantly increased in the STEP intervention group (11%; 21.3 to 24ml/kg/min) compared to the control group (4%; 22 to 23ml/kg/min) over 6 months (p <0.001), and 14% (21.3 to 24.9ml/kg/min) and 3% (22.1 to 22.8ml/kg/min), respectively, at 12 months (p <0.001). A similar significant increase in ESE (32%; 4.6 vs 6.8) was observed for the STEP group compared to the control group (22%; 4.2 vs 5.4) at 12 months (p < 0.001). Systolic blood pressure decreased 7.3% and body mass index decreased 7.4% in the STEP group, with no significant change in the control group (p <0.05). Exercise counseling time was significantly (p <0.02) longer in the STEP (11.7±3.0min) compared to the control group (7.1±7.0min), but more (p <0.05) subjects completed ≥80% of available exercise opportunities in the STEP group.

Conclusions

Primary care physicians can improve fitness and exercise confidence of their elderly patients using a tailored exercise prescription (e.g., STEP). Further, STEP appears to maintain benefits to 12 months and may improve exercise adherence. Future study should determine the impact of combining cognitive/behavior change strategies with STEP.

Introduction

Despite the strong evidence linking higher levels of physical fitness with improved health and functional outcomes,1, 2, 3, 4 helping patients change their physical activity behaviors is a difficult task for health providers.5, 6 Primary care physicians represent a large pool of professionals who have credibility with their patients and patients list their primary care physician as the desired source for preventive care information.7, 8 Despite this opportunity, research has shown that, for the most part, many physicians do not counsel or monitor their patients’ physical activity behaviors.9, 10 In fact, physicians may counsel less often about exercise than other important health-promoting behaviors.11 Reasons for this discrepancy are many, but likely include lack of time, lack of training, and knowledge about exercise counseling and prescription, including lack of instruments/materials.3, 9, 10, 12

A message from a physician has been shown to be a potent catalyst in motivating change in health behaviors related to exercise.3, 5, 12, 13 The determinants of the physical activity “prescription” have been primarily defined and directed at behavioral change strategies.5, 10, 12, 14, 15, 16, 17 These strategies support high-resource counseling that tailors or matches intensity of physical activity to the stage of readiness to adopt physical activity. The impact of these behavior change interventions alone on increasing physical activity level and fitness in the primary care setting has been variable,18, 19 and suggests a further need to evaluate the components, including the intensity (i.e., degree of resource intensity) of the intervention in the primary care setting.

The Activity Counseling Trial (ACT)20 examined three strategies to improve fitness and physical activity level in the primary care setting. The basic strategy was considered low intensity (i.e., 2- to 4-minute assessment/counseling and goal setting by a physician, followed by referral to a health educator and follow-up telephone reinforcement) compared to the other two strategies, each of which used more intensive counseling. The results showed no change in physical activity at 24 months in any of the groups, and only a small increase in fitness confined to women participants in both of the more intensive intervention groups.20 In an accompanying editorial,21 it was suggested that more intensive strategies may not necessarily improve physical activity or fitness outcome.

Hence, it is unclear whether high-intensity behavior-tailored counseling is a primary determinant of physical activity and fitness in the primary care setting, or whether physicians’ advice can have an impact on significant changes in fitness. It is also unclear whether a lower-intensity strategy designed to prescribe a dose of exercise training, regardless of stage of behavior readiness, by a physician is more effective than high-intensity behavior-change strategies in achieving goals of improving physical activity and fitness in the primary care setting. Specifically, we hypothesized that prescription of a dose of exercise training to increase heart rate to patients delivered by a primary care physician, regardless of matching readiness to change and without sophisticated reinforcement strategies outside the usual care setting, may be a determining factor in achieving change in fitness and associated perceived health outcomes among patients.

Section snippets

Design

The Step Test Exercise Prescription (STEP) project is a randomized controlled trial comparing the effect of assignment to an exercise prescription intervention (hereafter referred to as STEP)22 or published guidelines alone (hereafter referred to as control) on fitness among elderly, community-dwelling, healthy patients. Secondary aims were to compare effects of the intervention on predicted fitness, exercise self-efficacy (ESE), clinical anthropometric measures (including body mass index

Recruitment

Recruitment of participants was conducted over a 6-month period (Figure 1) . During a 2-month period of opportunistic patient recruitment, 76 patients (range 1 to 12 per practice) were identified out of 868 total patient encounters (8.7%), thus meeting entry criteria. An additional 424 patients meeting the entry criteria were identified from the patient databases in the clinics over the next 4 months. Potential subjects were then screened until a cell of 80 recruits per site (320 total) was

Discussion

The STEP group experienced an 11% improvement in fitness since baseline, compared to a 4% improvement in the usual-care exercise-counseling control group. Similar differences in measures of ESE, systolic blood pressure, and BMI were observed in the STEP group compared to the control group at 12 months. These changes were notable given the absence of a maintenance program or complementary matched behavior–change strategy. Indeed, the gains made in STEP by 6 months were maintained to 12 months,

Acknowledgements

We are grateful to Becky Quinlan and Brad Hansen for their technical assistance. This study was supported by a grant from Medical Research Council of Canada/Pharmaceutical Manufacturers Association of Canada (95401). RJP is supported by a Canadian Institutes of Health Research/Rx&D Research Program investigator award (95000).

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