Comparison of lifestyle and structured interventions to increase physical activity and cardiorespiratory fitness - A randomized trial

Context Even though the strong association between physical inactivity and ill health is well documented, 60% of the population is inadequately active or completely inactive. Traditional methods of prescribing exercise have n ot proven effective for increasing and maintaining a program of regular phy sical activity. Objective To compare the 24-month intervention effects of a lifestyle physi cal activity program with traditional structured exercise on improving phys ical activity, cardiorespiratory fitness, and cardiovascular disease risk f actors. Design Randomized clinical trial conducted from August 1, 1993, through Jul y 31, 1997. Participants Sedentary men (n = 116) and women (n = 119) with self-reported physical activity of less than 36 and 34 kcal/kg per day, respectively. Interventions Six months of intensive and 18 months of maintenance interven tion on either a lifestyle physical activity or a traditional structured ex ercise program. Main Outcome Measures Primary outcomes were physical activity assessed by t he 7-Day Physical Activity Recall and peak oxygen consumption (VO2peak) by a maximal exercise treadmill test. Secondary outcomes were plasma lipid and lipoprotein cholesterol concentrations, blood pressure, and body compositi on. All measures were obtained at baseline and at 6 and 24 months. Results Both the lifestyle and structured activity groups had significant a nd comparable improvements in physical activity and cardiorespiratory fitne ss from baseline to 24 months. Adjusted mean changes (95% confidence interv als [CIs]) were 0.84 (95% CI, 0.42-1.25 kcal/kg per day; P<.001) and 0.69 ( 95% CI, 0.25-1.12 kcal/kg day; P=.002) for activity, and 0.77 (95% CI, 0.18 -1.36 mL/kg per minute; P=.01) and 1.34 (95% CI, 0.72-1.96 mL/kg per minute ; P<.001) for VO2peak for the lifestyle and structured activity groups, res pectively. There were significant and comparable reductions in systolic blo od pressure (-3.63 [95% CI, -5.54 to -1.72 mm Hg; P<.001] and -3.26 [95% CI , -5.26 to -1.25 mm Hg; P=.002]) and diastolic blood pressure (-5.38 [95% C I, -6.90 to -3.86 mm Hg; P<.001] and -5.14 [95% CI, -6.73 to -3.54 mm Hg; P <.001) for the lifestyle and structured activity groups, respectively. Neit her group significantly changed their weight (-0.05 [95% CI, -1.05 to 0.96 kg; P=.93] and 0.69 [95% CI, -0.37 to 1.74 kg; P=.20]), but each group sign ificantly reduced their percentage of body fat (-2.39% [95% CI, -2.92% to - 1.85%; P<.001] and -1.85% [95% CI, -2.41% to -1.28%; P<.001]) in the lifest yle and structured activity groups, respectively. Conclusions In previously sedentary healthy adults, a lifestyle physical ac tivity intervention is as effective as a structured exercise program in imp roving physical activity, cardiorespiratory fitness, and blood pressure.