The Effect of Aerobic Training and Increasing Nonexercise Physical Activity on Cardiometabolic Risk Factors.

PURPOSE: Epidemiological studies suggest that sedentary behavior is an independent risk factor for cardiovascular mortality independent of meeting physical activity guidelines. However, limited evidence of this relationship is available from prospective interventions. The purpose of the present study is to evaluate the combined effect of aerobic training and increasing nonexercise physical activity on body composition and cardiometabolic risk factors. METHODS: Obese adults (N = 45) were randomized to 6 months of aerobic training (AERO), aerobic training and increasing nonexercise physical activity (~3000 steps above baseline levels; AERO-PA), or a control (CON) group. The AERO and AERO-PA groups performed supervised aerobic training (3-4 times per week). The AERO-PA group wore Fitbit One accelerometers and received behavioral coaching to increase nonexercise physical activity. RESULTS: There was a larger increase in fitness in the AERO-PA group (0.27 L·min-1; confidence interval (CI), 0.16 to 0.40 L·min-1) compared with the AERO group (0.09 L·min-1; CI, -0.04 to 0.22 L·min-1) and the CON group (0.01; CI, -0.11 to 0.12 L·min-1). Although significant findings were not observed in the entire study sample, when the analysis was restricted to participants compliant to the intervention (n = 33), we observed significant reductions in waist circumference, percent weight loss, body fat, 2-h glucose, and 2-h insulin in comparison to the CON group (P < 0.05), but not the AERO group. Furthermore, linear regression models showed that change in steps was associated with 21% and 26% of the variation in percent weight loss and percent fat loss, respectively. CONCLUSIONS: Increasing nonexercise physical activity with aerobic training may represent a viable strategy to augment the fitness response in comparison to aerobic training alone and has promise for other health indicators.

The intervention composed of aerobic training and non-exercise physical activity (I-CAN) study: Rationale, design and methods.

Recent data has suggested that prolonged sedentary behavior is independent risk factor for cardiovascular and all-cause mortality independent of adequate amounts of moderate to vigorous physical activity. However, few studies have prospectively evaluated if exercise training and increasing non-exercise physical activity leads to greater reduction in cardiometabolic risk compared to aerobic training alone. The purpose of the Intervention Composed of Aerobic Training and Non-Exercise Physical Activity (I-CAN) study is to determine whether a physical activity program composed of both aerobic training (consistent with public health recommendations) and increasing non-exercise physical activity (3000 steps above baseline levels) leads to enhanced improvements in waist circumference, oral glucose tolerance, systemic inflammation, body composition, and fitness compared to aerobic training alone in obese adults (N=45). Commercially available accelerometers (Fitbits) will be used to monitor physical activity levels and behavioral coaching will be used to develop strategies of how to increase non-exercise physical activity levels. In this manuscript, we describe the design, rationale, and methodology associated with the I-CAN study.