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 non-exercise physical activity on body composition and cardiometabolic risk factors.
Obese adults (N=45) were randomized to 6-months of aerobic training (AERO), aerobic training and increasing non-exercise physical activity (~3,000 steps above baseline levels) (AERO-PA), or a control group (CON). 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 non-exercise physical activity.
There was a larger increase in fitness in the AERO-PA group (0.27 L/min, 0.16 to 0.40) compared to the AERO group (0.09 L/min, CI: -0.04 to 0.22) and the CON (0.01, CI: -0.11 to 0.12) groups. While 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-hr glucose and 2-hr insulin in comparison to the CON group (p<0.05), but not the AERO group. Further, 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.
Increasing non-exercise 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.