Time spent sitting, standing, incidental stepping when not exercising (non-exercise stepping), and exercising as defined by the federal physical activity guidelines. Panels A and B illustrate the results for a cross-sectional comparison between subjects for the mean daily duration of each behavior (A) and the sum of all behaviors accumulated over an entire week (B) for the 3 groups stratified by time spent exercising. Panels C and D illustrate the within subject analysis results comparing the days that subjects had Insufficient exercise (<30 minutes) compared to days where they perform at least 30 minutes of aerobic exercise. Values are expressed as means with SEM bars. * p<0.001 vs. None/Low Exercise or Insufficient Exercise , † p<0.001 vs. Intermediate.