This study examined the effect of a moderate intensity exercise training program on daily physical activity levels of previously sedentary and habitually active adults. Previously sedentary subjects wore a pedometer while completing a seven consecutive day baseline physical activity measurement. After the seven day baseline trial, they received a traditional exercise prescription for 6 weeks while continuing to wear the pedometer every day. Habitually active subjects wore a pedometer for seven consecutive days while continuing their normal daily and exercise routines. Results showed that the previously sedentary subjects increased their physical activity levels by approximately 2,000 steps/day after starting a structured exercise program. On the non-exercise days, there was little to no change in physical activity levels (7,354 ± 2,344 steps/day) for the sedentary subjects when compared to the baseline daily physical activity levels (7,232 ± 1,692 steps/day). The habitually active group showed significantly higher (p<0.05) physical activity levels (12,389 ± 3,391 steps/day) when compared to the sedentary group's 6h week physical activity levels (9,697 ± 2,212 steps/day). In addition, the habitually active group showed similar physical activity levels on non-exercise days (8,780 ± 3,295 steps/day) when compared to the sedentary group's 6h week physical activity on non-exercise days (7,354 ± 2,344 steps/day). In conclusion, in previously sedentary subjects, a moderate intensity exercise program resulted in a significant increase in daily physical activity but not to the level of the habitually active subjects.