A total of 17 participants (30.2 ± 4.8 years; 35.4 ± 4 kg/m²; 38.2 ± 3.6 % body fat) were enrolled in this randomized crossover trial to analyze the effects of a single session of high-intensity interval (HIIE) and moderate-intensity continuous exercise (MICE) on the physical activity and sedentary behavior levels in inactive obese males. The participants performed two exercise sessions and one control session (no exercise): i) low-volume HIIE (10 x 60 s at 90% of maximal aerobic velocity [MAV] interspaced by 60 s at 30% of MAV); ii) MICE (20 min at 70% of maximum heart rate); and iii) control (25 min in a seated position). After all sessions, the physical activity and sedentary behavior levels were monitored by accelerometer over seven consecutive days. No differences in the physical activity (activity counts, and time spent at light, moderate, and vigorous intensities) and sedentary behavior (time spent at sedentary behavior, breaks, and bouts) levels were found among the sessions (HIIE, MICE and control) (p > 0.05). In summary, a single session of HIIE and MICE does not change the physical activity and sedentary behavior levels in inactive obese males. Therefore, low-volume of both high- and moderate-intensity exercise should be considered for inactive obese males given that it does not reduce the physical activity level or increase the time spent at sedentary behavior.

• Low-volume HIIE and MICE does not decrease the habitual physical activity level over one week in inactive obese males.

• Low-volume HIIE and MICE does not increase the sedentary behavior level over one week in inactive obese males.

• Low-volume of both high- and moderate-intensity exercise should be considered to improve health- and fitness-related outcomes in inactive obese males.