Physical activity is a routine component of the lifestyle modification program implemented prior to bariatric surgery, and one of the goals is to improve patients' physical capacity. However, the physical activity intensity recommended to meet that goal is unknown. This study aimed to assess the association between time spent at different physical activity intensities and physical capacity in patients awaiting bariatric surgery. A total of 39 women and 13 men were recruited. The primary outcome was physical capacity measured using six objective tests: 6-min walk, chair stand, sit and reach, unipodal balance (eyes open and eyes closed), and hand grip strength tests. The primary exposure variable was physical activity intensity (i.e., sedentary, light, moderate, and vigorous) measured by accelerometers. The average body mass index was 46.3 +/- 5.4 kg/m(2). Only 6% of total time was spent at moderate to vigorous intensity, while 71% of the time was spent sedentary. When adjusted for body mass index, age, and sex, four of the six physical capacity tests were significantly associated with moderate intensity physical activity beta(SE): 6-min walk 9.7 (2.7), chair stand 0.3 (0.1), balance (eyes open) 1.8 (0.7), and hand grip strength 1.2 (0.4), and only the 6-min walk was associated with sedentary activity 1.7 (0.7). These results suggest that physical capacity is associated with time spent at moderate intensity in individuals awaiting bariatric surgery. The next step is to study if an increase in time spent at moderate intensity will translate to improvements in physical capacity.