PURPOSE To determine if the method of calculating EPOC yields different results prior to and after 9 months of aerobic training in previously sedentary overweight adults. METHODS Forty-three moderate obese college-aged subjects, 26 women (age=24.1±5.5, wt=76.2±10.6kg) and 17 men (age=22.2±4.4, wt=95.0±12.9kg). Exercise progressed from 3d/wk, 30min/session at 60% of heart rate reserve (HRR) to 5d/wk, 45 min/session at 75% of HRR at 4 months and then was maintained until 9 months. Three hour post exercise oxygen consumption was measured baseline and again at 9 months. At baseline subjects walked on a treadmill for 35 min at 65% of HRR. At 9 months subjects walked for 45 min at 75% of HRR. Oxygen consumption was measured 15 min prior to, during, and 15 min subsequent to the exercise bout. In addition, oxygen consumption was measured for 15 min at 60, 120 and 180 min post-exercise. Incremental area under the curve was determined by subtracting the area under the curve at baseline from the total area under the curve. Positive incremental area was calculated the same way as incremental area with negative values being set to zero. RESULTS For women, area under the curve increased 4.61±9.20L, 2.24±6.32L and 1.51±6.32L for the total, positive incremental and incremental methods respectively, while men increased 6.50±13.30L, 2.06±9.47L, 2.08±10.82L. There was no significant main effect for method of analysis and change in post-exercise oxygen consumption after controlling for change in exercise intensity. CONCLUSION The use of total area under the curve instead of incremental or positive incremental area under the curve may be a more sensitive method of detecting change in post-exercise oxygen consumption. This is especially important when attempting to determine the effect of exercise training over time on energy balance, where how much the person changes total energy expenditure may be more important than how much they expended above some baseline value that may or may not reflect a true resting state. Supported by NIH DK49181 and M01 RR00051