EXCESS POSTEXERCISE OXYGEN CONSUMPTION (EPOC) FOLLOWING AEROBIC EXERCISE TRAINING

Abstract

No researchers have conducted longitudinal studies examining the effect of aerobic exercise training on EPOC. For this study, 20 untrained male volunteers were randomly assigned to an aerobic (jog/run) exercise (EX: n = 10) or no exercise (CON: n = 10) group for 12 weeks. Complete data were obtained for 9 subjects in each group and are as follows: Mean (SEM) age, wt, body fat, and VO2max for EX and CON = 26.2 (1.4) and 26.2(0.9) y, 73.8(2.1) and 71.2(2.7) kg, 16.4(1.7) and 17.7(1.1) %, 46.2(1.2) and 45.1(1.4) ml·kg−1·min−1, respectively. Subjects ran on a treadmill for 30 min at 70% VO2max (REL) pre (PRE)-and post (POST)-training. Subjects in EX also exercised POST for 30 min at the same absolute (ABS) intensity as PRE. VO2 was measured for 10 min following a 30 min seated rest, continuously during exercise and the first 30 min of recovery, and for the last 10 min of every 30 min for an additional 90 min. Norepinephrine (NOR), epinephrine (EPI), free fatty acids (FFA), glucose (GLU) and insulin (INS) were measured at rest, end-exercise (END), and at various time points during recovery. Data were analyzed using mixed factorial ANOVAs and multiple comparison post hoc tests at alpha = 0.05. VO2max increased 10.3% in EX from PRE to POST. EPOC was significantly lower POST [133(9) kJ] than PRE [167(15) kJ] for the ABS but not the REL trial. EPI (pg·ml−1) at END was significantly lower POST [ABS = 73.8(10.1), REL = 76.3(11.2)] than PRE [102.5(22.4)], whereas NOR (pg·ml−1) was higher POST [1416.8(182.5)] than PRE [1114.4(190.6)] for REL only. FFA (mmol·l−1) POST were higher at END [ABS = 0.81(0.14), REL = 0.78(0.09)] and 30 min REC [ABS = 0.94(0.11), REL = 0.92(0.11)] than PRE [END = 0.53(0.08), 30 min REC = 0.59(0.07)]. GLU POST was lower than PRE at END and 30, 60 and 120 min REC during both trials, and at rest during ABS. INS during both trials was lower POST than PRE at rest, END, and 30 and 60 min REC. The only difference in CON was higher NOR at end-exercise POST [1300.8(183.6)] than PRE [1047.4(87.7)]. The various blood nutrients and hormones measured in this study have been suggested to impact the EPOC response. Although these analytes were significantly altered as a result of exercise training, EPOC was not uniformly affected across two different intensities of exercise.