Two Minutes of Sprint-Interval Exercise Elicits 24-hr Oxygen Consumption Similar to That of 30 min of Continuous Endurance Exercise

• DOI: 10.1123/ijsnem.22.4.276
• Publication Date: 2016-08-10T12:32:34Z
• Authors: Tom J. Hazell; T. Dylan Olver; Craig D. Hamilton; Peter W. R. Lemon
• Keywords: Adult; Male; Time Factors; Carbon Dioxide; Running; Young Adult; 03 medical and health sciences; Oxygen Consumption; 0302 clinical medicine; Respiratory Rate; Heart Rate; Exercise Test; Physical Endurance; Humans; Exercise

Six weeks (3 times/wk) of sprint-interval training (SIT) or continuous endurance training (CET) promote body-fat losses despite a substantially lower training volume with SIT. In an attempt to explain these findings, the authors quantified VO2 during and after (24 h) sprint-interval exercise (SIE; 2 min exercise) vs. continuous endurance exercise (CEE; 30 min exercise). VO2 was measured in male students (n = 8) 8 times over 24 hr under 3 treatments (SIE, CEE, and control [CTRL, no exercise]). Diet was controlled. VO2 was 150% greater (p < .01) during CEE vs. SIE (87.6 ± 13.1 vs. 35.1 ± 4.4 L O2; M ± SD). The observed small difference between average exercise heart rates with CEE (157 ± 10 beats/min) and SIE (149 ± 6 beats/min) approached significance (p = .06), as did the difference in peak heart rates during CEE (166 ± 10 beats/min) and SIE (173 ± 6 beats/min; p = .14). Total O2 consumed over 8 hr with CEE (263.3 ± 30.2 L) was greater (p < .01) than both SIE (224.2 ± 15.3 L; p < .001) and CTRL (163.5 ± 16.1 L; p < .001). Total O2 with SIE was also increased over CTRL (p < .001). At 24 hr, both exercise treatments were increased (p < .001) vs. CTRL (CEE = 500.2 ± 49.2; SIE = 498.0 ± 29.4; CTRL = 400.2 ± 44.6), but there was no difference between CEE and SIE (p = .99). Despite large differences in exercise VO2, the protracted effects of SIE result in a similar total VO2 over 24 hr vs. CEE, indicating that the significant body-fat losses observed previously with SIT are partially due to increases in metabolism postexercise.