To Örebro University

Introduction High intensity interval exercises are an efficient way to produce high energy expenditure (EE) not only during, but also after exercise with the contribution of excess post-exercise oxygen consumption (EPOC). Meanwhile, combining weight and aerobic exercise could also have beneficial effects on body composition. Therefore, high intensity interval exercising including weight exercises could be relevant for individuals with limited time. The aim of this study was to compare EE and EPOC between a high intensity cycling exercise (HICE) and two high intensity weight exercise (HIWE) sessions with different loads.Material & methods Sixteen healthy adults (25,6±3,2 years) randomly completed three different exercise sessions; HICE, HIWE with low load (HIWE40) and HIWE with moderate load (HIWE60). The high intensity interval exercise sessions consisted of two sets of ten 30s intervals (power at 100% VO2max during HICE; maximal number of repetitions for 10 different exercises during HIWE) separated by 30s recovery. EE was determined from indirect calorimetry during exercise, and 12 minutes post-exercise. Blood lactate concentration and rating of perceived exertion were measured after each set, and total load lifted was calculated.Results The combined EE for sets was significantly higher in HICE (282,4±51,7 kcal) than HIWE40 (187,8±33,1 kcal) and HIWE60 (198,4±39 kcal, p<0,001), with no significant differences between HIWE sessions. No significant differences were observed in post-exercise EE or EPOC between sessions. Lactate concentration was significantly higher in HIWE60 than in HICE after sets (p<0,01). Rating of perceived exertion was significantly lower after set1 in HIWE40 (15,69±1,85 arb.unit) than HICE (17,19±0,98 arb.unit, p<0,01) and HIWE60 (17,38±1,15 arb.unit, p<0,001). Total load lifted was similar between weight exercise sessions.Conclusions HICE elicits greater acute energy expenditure in comparison to HIWE at different loads. Furthermore, for those who prefer to weight exercising, using low loads elicits similar EE as moderate loads despite being perceived as less exertional.