Metabolic response of trained and untrained women during high-intensity intermittent cycle exercise

Abstract

The metabolic response to two different forms of high-intensity intermittent cycle exercise was investigated in young women. Subjects (8 trained and 8 untrained) performed two bouts of high-intensity intermittent exercise: short sprint (SS) (8-s sprint, 12-s recovery) and long sprint (LS) (24-s sprint, 36-s recovery) for 20 min on two separate occasions. Both workload and oxygen uptake were greater in the trained subjects but were not significantly different for SS and LS. Plasma glycerol concentrations significantly increased during exercise. Lactate concentrations rose over the 20 min and were higher for the trained women. Catecholamine concentration was also higher postexercise compared with preexercise for both groups. Both SS and LS produced similar metabolic response although both lactate and catecholamines were higher after the 24-s sprint. In conclusion, these results show that high-intensity intermittent exercise resulted in significant elevations in catecholamines that appear to be related to increased venous glycerol concentrations. The trained compared with the untrained women tended to show an earlier increase in plasma glycerol concentrations during high-intensity exercise. intermittent exercise; catecholamines; glycerol; lactate STEADY-STATE, MODERATE-INTENSITY aerobic exercise has been recommended for fat loss because the proportion of lipid in the fuel oxidized during low-intensity physical activity is greater than during high-intensity exercise (25). However, it has been shown that individuals engaging in vigorous exercise were leaner than those participating in less intense exercise (31). The ability of high-intensity exercise to cause negative energy balance was also shown by a 15-wk high-intensity intermittent exercise (HIIE) program that resulted in a greater decrease in skinfold thickness relative to energy expenditure compared with 20 wk of endurance exercise (32). The HIIE in this study consisted of short (15-30 s) and long (60 -90 s) sprints separated by recovery periods (1-2 min) allowing the heart rate (HR) to return to 120 -130 beats/min. The energy cost of the HIIE was less than half of that of the endurance program. Thus, despite using half the energy, the impact of the HIIE program, compared with steady-state exercise, on subcutaneous adiposity was significantly greater. However, the effects of HIIE on the components of energy balance were undetermined. Thus how HIIE may cause significant reductions in adiposity is unknown. Possible mechanisms include factors affecting energy intake (24) and postexercise energy expenditure (32).It is feasible that participating in repeated bouts of HIIE could influence postexercise energy expenditure. For example, HIIE is likely to result in a significant elevation of catecholamines (35), which have been shown to elevate postexercise energy expenditure. However, the metabolic response during one bout of HIIE is unclear. For example, when and if free fatty acids (FFAs) are utilized during HIIE is undetermined. Also the catecholamine response and th...

The effects of high-intensity intermittent exercise training on fat loss and fasting insulin levels of young women

“…Prior research in our laboratory has shown that lipid release, as indicated by blood glycerol levels, gradually increased over 20 min of HIIE. 20 Catecholamine levels in this study were also found to be significantly elevated after HIIE. 20 With regard to SSE, the FM and aerobic fitness response was typical of that reported in the literature in that there were no significant changes in TBM, FM or trunk fat, but there was a significant increase in aerobic fitness.…”

“…20 Catecholamine levels in this study were also found to be significantly elevated after HIIE. 20 With regard to SSE, the FM and aerobic fitness response was typical of that reported in the literature in that there were no significant changes in TBM, FM or trunk fat, but there was a significant increase in aerobic fitness. [26][27][28][29][30][31][32] Central adiposity diminished in the HIIE compared to the SSE and CONT groups.…”

“…¼ W) into oxygen consumption in l min À1 . 19 Energy expenditure for one session of HIIE was assessed in a previous study, 20 and this data was used to estimate energy expenditure for the 15 weeks of HIIE of the present study. Using this method, there was no significant difference between SSE (36.3±3.4 MJ) and HIIE (41.5±0.81 MJ) in estimated total energy expenditure over the 15-week training period.…”

The Combined Effect of Short Term Green Tea Extract and a Single Bout of Cycle Ergometer on Glycerol and Free Fat Acid of Trained Males

“…Consistent with this study, several studies reported that there were no marked changes between lipid profile concentrations following green tea intake (12,13). In contrast, Hsu et al (14) reported that green tea intakes significantly decreased low density lipoprotein (LDL)-cholesterol and increased high density lipoprotein (HDL) cholesterol concentrations.…”

Analýza efektu vysoce intenzivního intervalového tréninku (HIIT)

“…Reakce má totiž podle dalších autorů (Issekutz, 1978;Bracken, 2009;Laforgia, 2006) být stěžejní pro tento typ cvičení. Studie (Issekutz, 1978;Christmas, 1999;Trapp, 2007;Boutcher, 2010;Vincent, 2004) prokázaly, že epinefrin (adrenalin) řídí lipolýzu a zčásti zodpovídá za uvolňování tukových zásob z podkožních a intramuskulárních oblastí.…”