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 females. 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 increased during exercise but peaked earlier for the trained women. Lactate concentrations rose over the 20 min and were higher for the trained women. Catecholamine concentration was also higher postexercise when compared to pre-exercise 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. Trained compared to the untrained women tended to show increased plasma glycerol concentrations, earlier during high intensity exercise.

Keywords: intermittent exercise, fat oxidation, RER, catecholamines