The purpose of this study was to characterise the effects of prolonge d ß-adrenoceptor stimulation on O2 uptake and triglyceride/fatty acid (TG/FA) cycling during rest with and without previous exercise. Eigh t men performed two exercise (90 min cycling at 56 ± 3 (SD) % of maxi mal O2 uptake, followed by 4.5 h bedrest) and two rest-control experi ments. In one rest and one exercise experiment a bolus dose (5 µg) of the ß-adrenoceptor agonist isoprenaline was given immediately after exercise, followed by a continuous infusion (20 ng kg-1 min-1), and a t the corresponding time in the rest experiment. In the other experim ents saline was given instead. The O2 uptake increased in the post-ex ercise period both with and without ß-stimulation. The total excess p ost-exercise oxygen consumption (EPOC) was not different between sali ne (8.1 ± 1.8 (SE) l) and isoprenaline administration (10.8 ± 1.8 l, P = 0.40). Also, the total accumulated increase in O2 uptake for the 4.5 h period after isoprenaline infusion was not different between th e rest (12.5 ± 2.0 l) and the exercise experiments (15.2 ± 1.7 l, P = 0.40). The rate of TG/FA cycling increased after both exercise...
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