Exercise training lowers the resting metabolic rate of Zebra Finches, Taeniopygia guttata

1. Although changes in the mass and biochemistry of vertebrate locomotory m uscle are established responses to exercise training, the effects of traini ng on resting metabolic rate (RMR) are not clear. Here, a sustained flight training regime was shown to lower both the night-time and day RMR of capti ve Zebra Finches (Taeniopygia guttata). Training also reduced fat reserves and overall body mass. 2. Our results are largely consistent with the effects of an elevated energ y expenditure on night-time RMR detected in a study of workload on Zebra Fi nches but contrast with most studies of humans, where exercise training inc reases or has no effect upon RMR. 3. A compensatory lowering of RMR in response to increased physical activit y may be an artefact of captivity and could be dependent upon the activity levels of the captives concerned. 4. It is suggested that when extrapolating from cage bird studies to wild s ituations, consideration should be given to the physical condition of the c aged individuals being used. 5. Variation in physical fitness may account for some of the unexplained va riation in comparative studies of basal metabolism.