Activity before exercise influences recovery metabolism in the lizard Dipsosaurus dorsalis

During recovery from even a brief period of exercise, metabolic rate remain s elevated above resting levels for extended periods. The intensity and dur ation of exercise as well as body temperature and hormone levels can influe nce this excess post-exercise oxygen consumption (EPOC). We examined the in fluence of activity before exercise (ABE), commonly termed warm-up in endot herms, on EPOC in the desert iguana Dipsosaurus dorsalis. The rate off oxyg en consumption and blood lactate levels were measured in 11 female D. dorsa lis (mass 41.1+/-3.0 g; mean +/- S.E.M.) during rest, after two types of AB E and after 5 min of exhaustive exercise followed by 60 min of recovery. AB E was either single (15 s of maximal activity followed by a 27 min pause) o r intermittent (twelve 15 s periods of exercise separated by 2 min pauses). Our results indicate that both single and intermittent ABE reduced recover y metabolic rate. EPOC volumes decreased from 0.261 to 0.156 ml of oxygen c onsumed during 60 min of recovery when lizards were subjected to intermitte nt ABE. The average cost of activity (net (V) over dot O-2 during exercise and 60 min of recovery per distance traveled) was almost 40% greater in liz ards that exercised without any prior activity than in lizards that underwe nt ABE. Blood lactate levels and removal rates were greatest in animals tha t underwent ABE. These findings may be of particular importance for terrest rial ectotherms that typically use burst locomotion and have a small aerobi c scope and a long recovery period.