Estimating the rate of oxygen consumption during submersion from the heart rate of diving animals

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 2007-05, Vol.292 (5), p.R2028-R2038
• Main Authors: Green, J. A, Halsey, L. G, Butler, P. J, Holder, R. L
• Format: Article
• Language: English
• Subjects: Animals; Cardiology; Diving - physiology; Heart; Heart rate; Heart Rate - physiology; Marine mammals; Models, Biological; Oxygen; Oxygen Consumption - physiology; Spheniscidae - physiology
• ISSN: 0363-6119; 1522-1490
• DOI: 10.1152/ajpregu.00691.2006

1 Department of Zoology, La Trobe University, Bundoora, Melbourne, Australia; and 2 Centre for Ornithology, School of Biosciences and 3 Department of Primary Care and General Practice, University of Birmingham, Edgbaston, Birmingham, United Kingdom Submitted 2 October 2006 ; accepted in final form 3 January 2007 How animals manage their oxygen stores during diving and other breath-hold activities has been a topic of debate among physiologists for decades. Specifically, while the behavior of free-ranging diving animals suggests that metabolism during submersion must be primarily aerobic in nature, no studies have been able to determine their rate of oxygen consumption during submersion ( O 2 D ) and hence prove that this is the case. In the present study, we combine two previously used techniques and develop a new model to estimate O 2 D accurately and plausibly in a free-ranging animal and apply it to data for macaroni penguins ( Eudyptes chrysolophus ) as an example. For macaroni penguins at least, O 2 D can be predicted by measuring heart rate during the dive cycle and the subsequent surface interval duration. Including maximum depth of the dive improves the accuracy of these predictions. This suggests that energetically demanding locomotion events within the dive combine with the differing buoyancy and locomotion costs associated with traveling to depth to influence its cost in terms of oxygen use. This will in turn effect the duration of the dive and the duration of the subsequent recovery period. In the present study, O 2 D ranged from 4 to 28 ml·min –1 ·kg –1 , indicating that, at least as far as aerobic metabolism was concerned, macaroni penguins were often hypometabolic, with rates of oxygen consumption usually below that for this species resting in water (25.6 ml·min –1 ·kg –1 ) and occasionally lower than that while resting in air (10.3 ml·min –1 ·kg –1 ). penguin; model; oxygen stores; hypometabolism Address for reprint requests and other correspondence: J. A. Green, Dept. of Zoology, La Trobe Univ., Bundoora, Melbourne, Victoria, 3086, Australia (e-mail: jon.green{at}latrobe.edu.au )