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Ventilatory and cardiovascular responses of a python (Python molurus) to exercise and digestion
S.M. Secor, J.W. Hicks, A.F. Bennett
Journal of Experimental Biology 2000 203: 2447-2454;

Summary

To investigate the potential limiting steps of peak metabolic rates, we examined gas exchange rates (vdot (O2), vdot (CO2)), respiratory exchange ratio (RER), breathing frequency, tidal volume, minute ventilation volume (V.e) as well as the heart rate, systemic blood flow and stroke volume of Burmese pythons (Python molurus) while fasting at rest, exercising, digesting and exercising while digesting. All measured variables increased significantly during exercise (crawling at 0.4 km h(−)(1) and at vdot (O2max)), highlighted by a 17-fold increase in vdot (CO2) and a 24-fold increase in V.e. During the digestion of a meal equivalent to 25 % of the snake's body mass, pythons responded with increases in vdot (O2) and heart rate similar to those experienced during exercise, along with a 4.5-fold increase in systemic blood flow. Interestingly, pythons hyperventilated while exercising, whereas they hypoventilated during digestion. The combined demands of exercise and digestion resulted in significantly higher vdot (O2), vdot (CO2), breathing frequency and heart rate than during either exercise or digestion alone. Evidently, the capacities of the ventilatory and cardiovascular systems to transport oxygen to locomotor muscles are not a limiting factor in the attainment of peak metabolic rates during exercise in pythons

REFERENCES

    1. Brett, J. R.
    (1972). The metabolic demand for oxygen in fish, particularily salmonids and a comparison with other vertebrates. Respir. Physiol 14, 151–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Longworth, K. E.,
    2. Jones, J. H.,
    3. Bicudo, J. E. P. W.,
    4. Taylor, C. R. and
    5. Weibel, W. R.
    (1989). High rate of O2consumption in exercising foxes: large P Odifference drives diffusion across the lung. Respir. Physiol 77, 263–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Pan, L. G.,
    2. Forster, H. V.,
    3. Bisgard, G. E.,
    4. Dorsey, S. M. and
    5. Busch, M. A.
    (1984). Cardiodynamic variables and ventilation during treadmill exercise in ponies. J. Appl. Physiol 57, 753–.
    OpenUrlAbstract/FREE Full Text
    1. Secor, S. M. and
    2. Diamond, J.
    (1995). Adaptive responses to feeding in Burmese pythons: pay before pumping. J. Exp. Biol 198, 1313–.
    OpenUrlAbstract/FREE Full Text
    1. Seeherman, H. J.,
    2. Taylor, C. R.,
    3. Maloiy, G. M. O. and
    4. Armstrong, R. B.
    (1981). Design of the mammalian respiratory system. II. Measuring maximum aerobic capacity. Respir. Physiol 44, 11–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Segal, K. R. and
    2. Gutin, B.
    (1983). Thermal effects of food and exercise in lean and obese women. Metabolism 32, 581–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Suarez, R. K.
    (1992). Hummingbird flight: Sustaining the highest mass-specific metabolic rates among vertebrates. Experientia 48, 565–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Suarez, R. K.
    (1996). Upper limits to mass-specific metabolic rates. Annu. Rev. Physiol 58, 583–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Taylor, R.,
    2. Maloiy, G. M. O.,
    3. Weibel, E. R.,
    4. Langman, V. A.,
    5. Kamau, J. M. Z.,
    6. Seeherman, H. J. and
    7. Heglund, N. C.
    (1981). Design of the mammalian respiratory system. III. Scaling maximum aerobic capacity to body mass: wild and domestic mammals. Respir. Physiol 44, 25–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Vinegar, A.,
    2. Hutchison, V. H. and
    3. Dowling, H. G.
    (1970). Metabolism, energetics and thermoregulation during brooding of snakes of the genus Python (Reptilia, Boidae). Zoologica 55, 19–.
    OpenUrl
    1. Wagner, P. D.
    (1996). Determinants of maximal oxygen transport and utilization. Annu. Rev. Physiol 58, 21–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Walton, M.,
    2. Jayne, B. C. and
    3. Bennett, A. F.
    (1990). The energetic cost of limbless locomotion. Science 249, 524–.
    OpenUrlAbstract/FREE Full Text
    1. Wang, T.,
    2. Carrier, D. R. and
    3. Hicks, J. W.
    (1997). Ventilation and gas exchange in lizards during treadmill exercise. J. Exp. Biol 200, 2629–.
    OpenUrlAbstract
    1. Welle, S.
    (1984). Metabolic responses to a meal during rest and low-intensity exercise. Am. J. Clin. Nutrit 40, 990–.
    OpenUrlAbstract/FREE Full Text
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Journal Articles
Ventilatory and cardiovascular responses of a python (Python molurus) to exercise and digestion
S.M. Secor, J.W. Hicks, A.F. Bennett
Journal of Experimental Biology 2000 203: 2447-2454;
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