Acid-Base Characteristics of Steady-State Exercise in Rats Adapted to Simulated Altitude
Acclimation to altitude hypoxia results in adaptive changes which ultimately lead to an improvement in tissue oxygen delivery (for review, see Bouverot, 1985). Some of these adaptations produce changes in systems not directly related to oxygen transport. An example of this are the changes in the acid-base balance that follow prolonged exposure to altitude. The hyperventilation leads to hypocapnia and extra- and intracellular bicarbonate depletion (Freeman and Fenn, 1953, Olson and Dempsey, 1979, Bouverot, 1985, Gonzalez and Clancy, 1986 a,b) which tends to lower the buffer value of extra- and intracellular fluids. On the other hand, the increased hemoglobin concentration associated with hypoxia results in an increase in the non-bicarbonate buffer value of blood (Gonzalez and Clancy, 1986a). These features, coupled with differences in the rate of renal excretion of acid-base equivalents (Widener et al., 1986), modify the responses of hypoxia-adapted animals to challenges in the acid-base balance.
KeywordsBlood Lactate Concentration Lactic Acid Concentration Simulated Altitude Prolonged Hypoxia Hypobaric Chamber
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- Bouverot, P., 1985, Adaptation to Altitude Hypoxia in Vertebrates, Springer Verlag, Berlin.Google Scholar
- Cerretelli, P., 1980, Gas exchange in altitude, in: “Pulmonary Gas Exchange,” J.B. West, ed., Vol. II: Organism and Environment, pp. 97–147, Academic Press, New York.Google Scholar
- Flaim, S.F., Minteer, W.J., Clark, D.P. and Zelis, R., 1979, Cardiovascular response to acute aquatic and treadmill exercise in the untrained rat,J. Appl.. Physiol: Respir. Environm. Exercise Physiol, 46: 302–308.Google Scholar
- Fregosi, R.F. and Dempsey, J.A., 1984, Arterial blood acid-base regulation during exercise in rats,J. Appl. Physiol: Respir. Environm. Exercise Physiol, 57: 396–402.Google Scholar
- Olson, E.B. and Dempsey, J.A., 1978, Rat as a model of humanlike ventilatory adaptation to chronic hypoxia, J. Appl. Physiol.: Respir. Environm. Exercise Physiol., 44: 763–769.Google Scholar
- Otis, A.B., 1964, Quantitative relationships in steady-state gas exchange, in: “Handbook of Physiology,” Section 3: Respiration, Vol. I., W.O. Fenn and H. Rann, ed., pp. 681–698, American Physiological Society, Washington, D.C.Google Scholar
- Wagner, P.D., Sutton, J.R., Reeves, J.T., Cymerman, A., Groves, B.M. and Malconian, M.K., 1987, Operation Everest II: Pulmonary gas exchange during a simulated ascent to Mount Everest,J. Appl. Physiol.: Respir. Environm. Exercise Physiol., 63: 2348–2359.Google Scholar