Respiration physiology
-
Respiration physiology · Oct 1983
Comparative StudyEffects of PCO2 on respiratory pattern during thermal and exercise hyperventilation in domestic fowl.
The relationship between respiratory pattern and arterial PCO2 was investigated during hyperventilation induced by graded exercise and hyperthermia. Treadmill exercise was performed both in isothermic and hyperthermic conditions. Isothermic exercise was induced by spraying the birds with water before exercise at environmental temperatures of 18 +/- 2 degrees C. ⋯ When normal PCO2 was maintained during hyperthermic exercise, as a result of the administration of CO2-enriched air, polypnea was suppressed and the tidal volume-respiratory frequency relationship became identical to that observed during graded isothermic exercise. Maintenance of normal PCO2 in resting birds subjected to a gradual increase in environmental temperature also resulted in changes in respiratory pattern identical to those obtained during eucapnic exercise. It is concluded that, provided arterial PCO2 is held constant, the pattern of breathing is the same for hyperventilation induced by exercise or by body temperature increases.