Abstract
This paper reviewed in short neural and humoral factors which might be responsible for inducing exercise hyperpnea. As one of the neural factors afferent signals which arise in the exercising limbs and are transmitted via group 111 or IV high threshold sensory fibres were involved. The other neural factor is command signals originating in the central nervous system and being fed onto the respiratory center. Hypothalamic locomotor region is assumed to be a possible locus to integrate these peripheral and central neural signals. There are enough evidences to believe that humoral factors medlated via cardiac output is also essential for the hyperpnea. Changes in CO2 is well correlated with those of the in dynamic as well as in steady-state response. Oscillations in PaCO2 Can be assumed to play a role to link metabolic CO2 changes to those in ventilation. Thus, no single factor can explain the whole process of exercise hyperpnea. Poon's optimization model may give a key to integrate complicated and coflicting experimental resuits in a unique concept.
