Central and peripheral control mechanisms of shivering and its effects on respiration

¹ Department of Physiology, Lovelace Foundation, Albuquerque, New Mexico

Central and peripheral contributions to the initiation of shivering have been studied in anesthetized dogs employing a thermal dissociation technique. Shivering was elicited invariably during differential cooling of the head or the trunk alone as well as in the course of whole-body cooling. Either ‘peripheral’ or ‘central shivering’ could be produced repeatedly and also inhibited by elevation of subcutaneous temperature in central shivering or brain temperature in peripheral shivering. In part 2 of this study, respiratory effects of shivering have been assessed during the steady state of hypothermia in the anesthetized animal. During shivering, O₂ intake and CO₂ output were doubled or tripled but the respiratory exchange ratio remained essentially unchanged. Total ventilation increased linearly with metabolic rate and yet arterial pH, pCO₂ and buffer base revealed no significant changes with or without shivering. Although alveolar ventilation was increased almost three times, no marked alterations occurred in physiological dead space. Moderate hemoconcentration and a consistent elevation of pulse pressure were seen during shivering.