Showers at 25 C and below increased ventilation in man and respiration often could not be controlled voluntarily during showers at near 0 C. The increase took place within seconds and was accompanied by an increase in arterial pO2. The response could be obtained from high decerebrate cats and is believed to be a reflex initiated by cold receptors in the skin and mediated at midbrain level. The chest and abdomen were the most sensitive areas in man, but chilling any large area on the trunk or limbs caused some increase in ventilation. Although the showers caused an inspiratory shift in respiration and a sensation of difficulty in breathing, they caused little increase in airway resistance and no decrease in pulmonary compliance. respiration; reflex; cold showers Submitted on May 15, 1964