There is increasing evidence that hyperthermia can occur in cool climates because of overwrapping and that this practice precedes many deaths labelled as SIDS. We have attempted to test the hypothesis that the interaction of a cold face and a hot body might lead to further hyperthermia in a piglet model. Twelve non-sedated newborn piglets were studied over the first 10 days of development. Oxygen consumption was measured continuously during sleep. Animals were exposed to cold face conditions initially while the animal's body was kept warm and then while the body was hyperthermic. The results show that stimulation of the face with cool ambient air during conditions of raised metabolic activity (hot body) causes a fall in oxygen consumption towards basal levels. These studies do not, therefore, support the hypothesis that a further increase in metabolic rate occurs during combined cold face and hot body exposure in the piglet model.