Evidence of viscerally‐mediated cold‐defence thermoeffector responses in man

Visceral thermoreceptors that modify thermoregulatory responses are widely accepted in animal but not human thermoregulation models. Recently, we have provided evidence of viscerally‐mediated sweating alterations in humans during exercise brought about by warm and cool fluid ingestion. In the present study, we characterize the modification of shivering and whole‐body thermal sensation during cold stress following the administration of a graded thermal stimuli delivered to the stomach via fluid ingestion at 52, 37, 22 and 7°C. Despite no differences in core and skin temperature, fluid ingestion at 52°C rapidly decreased shivering and sensations of cold compared to 37°C, whereas fluid ingestion at 22 and 7°C led to equivalent increases in these responses. Warm and cold fluid ingestion independently modifies cold defence thermoeffector responses, supporting the presence of visceral thermoreceptors in humans. However, the cold‐defence thermoeffector response patterns differed from previously identified hot‐defence thermoeffectors.