"Appropriate changes in skin blood flow and sweat rate are critical for humans to regulate internal temperature, especially during heat or cold stress. Limited previous research suggests that reductions in oxygen (hypoxia) and elevations in carbon dioxide (hypercapnia) concentrations affect skin blood flow and sweat rate. Up to now, however, the effects of hypoxia and hypercapnia on skin blood flow and sweating during heat or cold stress have not been thoroughly examined and are largely unknown. Research suggests that hypoxia and hypercapnia cause subtle elevations in skin blood flow and sweat rate but it is unknown if hypoxia or hypercapnia alters critical skin blood flow and/or sweat rate elevations during heat stress. Therefore, specific aims #1 and #2 of this project are to examine the effect of hypoxia and hypercapnia, respectively, on skin blood flow and sweat rate responses to whole body heating. Lower internal temperatures are evident during cold stress and hypercapnia or hypoxia, suggesting that hypoxia and hypercapnia could impair vital decreases in skin blood flow required to conserve heat during cold stress. Therefore, specific aim #3 of this project is to examine the effect of hypoxia and hypercapnia on the skin blood flow response to whole body cooling. These aims will be achieved using the latest and previously acquired research techniques, to gain further insight into thermoregulatory function by assessing skin blood flow/sweat rate and body temperature relationships during whole body heating and cooling under normal, hypoxic and hypercapnic conditions. This award will allow the effective reintegration of an ambitious researcher back into the EU by significantly improving their research environment, providing key foundations for career development and allowing the transfer of significant skills to the U.K and across Europe. Furthermore, the proposed work will enhance European scientific excellence and the world-wide recognition of European science."