THE EFFECTS OF NICOTINE ON THE THERMOREGULATORY RESPONSES DURING ACUTE COLD EXPOSURE

Abstract

The purpose of this study was to examine the effects of nicotine (NIC) on the thermoregulatory responses during acute cold exposure. Six males and six females between the ages of 19 and 25 years participated in this study. All subjects were active, apparently healthy smokers. Each subject performed two cold air trials (CATs) consisting of a 30 minute baseline period (BASE) and a 120 minute exposure to 10°C air. One CAT was performed following a NIC dosing using a 21 mg transdermal patch while the other trial was performed after a placebo (PL) treatment. During the CATs, there were no differences in rectal temperature (TRE) or mean skin temperature between the PL and NIC treatments compared to the PL treatments in either sex (P > 0.05). However, in males, heat production was 12% lower (P < 0.05) and tissue insulation was 17% higher (P < 0.05) during the NIC treatment compared to the PL treatment, while these responses in females were unaffected. In both males and females, finger skin blood flow, expressed as a percentage of the BASE value, was higher during the NIC treatment compared to the PL treatment during the CATs (NIC: −76.5%, PL: −87.3%). Lastly, throughout the CATs, there was no difference in thermal sensation between the PL and NIC treatments (P < 0.05). In conclusion, although NIC administration resulted in sex specific alterations in selected thermoregulatory responses during cold exposure, the response in TRE was unaffected. Supported by the Wilderness Medical Society.