Abstract
AIM: To evaluate whether a sustained period of normobaric O(2) breathing would modulate acral-skin vasoreactivity and thermosensitivity to localised cooling. METHODS: Eight healthy men performed a 30-min normoxic and hyperoxic (100% O(2)) hand cold (8 °C water) provocation, while immersed to the chest either in 35.1 (0.4)°C (normothermic trial) or in 21.0 (0.1)°C (hypothermic trial) water. Finger temperature, circulatory and perceptual responses were monitored. RESULTS: During the normothermic trial, hyperoxia augmented the cold-induced drop in finger temperature, and attenuated the rewarming (P = 0.03). Hyperoxia also enhanced the sensation of pain (P = 0.04). During the hypothermic trial, hyperoxia did not modify finger temperature, circulatory and perceptual responses to cold (P > 0.05). CONCLUSION: In normothermia, hyperoxia aggravates finger cold-induced vasoconstriction and pain sensation. In mild hypothermia, however, any hyperoxia-evoked influence on finger vasomotion and thermonociception is overridden by the generalised vasoconstriction and thermal discomfort instigated by whole-body cooling.