Influence of sustained cognitive loading on finger circulatory and thermoperceptual responsiveness to localized cooling

Our aim was to examine whether finger vasomotor and thermoperceptual responses to local cooling would be modulated by sustained cognitive loading. To this end, finger temperature, circulatory (i.e., cutaneous vascular conductance, CVC) and perceptual responses were monitored, in twelve healthy men, during and after a 30-min hand immersion in 8°C water, performed either immediately after a 60-min continual execution of a cognitive task battery (cognitive→cold trial), or during the simultaneous performance of the cognitive task (cognitive+cold trial). Subjects responses were compared with those obtained in a control cold-provocation trial, wherein they watched an emotionally-neutral documentary. The cognitive task temporary enhanced the perceived levels of mental effort and fatigue in both intervention trials. In the cognitive→cold trial, the cold-induced reduction in finger CVC and increase in mean arterial pressure were blunted (P < 0.01), and the thermal discomfort was alleviated (P = 0.05). In the cognitive+cold trial, no intertrial differences were noted during the cold-water immersion phase (P ≥ 0.28), but the finger CVC was enhanced during the last part of the rewarming phase (P = 0.05). Present findings, therefore, demonstrate that (i) in moderately mentally-fatigued individuals, finger cold-induced vasoconstriction is transiently attenuated, and thermal discomfort is mitigated, and (ii) superimposition of cognitive loading on cold stress does not alter finger vasoreactivity or thermosensitivity during cooling, but facilitates finger reperfusion following cooling.