The effect of cold induced vasodilation on skin temperature rewarming, manual dexterity and neuromuscular function

Introduction: This study investigated the effect of cold induced vasodilation during cold water immersion on skin temperature passive rewarming in air and recovery of manual dexterity after immersion.Methods: Ten healthy males completed the study. After baseline measurements in a climatic chamber (25°C, 40% relative humidity), they cooled their forearm in 8°C water for 20 min, and then rewarmed in air for 30 min. They completed the protocol on two separate occasions (days) with different manual dexterity tests. In one condition,participants inserted a pin into a hole as many times as possible in 30 sec (Per due pegboard). In another condition, they controlled force output during a sine-wave tracking task by extending their index finger against a force plate (visuomotor tracking). Thedexterity tests were performed at baseline and repeated every 4 min during rewarming.Middle finger skin temperature (Tfinger) was measured continuously during the experiment. Electromyogram (EMG) was measured using surface electrode on the first dorsal interosseous (FDI) during the performance test.Results: Both dexterity performance tasks were impaired by the cold-water immersion,and then gradually recovered with skin temperature rewarming. Based on the mean value for 10 participants, there was significant correlation between Tfinger and Perduepeg board and visuomotor tracking performances (r=0.85, r=-0.50, respectively). The mean power frequencies of the EMG in the FDI were significantly lowered after immersion, and gradually recovered during rewarming and associated with the visuomotor tracking performance (r=-0.60). Individual Tfinger averaged during 5-20 minimmersion, an index of cold induced vasodilation (CIVD), was positively correlated with rewarmed Tfinger 17 min after immersion (r=0.76) and visuomotor tracking performance(r=-0.74).Conclusions: The results indicated that individuals who had greater CIVD responses howed faster rewarming in their skin temperature and recovery of manual dexterity performance.