Local cold acclimation of the hand impairs thermal responses of the finger without improving hand neuromuscular function.

摘要

AIM: To investigate the effects of cold acclimation on the thermal response and neuromuscular function of the hand. METHODS: Ten healthy subjects [three female, seven male, age (mean +/- SD): 27.9 +/- 7.9 years] immersed their right hand in 8 degrees C water for 30 min, 5 days a week for 3 weeks. On the first and the last day, neuromuscular function of the first dorsal interosseus (FDI) muscle was tested. RESULTS: There was no significant change in maximal voluntary contraction strength or evoked contractile characteristics of the FDI after cold acclimation. Minimum finger temperature decreased significantly from 10.6 +/- 1.2 to 9.3 +/- 0.8 degrees C after 3 weeks (P < 0.01), with most of the decrease occurring after a single exposure. Mean finger temperature dropped significantly from 14.2 +/- 1.9 to 11.7 +/- 1.4 degrees C following cold acclimation (P < 0.05), with 90% of this adaptation occurring after 5 days. Onset time of cold-induced vasodilatation increased from 446 +/- 171 to 736 +/- 384 s (P <0.05) and the amplitude decreased from 5.3 +/- 3.2 to 2.5 +/- 2.1 degrees C (P < 0.05). This was significantly different from the control group, who immersed their right hand on the first and last days only. CONCLUSION: These data suggest that cold acclimation does not enhance hand temperature or function but may put the hands at a greater risk of cold injury when exposed to the cold.