The role of hydration on peripheral response to cold.

Ten met, were dehydrated by restriction of fluid intake and by exercise over 2-1/2 days (weight loss: 4.6%). Body weight returned to -1.6% within 10 hours after rehydration, suggesting the weight loss was fluid loss. Measures of blood and urine constituents also were indicative of dehydration. These subjects experienced a cold test prior to and after dehydration and after rehydration. The fingers, but not the back of the hand, of the dehydration group were significantly colder (P<0.5) following dehydration. A group of 10 control subjects tested under identical conditions, but hydrated at all times, showed no changes. INTRODUCTION The physiological response to peripheral cooling may depend on environmental factors, such as prior cold exposure (1, 2, 3), physical training (4, 5) and hydration state (6, 7). Possible genetic and racial differences have also been reported (8, 9, 10, 11). 00p) Several studies (12, 13, 14, 15) have shown that hypohydration is a problem in cold climates. Men exposed to 14 1ton •or arctic survival conditions In tents with ad libitum water (no GRA&I food) lost 8% of their body weight in 5 days. Based on the 'Mced [] i electrolyte loss, 62% cf this loss was attributed to fluid loss (13). Canadian military operations in cold climates have indicated.that dehydration was a major contributing cause of Qasualties and b 1it, Cor.r ,A"•11 S Olip r Ilj la