Author/Editor		Passias, Thanasis C; Meneilly, Graydon S; Mekjavić, Igor B
Title		Effect of hypoglycemia on thermoregulatory responses
Type		članek
Source		J Appl Physiol
Vol. and No.		Letnik 80, št. 3
Publication year		1996
Volume		str. 1021-32
Language		eng
Abstract		The effects of hypoglycemia on sweating, skin blood perfusion, and shivering responses were investigated in 10 healthy male volunteers. They exercised on an underwater cycle ergometer while immersed to the neck in 28 degrees C water for 20 min at 50% of their maximal work rate. The exercise-induced elevation in esophageal temperature (T(es)) initiated the sweating response (Esw) and increased skin blood perfusion (SkBP) as measured at the forehead. In the 99-min postexercise immersion period, the values of T es relative to resting level (delta T(es)) at which Esw abated, SkBP reached preexercise values, and shivering commenced were defined as the delta T(es) thresholds for cessation of sweating, passive vasodilation, and onset of shivering, respectively. Two trials were conducted 1 wk apart. The subject was hypoglycemic in one trial and euglycemic in the other (plasma glucose was maintained at 2.8 and 5 mM, respectively) with the use of the hyperinsulinemic (insulin infusion rate = 60 mU.m-2.min-1) glucose-clamp technique. Oxygen uptake, Esw, T(es), mean skin temperature, heat flux from the skin, and SkBP were recorded at minute intervals. Although heat flux and SkBP attained significantly higher end-exercise levels during euglycemia, the responses were similar during the postexercise cooling period. Hypoglycemia did not affect the Esw response during the exercise and cooling periods. Whereas the exercise delta T(es) response was unaffected by hypoglycemia, the decrease in T(es) was greater (P < or = 0.005) during the hypoglycemic than during the euglycemic condition. Hypoglycemia did not alter the delta T(es) threshold for cessation of sweating and passive vasodilation but reduced (P < or = 0.001) the delta T(es) threshold for onset of shivering (from -0.09 +/- 0.07 degrees C in the euglycemic condition to -0.65 +/- 0.12 degrees C in the hypoglycemic condition). (Abstract truncated at 2000 characters).
Descriptors		BLOOD GLUCOSE BODY TEMPERATURE BODY TEMPERATURE REGULATION HYPOGLYCEMIA SKIN ADULT EXERCISE HYPOTHERMIA INSULIN TIME FACTORS