Influence of food intake on cold-induced vasodilatation of finger.

When the finger is immersed in ice water, a sharp fall of the skin temperature is followed by its gradual rise due to the cold-induced vasodilatation (CIVD). The present study was attempted to examine whether the CIVD is affected by a small increase in internal heat load due to dietary thermogenesis. A 10-min immersion of the left middle finger in ice water was performed at room temperature of 25-26 degrees C on 12 female subjects 60 min before, and 30 and 90 min after ingestion of a meal containing 700 kcal. Skin temperature of the finger and O2 consumption were continuously measured before, during, and after the immersion. A CIVD index was measured using the data of the rising phase of skin temperature during the immersion. The CIVD index, a newly developed parameter in the present study, could reflect both the rapidity and the magnitude of CIVD response during the immersion. Compared with pre-prandial values, the O2 consumption and the CIVD index significantly increased by 15 and 69%, respectively, at 30 min and by 15 and 50% at 90 min of the post-prandial period. Esophageal temperature was studied on another 5 subjects (1 male and 4 females) and it rose by 0.27 degrees C during the 90-min post-prandial period. The results, in support of the involvement of the central nervous system control in CIVD, suggest that the central process is so sensitive as to operate in a 15% increase in heat load into the body.