Effects of immersion of the hand in cold water on digital blood flow

¹ Department of Physiology and Biophysics, University of Kentucky, Lexington, Kentucky

The temperatures of the tip of the middle fingers (T_s) of nine comfortably warm subjects have been recorded during immersion of all the fingers of one hand in a 27-liter bath containing slowly stirred water at temperatures ranging from 4.6 to 40 C (T_w). Blood flow (F = ml/cm² per min) was estimated from the average T_s for the last 15 min of a 20-min period, T_w and body temperature (T_b) by using the equation: F = 1,087 x K(T_s – T_w)/ (T_b – T_s). (K = 0.0134 kcal/cm² per min per °C.) The increase in F per °C reduction in T_w below 10 C was 0.16 ± 0.077 (P < .05). This value gives a measure of the vasodilatation occasioned by immersion in water below 10 C. The sample regression equation of F on T_w was: F = 4.1 – .16 T_w ± 0.17 (n = 27; range of T_w = 4.6 to 10 C). This method of estimating blood flow at several levels of T_w describes more fully the peripheral circulatory response to cold than methods in which only one level of T_w is used.

Submitted on August 28, 1963