Peripheral Cold Tolerance of North Korean Defectors: Cold-Induced Vasodilation in the Fingers of the Arduous March and Jangmadang Generations

This study investigated cold-induced vasodilation (CIVD) responses in the fingers of North Korean defectors, focusing on generational differences between the Jangmadang (JMD) and Arduous March generations (AMG).Twenty-four subjects (14 males, 10 females; 14 JMD, 10 AMG) participated in a 60-min trial, which consisted of 10-min rest, 30-min cold water immersion at 4.0 0.1C, and 20-min recovery.CIVD parameters including minimum finger temperature (T min ), onset time (t onset ), maximum finger temperature (T max ), mean finger temperature (T mean ), amplitude, frequency, and resistance index of frostbite (RIF) were analyzed.AMG showed significantly higher T max compared to JMD (14.2 vs. 11.9C,P = 0.049), while other CIVD parameters showed no significant differences.Notably, all subjects achieved the maximum RIF score of 9 points, indicating superior local cold tolerance compared to general population norms (5-6 points).Body mass index, body weight, and waist circumference showed significant positive correlations with T min (r = 0.574, 0.420, and 0.566, respectively) and negative correlations with t onset .AMG reported significantly lower finger cold sensation at 50 min (P = 0.008).These findings suggest that both generations possess exceptional peripheral cold tolerance, with AMG demonstrating enhanced vasodilatory capacity, likely attributable to prolonged cold exposure during formative years.This study provides foundational evidence for understanding human cold adaptation mechanisms under extreme environmental conditions.