Variation in the susceptibility to cold injury in Indians

The peripheral vascular responses during local cold stress, (heat output from the hands and cold induced vasodilatation-CIVD response) were studied on 4 groups (10 each) of Indian population, viz., South-Indians, North-Indians, Gurkhas and High Altitude Natives (HAN) of 3,500m. The parameters were recorded at Delhi, and at 3,500 m in thermoneutral laboratory (25–28°C). The sea level readings of HAN were taken after 3 weeks of their stay at Delhi; and that of lowlanders at 3,500 m were taken after 3 weeks of their sojourn. The results show that the heat output and CIVD were highest in HAN, and lowest in the South-Indians. The responses of the other two groups were similar in nature and were better than that of South-Indians. Based on an earlier study which has shown that individuals with higher heat output and CIVD are better protected against the occurrence of cold injuries, it can be suggested that HAN are most resistant and the South-Indians are highly susceptible to the occurrence of cold injuries.