It is possible to generate enough heat to prevent frostbite in mild freezing conditions for some hours using a Tibetan thermoregulation technique. They practice

It is possible to generate enough heat to prevent frostbite in mild freezing conditions for some hours using a Tibetan thermoregulation technique. They practice this technique in nearly freezing conditions and are required to dry 3 wet soaked towels. It requires much training, patience, and practice to develop this skill. Furthermore, there is a technique to raise the temperature of the extremities as well. https://www.buzzworthy.com/monks-raise-body-temperature/ https://www.buzzworthy.com/monks-raise-body-temperature/ Deliberate shivering of more muscle groups is another idea but unlikely to raise extremity temperatures.