sentences:  Reported injuries range from frostbite to severe tissue damage resulting in amputation.Studies have shown that the body activates the hunting reaction after only 10 minutes of cryotherapy, at temperatures less than 49 °F (9.5 °C).The hunting response is a cycle of vasoconstriction (decreased blood flow), then vasodilation (increased blood flow) that increases the delivery of oxygen and nutrient rich blood to the tissue.