Heat from sauna use and cold exposure both stimulate norepinephrine release, but the intensity of cold is crucial for triggering significant stress responses. Immersing in cold water at 40°F can boost norepinephrine levels by 200-300%, while longer exposures at 57°F can increase it by 530%. The interplay of hot and cold therapies, particularly their combined effects, remains an area ripe for further exploration, especially regarding safety.
