Use cold to reduce inflammation and limit bleeding (for impacts, sprains), and use heat to relax muscles and improve circulation (for contractures, muscle pain, menstrual cramps).

noli's read

The recommended approach is widely supported by standard care practices. The effect of cold on vasoconstriction and the slowing of cellular metabolism during acute injuries is a clinical consensus, although systematic reviews (e.g., Cochrane Library, 2012) highlight that the quality of evidence regarding the actual effectiveness of cold for reducing long-term pain remains moderate. The use of heat for muscle relaxation and spasm relief is based on improving local blood circulation, which is validated by observational and clinical studies for back pain or menstrual pain. The creator omits, however, that prolonged cold can sometimes delay optimal tissue healing, a point often debated in sports literature. Their practical advice on safety (do not apply directly to the skin) is essential to avoid thermal burns. Overall, the recommendations are balanced and correspond to standard practices for non-pharmacological pain management.

the sources

No named source held this one up — that absence is part of the verdict.