Should a sprain be treated with heat or cold therapy?

Whether to apply heat or cold depends entirely on the clinical situation.

1. Cold therapy is primarily for pain relief. In acute injuries—such as ankle sprains, knee twists, muscle strains, or contusions—the onset of pain and swelling is typically immediate. Immediate application of cold therapy provides analgesic and numbing effects. Within the first 24 hours following an ankle sprain—the acute phase of injury—cold therapy is recommended. It reduces local blood flow, inhibits swelling, and alleviates pain. Applying heat during this period would cause vasodilation, increase local blood flow, raise tissue temperature, and thereby exacerbate both pain and swelling. Similarly, topical agents such as alcohol-based rubs, safflower oil, or medicated plasters produce a warming effect; therefore, these should be avoided in the initial phase of injury.

2. Heat therapy promotes healing. After 48 hours post-joint sprain—and provided there is no ongoing bleeding or active swelling—heat therapy may be used to accelerate resolution of edema and relieve pain. Applying moist heat (e.g., warm damp towels, hot water bottles, or warmed hard-boiled eggs) to the affected area elevates local temperature, enhances blood circulation and local metabolism, and facilitates absorption of hematoma and exudate—thereby promoting faster reduction of swelling and wound healing. Additionally, heat therapy improves soft-tissue elasticity, helps prevent joint stiffness and muscle spasm, and further relieves pain.