What's Better for Sore Muscles: Ice or Heat?

If you’re not sure whether to apply ice or heat to sore muscles, you know just as much as the experts.

Ice on Left Knee Joint
Jan-Otto / Getty

To heat or ice? It’s a question every beat-up athlete and lifter encounters. But it turns out that the answer to that query isn’t as cut and dry as most would hope. In fact, according to Gary Diffee, Ph.D., professor of kinesiology at the University of Wisconsin-Madison, “in many cases, the answer is, we don’t know.”

That’s because there’s a plethora of underlying causes for muscle stiffness, soreness, and pain. So the right choice between heat (which bolsters blood flow) and cold (which reduces blood flow and swelling) depends. “For example, if muscle stiffness or tightness is the cause of pain or discomfort, then heat will be a good way of loosening those muscles and alleviating the pain,” says Diffee. “But if inflammation is causing the pain, then heat will just make it worse.”

What do the studies say? Most conclude that heat and ice ultimately have a minor effect on muscle pain and recovery from muscle soreness, so which one you use is really up to you. Some studies show that alternating a hot bath (three to four minutes) with 30 to 60 seconds in a cold bath can give you the best of both worlds—expansion of blood vessels followed by closing of blood vessels—to stimulate blood flow and lessen swelling.

Overall, though, the protocol is safe, so whatever ultimately makes your muscles feel a little better is fine. Just don’t leave an ice pack or heat pack directly on the skin for more than 20 minutes at a time or you’ll risk burning or damaging your skin.

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