How to Use Heat Patches on Sore Muscles. Heat therapy, along with its counterpart ice therapy, has been one of the most effective methods for treating sore muscles. Heat increases blood flow, reduces pain and is relaxing. Heat patches are one of the more popular items on the market today. They are convenient, because they allow you to be mobile while they work. Most heat patches are made of iron, water, carbon and salt. They work by the process of iron oxidation. When iron is exposed to oxygen, it generates heat, soothing sore muscles.
Pick up a heat patch at your local drugstore or order from online retailers Drugstore.com, Shopping.com or NexTag (see Resources below). They carry heat patch brands such as Bengay, Beyond BodiHeat and Icy Hot.
Select a patch that will sufficiently cover the afflicted area. Regular-size patches will cover sore muscles in the arms, legs, neck and a portion of the shoulders. Large or extra large will be used for the entire lower back and upper back, as well as both shoulders and the hips.
Wash and dry the skin in the area where your sore muscles are. Most heat patches will not stick if the skin is wet.
Remove any protective film that is on the heat patch. Once the film is removed, the iron will oxidize, producing heat.
Apply the adhesive side of the patch to your sore muscles. Depending on the brand, it will take between 5 and 15 minutes for your heat patch to start working. Most heat patches will last at least 8 hours, but you may need to remove the patch if it becomes too hot or causes any discomfort.
Use most heat patches no more than once every 24 hours. Some heat patches are reusable, but most provide just a single use.