You may want to double bag these to avoid leaks. When to use heat Heat should never be used during the first 48 to 72 hours after an injury. This can increase the circulation to the area too much increasing the swelling and microscopic bleeding causing the injury to worsen and the pain to increase. Heat can be very effective during the subacute and chronic stages on an injury. Heat can effectively decrease pain, promote healing by increasing circulation, help tight muscles or muscle spasms to relax, and prepare stiff joints for movement.
Heat is probably one of the most frequently used methods for home pain management.
Everyone has probably used some form of heat at some point in time to help sore, stiff muscles or joints. The effects of heat do not last as long as cold, but can give temporary relief for up to an hour or more. All of these types can be effective, but it is important to remember that all are considered forms of heat when following the guidelines for using heat appropriately. While heat is probably one of the most widely used home treatments, it is also probably one of the most incorrectly used treatments. This has to be one of my biggest pet peeves as a Physical Therapist.