Heating pads work on the principle of thermotherapy, which involves applying heat to the affected area. Heat increases blood flow, which can help relax tight muscles and soothe stiff joints. This increased circulation not only delivers essential nutrients to the injured area but also aids in the removal of waste products, promoting faster healing. Heat can also alleviate pain by interrupting the pain-spasm cycle. When muscles tighten due to pain, applying heat can help them relax, reducing discomfort.