When must i use cold therapy over heat therapy for back pain?

Yuo could either one: Cold therapy produces vasoconstriction, which slows circulation reducing inflammation, muscle spasm, and pain. Heat therapy induces vasodilation: drawing blood into the target tissues. Increased blood flow delivers needed oxygen and nutrients, and removes cell wastes. The warmth decreases muscle spasm, relaxes tense muscles, relieves pain, and can increase range of motion.