Which symptom is typically decreased by thermotherapy?

• A. Subacute edema
• B. Pain
• C. Infection
• D. Increased ROM

Answer: (B)

Thermotherapy primarily reduces pain by relaxing muscles, improving local blood flow, and modulating nociceptive input through warm receptors. Warming tissue helps decrease muscle spasm and stiffness, which lowers the sensation of pain, and it can also alter pain signaling enough to raise the pain threshold. This analgesic effect is the most consistent and direct outcome of heat therapy in many musculoskeletal conditions.

Subacute edema tends to respond less to heat and can even be worsened by increased blood flow and fluid accumulation. Infections are not typically alleviated by heat; active infection is a situation where heat is used with caution or avoided. Increased ROM can occur with heating because tissues become more extensible, but that is a change in function, not a symptom; the question asks which symptom is decreased, and pain fits that description best.