Infrared Radiation Therapy Overview

Infrared Radiation Therapy (IR)

• Superficial thermal agent applied to treat pain and stiffness, increase joint motion, and enhance healing of soft tissue lesions and skin conditions.
• IR is a form of electromagnetic radiation that produces heat when absorbed by matter.
• Sources of IR can be natural (e.g., the sun) or artificial (e.g., radiant heaters).

Infrared Physical Characteristics

• IR is classified into three bands based on wavelength and penetration depth: IRA (short/near IR), IRB (long/far IR), and IRC (not used therapeutically).
• IRA penetrates up to 5 mm into the dermis, while IRB penetrates up to 1 mm into the epidermis.
• The wavelength of IR emitted depends on the temperature of the material.

Sources of Infrared

• Artificial sources of IR include luminous (e.g., electric light bulbs) and non-luminous sources (e.g., moist heat packs).
• Luminous sources emit IRA, visible light, and ultraviolet radiation.
• Non-luminous sources emit primarily IRB radiation.

Physiological effects of Infrared

• Cutaneous vasodilatation: IR leads to vasodilatation due to histamine release and axon reflex mechanisms, causing increased blood flow in the cutaneous circulation.
• Increased metabolism: IR elevates the temperature of superficial tissues, leading to increased metabolic activity which improves cell function and healing.
• Neurological effects: IR can relieve pain by stimulating sensory nerves (A-beta nerve fibers), inhibiting pain at the spinal cord level, decreasing muscle spindle activity for muscle relaxation, removing waste products through improved circulation, and increasing venous return.
• Connective tissue effects: IR increases the extensibility of connective tissue, making it beneficial for improving range of motion (ROM) in conjunction with stretching and mobilization exercises.

IR Indications

• Pain
• Muscle spasm
• Incisional wounds (accelerates healing)
• Subacute and chronic musculoskeletal inflammation
• Chronic mild to moderate edema
• Prior to stretching and mobilizing exercises
• Some skin conditions (e.g., fungal infection)

IR Contraindications

• Acute inflammation
• Acute infection
• Open wounds
• Impaired sensation
• Impaired circulation
• Over the pregnant uterus
• Eyes
• Metal

IR Hazards and Dangers

• Burns: High temperature IR can cause burns, particularly if the patient is unaware of the heat level or unable to communicate.
• Eye damage: The eyes should be protected during IR therapy to prevent dryness or irritation.
• Lowered blood pressure: IR can cause a decrease in blood pressure.