How Infrared Therapy Works on Circulation

Put a flashlight against your palm in a dark room and you will see red light coming through the other side. Red and near-infrared wavelengths pass through tissue in a way that blue and green light does not, because the main absorbers in your body, water and hemoglobin, happen to absorb relatively little in that particular band. Physicists call it the optical window.

That window is why therapeutic devices cluster in the 600 to 900 nanometer range. The system we use delivers 890 nanometers, near-infrared, invisible to the eye and felt only as gentle warmth.

What absorbs it

Inside nearly every cell are mitochondria, and inside mitochondria sits an enzyme called cytochrome c oxidase. It is the final step in the chain that turns oxygen and nutrients into usable energy. It is also a chromophore, meaning it absorbs light at specific wavelengths, and its absorption peaks fall in the red and near-infrared range.

This is the foundation of what researchers call photobiomodulation. Light is not heating the tissue in any meaningful way and it is not killing anything. It is being absorbed by a specific molecule that then behaves differently.

The nitric oxide step

The mechanism most often proposed for the circulatory effect involves nitric oxide. Nitric oxide can bind to cytochrome c oxidase and occupy the site oxygen would otherwise use. The leading hypothesis is that near-infrared absorption releases that bound nitric oxide back into the surrounding tissue.

That would produce two effects at once. The enzyme is freed to resume normal function, and nitric oxide, which is the body's principal signal for relaxing the smooth muscle in blood vessel walls, is released precisely where the light was applied. Vessels dilate locally and flow increases in that specific area.

Worth being straight about: this is the working model, well supported in laboratory work and widely accepted as the explanation, rather than something directly observed inside a patient's foot during a session.

What a session is like

Flexible pads holding arrays of infrared diodes are placed in direct contact with the skin, typically on the soles of the feet and along the calves, and moved higher on the leg as treatment progresses. Sessions run thirty to forty minutes. There is no sound and no sensation beyond warmth.

Some patients notice tingling or a pulsing feeling in the feet during or after treatment. This is a recognized response as circulation increases in an area that has not had much, and it usually settles as sessions continue.

The device is cleared by the FDA for temporarily increasing local circulation and for temporary relief of pain, stiffness, and muscle spasm. That is what it is for and that is how we use it.

Where it fits in a plan

We do not use infrared as a standalone treatment. It is one component of a program built around measurement, and we test sensory function before and during care so that we and the patient are looking at data rather than impressions.

To find out what is happening in your feet, call (725) 255-7333. Henderson, southwest Las Vegas, and North Las Vegas.