Effect of 660/850 nm LED on the microcirculation of the foot: neurovascular biphasic reflex.

Phototherapy (LED) can be used to stimulate the healing of chronic ulcers of the lower limb, as it affects healing cells and neurons. In this way, this study has sought to know if the heat stimulus of the 660-/850-nm contact LED is sufficient to trigger the response in the peripheral sympathetic nervous system of normal volunteers. The LED was applied on the right foot of forty-two normal volunteers followed by serial infrared images. After the stimulus, a biphasic hyperthermia curve was observed synchronously in both feet, in the right and left halluxes, while hyperthermia was attributed to the redistribution of postural blood flow in the plantar region, which may indicate independent neurovascular mechanisms. Thus, periodic thermographic analysis can be used in the evolution of the LED treatment.