Chukuka S. Enwemeka, PhD, FACSM

Professor and Dean, School of Health Professions, Behavioral and Life Sciences, New York Institute of Technology, New York.

Over the years, our laboratory and those of others have explored the mechanisms underlying the experimentally and clinically observed benefits derived from laser phototherapy. This presentation summarizes our findings and those of others, and they indicate that: (1) The therapeutic effects of light depend heavily on wavelength and dose. Wavelengths in the range of 600 – 1000 nm have been documented to relieve pain and promote tissue repair. (2) Coherence does not seem to play a significant role in this regard given the evidence that—all things being equal—LEDs, SLDs, polychromatic light and lasers yield similar results. (3) Cells transform light energy into ATP using a repertoire of enzymatic, signal transduction and related metabolic activities, including mitochondrial electron transfer. In this regard, cells mimic plants in that they combine the energy from light with those derived from organic matter to power needed metabolic activities. (4) The ATP derived from light energy is used to promote needed metabolic activities, including DNA synthesis, enzyme synthesis, protein synthesis, and the release of mediators including hormones, nitric oxide, and other agents needed to promote tissue repair and/or pain relief; yielding homeostasis. (5) Phototherapy modulates the levels of prostaglandins, somatosensory evoked potentials and nerve conduction velocity; thereby producing pain relief. (6) Similarly, treatment with light produces pain relief by inducing the release of endorphins and by exerting direct effects on cells that mediate inflammation. The experimental and theoretical evidence supporting these findings will be presented and discussed.