¹ Planetsmiles Pty Ltd

Photobiomodulation (PBM) is increasingly discussed across dentistry, orofacial pain, rehabilitation, wound care, and other translational clinical settings. Current PBM literature appropriately emphasizes optical parameters, tissue optics, mitochondrial and redox signaling, in flammatory modulation, and local clinical outcomes [1-3]. These foundations remain essential. A complementary question remains less developed: what occurs at the level of the patient during PBM care?

Two patients may receive similar wavelengths, irradiance, fluence, anatomical targeting, and exposure duration. They may still differ in breathing rhythm, muscular guarding, cardiovascular variability, movement, and behavioral regulation during the same clinical encounter. This Perspective proposes that PBM research may benefit from a real-time physiological observation layer at the patient level. The article presents a restrained framework for observing short term heart rate variability (HRV), respiratory rhythm, respiratory heart rate variability patterns, waveform quality, movement, posture, and behavioral context before, during, and after PBM exposure.

The discussion emphasizes biphasic dose-response behavior, hormesis, nonlinear adaptation, and interindividual physiological variability. HRV is not presented as an exposure-selection tool, diagnostic method, treatment endpoint, or proof of effectiveness. Instead, patient-level monitor ing is framed as a complementary observational layer that may help contextualize tissue-level outcomes and patient-reported responses.

Respiratory confounding, LF/HF limitations, placebo and context effects, wearable-device constraints, and the need for ethics-approved prospective studies remain central. If investigated carefully, this framework may help PBM research describe dynamic treatment-response patterns within a broader systems-physiology context.