Dose and time-response effect of photobiomodulation therapy on glycemic control in type 2 diabetic patients combined or not with hypoglycemic medicine: a randomized, crossover, double-blind, sham controlled trial.

Photobiomodulation therapy (PBMt) combined or not with oral hypoglycemic medication has not been investigated in type 2 diabetes (T2DM) patients. All ten T2DM patients were assessed randomly at six different occasions (3 with and 3 without regular oral hypoglycemic medication). Capillary glycemia was assessed after overnight fast (pre-prandial), 1h postprandially (standardized meal, 300 kcal), and 30 min, 3h, 6h, 12h post PBMt (830nm; 25 arrays of LEDs, 80mW/array). Three doses (0J - sham, 100J, 240J per site) were applied bilaterally on quadriceps femoris muscles, hamstrings, triceps surae, ventral upper arm and forearm; and randomly combined or not with oral hypoglicemic medication, totaling six different therapies applied for all ten TDM2 patients (PBMt sham, PBMt 100J, PBMt 240J, PBMt sham+medication, PBMt 100J+medication, PBMt 240J+medication). Cardiac autonomic control was assessed by heart rate variability (HRV) indices. Without medication, there was reduction in glycemia after all PBMt doses, with 100J as the best dose that persisted until 12 hours and presented lower area under the curve (AUC). With medication, glycemia decreased similarly among doses. No differences between 100J and sham+medication, but AUC was significantly lower after 100J, suggesting better glycemic control. Low frequency component of HRV increased after sham+medication and 100J, suggesting higher sympathetic activation. PBMt showed time- and dose-response effect to reduce glycemia in T2DM patients. Effects on HRV were consistent with glycemic control. This article is protected by copyright. All rights reserved.