Reproducibility of Photobiomodulation Induced Changes in Local Skin Blood Flow in Healthy Subjects

Norwegian University of Science and Technology16 enrolled

Overview

This study investigated whether near-infrared photobiomodulation (PBM), a non-invasive light therapy, can consistently increase blood flow in the skin of healthy adults. Participants attended two identical study sessions in which they received both active PBM treatment and a placebo treatment using the same device with the light turned off. A subgroup of participants also completed a heat-control session to determine whether any changes in blood flow were caused by the light itself or by heat from the device.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

OTHER

Masking

SINGLE

Enrollment

Conditions

Local Skin Blood Flow

Interventions

Near-infrared photobiomodulation (NIR PBM)DEVICE

Near-infrared photobiomodulation delivered using a modified Anodyne® Therapy System (Model 120). Device parameters included 890 nm wavelength, irradiance of 5.1 mW/cm², radiant exposure of 4.6 J/cm² and total radiant energy of 35.9 J. The intervention consisted of ten cycles of 3 minutes ON followed by 2-minute OFF intervals.

Sham PlaceboDEVICE

Identical device placement and treatment schedule with the LEDs deactivated. No near-infrared light was delivered.

Control (heat)DEVICE

The modified device was wrapped in aluminium foil to prevent near-infrared light from reaching the skin while allowing conductive heat transfer. The protocol was otherwise identical to the active intervention.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 50 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Healthy adults aged 18 to 50 years. * In good general health. * No reported illness during the 3 months preceding enrollment. * Able and willing to provide written informed consent. Exclusion Criteria: * Pregnancy. * Clinically unstable chronic disease. * Chronic dermatological conditions. * Any medical condition that, in the opinion of the study physician, would make participation unsafe or interfere with study procedures.

Locations (1)

NTNU, St Olavs Hospital

Trondheim, Norway

Outcomes

Primary Outcomes

Reproducibility of NIR-induced change in local skin blood flow between two experimental sessions

Local skin blood flow was measured using laser Doppler flowmetry and expressed as blood perfusion units (BPU). A 5-minute baseline measurement was obtained before exposure. This was followed by ten consecutive 5-minute cycles, consisting of 3 minutes of near-infrared (NIR) exposure followed by 2 minutes without NIR exposure, during which skin blood flow was recorded. After completion of the tenth cycle (50 minutes), NIR exposure was discontinued and skin blood flow was recorded for an additional 15 minutes to assess if the blood flow response lasts post NIR exposure. The outcome was expressed as percent change in skin blood flow relative to baseline. Reproducibility was assessed by comparing the percent change from baseline between the two experimental sessions following the same protocol (Day1 Vs Day2).

Time frame: Day 1 and Day 2 (5-minute baseline, 50-minute NIR intervention period, and 15-minute post-intervention assessment).

Secondary Outcomes

change in local skin temperature relative to baseline.

Local skin temperature was measured at the intervention site before the start of the intervention and immediately after completion of the 50-minute intervention period. The change in local skin temperature was calculated relative to the baseline measurement. Measurements were performed using the same protocol on Day 1 and Day 2.

Time frame: Day 1 and Day 2 (baseline and immediately after the 50-minute intervention period).

Data from ClinicalTrials.gov

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