Immediate Effects of Monochromatic Infrared Energy on Microcirculation in Healthy Subjects

Abstract

The purpose of this study was to evaluate the influence of monochromatic infrared energy (MIRE) on the microcirculation of the skin surface of the feet in healthy subjects. Near-infrared energy was shown to increase microcirculation in an animal study. In humans, only one case study demonstrated that MIRE increases microcirculation in the skin of the lower limbs. Thirty healthy volunteers were recruited and randomly allocated into three groups to receive either: (1) active MIRE; (2) sham MIRE (placebo group); or (3) warm packs (control group) on the feet. The MIRE device comprised an array of 60 x 890 nm LEDs attached to flexible pads (3×7.5 cm). Each diode spot size was 0.2 cm(2), and each LED power was 12 mW with a power density of 60 mW/cm(2). The arrays were placed in direct contact with the skin for 30 min delivering a total fluence of 108 J/cm(2) over an area of 22.5 cm(2). Capillary blood cell velocity (CBV) and superficial skin blood flow (flux) were recorded before and after intervention. Significant differences among the three groups were recorded in both CBV and flux (both p<0.05). Post-hoc comparisons indicated that a significantly greater increase in both CBV and flux occurred in the active MIRE group than in the placebo group and control group (all p<0.05). A 30-min MIRE produced a significantly greater increase in the CBV and flux of the feet in the active MIRE group than in the placebo and control groups.