Effects of Combined Far-Infrared Radiation and Acupuncture at ST36 on Peripheral Blood Perfusion and Autonomic Activities

Using four-channel photoplethysmography (PPG) for acquiring peripheral arterial waveforms, this study investigated vascular and autonomic impacts of combined acupuncture-far infrared radiation (FIR) in improving peripheral circulation. Twenty healthy young adults aged 25.5 ± 4.6 were enrolled for 30-minute measurement. Each subject underwent four treatment strategies, including acupuncture at ST36 (Zusanli), pseudoacupuncture, FIR, and combined acupuncture-FIR at different time points. Response was assessed at 5-minute intervals. Area under arterial waveform at baseline was defined as AreaBaseline, whereas AreaStim referred to area at each 5-minute substage during and after treatment. AreaStim/AreaBaseline was compared at different stages and among different strategies. Autonomic activity at different stages was assessed using low-to-high frequency power ratio (LHR). The results demonstrated increased perfusion for each therapeutic strategy from stage 1 to stage 2 (all p < 0.02). Elevated perfusion was noted for all treatment strategies at stage 3 compared to stage 1 except pseudoacupuncture. Increased LHR was noted only in subjects undergoing pseudoacupuncture at stage 3 compared to stage 1 (p = 0.045). Reduced LHR at stage 2 compared to stage 1 was found only in combined treatment group (p = 0.041). In conclusion, the results support clinical benefits of combined acupuncture-FIR treatment in enhancing peripheral perfusion and parasympathetic activity.