Far infrared therapy improves the vascular function of lower extremities in hemodialysis patients

Hemodialysis (HD) patients commonly experience peripheral vascular dysfunction due to multiple risk factors for stenosis. Far infrared radiation (FIR) causes vasodilation and enhances the circulation of vascular access. The effect of FIR on the peripheral vascular system remains uncertain. The study enrolled 28 chronic HD patients from a medical center in 2022. These patients received FIR therapy on both feet for 40 min during each HD session for one year. Ankle-brachial index (ABI), pulse volume record (PVR), skin perfusion pressure (SPP), peripheral vascular sonography (PVS), and maximal venous outflow/segmental venous capacitance were analyzed using paired t-tests and Wilcoxon signed-rank tests to assess changes before and after FIR therapy. FIR significantly reduced the proportion of HD patients with an ABI <0.9 from 7.1 % to 3.6 %. FIR significantly decreased the proportion from 32.1 % to 17.9 % of those with right anterior tibial stenosis on PVS, and the proportion from 53.6 % to 32.1 % of those with arterial stenosis by PVR over the left thigh, especially in those with DM. FIR significantly augmented left plantar SPP of HD patients (from 80.04 mmHg to 94.14 mmHg) and those without DM (from 73.00 mmHg to 95.86 mmHg). FIR significantly reduced the ratio of HD patients with abnormal venous return during respiration in the left common femoral vein (CFV) from 25.9 % to 3.7 %, and of those without DM from 28.6 % to 0 % on bilateral CFV. FIR therapy was associated with improvements in arterial stenosis, skin perfusion, and venous return in the lower extremities.