Study subjects included 40 chronic obstructive pulmonary disease (COPD) participants in the COPD group and 40 age-matched healthy participants in the healthy control group. Laser doppler flowmetry, infrared thermography, and functional near-infrared spectroscopy were respectively adopted to measure (1) the perfusion unit (PU), (2) temperature, and (3) regional oxygen saturation (rSO2) of 4 specific somatic sites distributing in the heart and lung meridians. These 3 outcome measures reflected the microcirculatory, thermal and metabolic characteristics of the body surface, respectively.