The Lung and Heart meridians are chosen as two specific studied meridians. 120 participants will be enrolled and divided into the healthy control group, chronic obstructive pulmonary disease (COPD) group and healthy intervention group. Laser doppler flowmetry (LDF) will be used to assess the microcirculatory characteristics of meridian phenomena for the Heart and Lung meridians. The site specificity for the meridian-visceral association will be investigated by comparing the microcirculatory difference between the Heart and Lung meridians in the healthy control group and COPD group. Besides, participants in the healthy intervention group will receive two sessions of moxibustion in the Heart meridian and Lung meridian respectively to explore the site specificity for the surface-surface association.
