The Difference in the Biological Characteristic Characteristics of the Heart and Lung Meridians

Inclusion Criteria: * COPD participants were eligible if they 1) satisfied the diagnostic criteria of COPD; 2) were in the stable phase of COPD; 3) were 20 ≤ age ≤ 75 years; 4) fully understood the study protocol and signed the written informed consent. Healthy participants were eligible if they 1) were healthy subjects who provided a medical examination report within 6 preceding months for confirming their health conditions; 2) were age-matched with the COPD group; 3) fully understood the study protocol and signed the written informed consent. Exclusion Criteria: * COPD patients were excluded if they 1) had other major lung diseases, such as bronchiectasis, pneumothorax, and lung tumors; 2) had concomitant heart diseases; 3) had serious concomitant diseases in major systems that were not controlled effectively 4) had mental diseases, history of drug abuse, and alcohol dependence; 5) were lactating or pregnant and 6)had scarring, hyperpigmentation, redness, swelling and heat in the skin around the measurement sites, which would affect the accuracy of examinations. Healthy subjects were excluded if they 1) had mental illness, history of drug abuse and alcohol dependence; 2) were lactating or pregnant; 3) had scarring, hyperpigmentation, redness, swelling, and heat in the skin around the measurement sites, which would affect the accuracy of examinations.