Inclusion Criteria:  Aged 18-79 The blood pressure is normal: systolic blood pressure <140 mmHg, and diastolic blood pressure <90 mmHg The physical examination and electrocardiogram are normal  Exclusion Criteria:  Subjects with carotid intima-media thickness ≥ 1.0 mm should be excluded; Subjects with previous cardiovascular disease history and medication history should be excluded. The main diseases include coronary heart disease, congenital heart disease, heart failure, hypertension, stroke, hyperlipidemia, diabetes, aortic arteritis, etc.; Subjects with past medical history and medication history of endocrine, rheumatism, chronic respiratory disease, liver and kidney disease should be excluded; Obese subjects (BMI ≥ 28 kg/m2), professional athletes, pregnant and lactating women should be excluded; Alcohol or drug addicts and smokers who have not quit smoking should be excluded.