Acute Effects of Cold Exposure on Cardiovascular System

Inclusion Criteria: * Living in Shanghai during the study period; * Body mass index \> 18.5 and ≤ 28; * Right-handed; * Receiving or having received higher education; * With the ability to read and understand Chinese smoothly. Exclusion Criteria: * Smoking and alcohol abuse; * Current drug and dietary supplements intake; * Subjects with allergic diseases, such as allergic rhinitis, allergic asthma, and atopy; * Subjects with cardiovascular diseases, such as congenital heart disease, pulmonary heart disease, and hypertension; * Subjects with respiratory diseases, such as asthma, chronic bronchitis, and chronic obstructive pulmonary disease; * Subjects with chronic diseases, such as diabetes, chronic hepatitis, and kidney disease; * Subjects who have a history of major surgery due to cardiovascular, cerebrovascular, respiratory, or neurological diseases; * Subjects with neurologic disorders, such as stroke, traumatic brain injury, epilepsy, and schizophrenia; * Abnormal spirometry (FEV1 and FVC ≤ 75% of predicted and FEV1/FVC ≤ 0.65); * Subjects with color vision disabilities.