Over the last decade, e-cigarettes have become increasingly popular, due to their promotion as a healthy alternative to traditional tobacco cigarettes. However, there are large discrepancies of knowledge in understanding how these e-cigarettes affect the user's health. The overall goal of this study is to evaluate the impact of e-cigarettes usage on user's cardiopulmonary health

Inclusion Criteria:

E-Cigarette group:

• 21 years of age or older
• Used e-cigarettes (≥3 times/week for ≥3 months)

Non e-cigarette group

● 21 years of age or older

Exclusion Criteria:

• 20 years old and younger
• Use of cigarettes for 15 days or more in the past 60 days
• Use of other tobacco products (cigars, hookah, smokeless) weekly or more frequently in the past 60 days
• Use of marijuana or any illicit or prescription drugs for non-medical use weekly or more frequently in the past 60 days
• Known allergy to propylene glycol or vegetable glycerin
• Evidence of cardiovascular, pulmonary, renal, hepatic, metabolic, or cerebral diseases
• Disorder or use of medication that affects cardiopulmonary health
• Evidence of pregnancy or current nursing