By Dr. Priyom Bose, Ph.D. Reviewed by Lauren Hardaker Jun 30 2026 Young adult e-cigarette users with obesity worked harder to breathe during exercise and showed subtle changes in lung mechanics, suggesting that exercise testing may reveal respiratory effects that routine lung function tests can miss.  Study: Respiratory symptoms and exercise responses among adult E-cigarette users with and without obesity. Image credit: Aliaksandr Barouski/Shutterstock.com A recent  Physiological Reports study