Electric scooters have literally popped up overnight in many cities across the U.S. Leigh Vinocur, MD, an emergency physician in Baltimore, talks about the safety risks that come with this zippy new mode of travel. Flu season starts up soon. We’ll tell you everything you want to know about the shot, including why it can't give you the flu. Also, get the truth about aspirin and your health and learn how to shrug your way to better posture. Check out our slideshow to learn about other numbers that affect your health: Numbers That Matter as Much as Your Weight