Cardiovascular refers to your heart and blood vessels working together as a system. Your cardiovascular system is like your body's delivery network: your heart pumps blood through thousands of miles of blood vessels, carrying oxygen and nutrients to every cell.

When doctors talk about cardiovascular health, they mean how well your heart and blood vessels are functioning. Cardiovascular exercise (also called cardio) is any activity that makes your heart beat faster and your breathing quicken: running, swimming, biking, or even dancing. These activities strengthen your heart muscle, just like doing push-ups strengthens your arms.

You might hear about cardiovascular disease, which refers to problems with the heart or blood vessels. This is why doctors encourage people to exercise regularly, eat nutritious foods, and avoid smoking: these choices help keep the cardiovascular system strong and healthy throughout life.

Think of your cardiovascular system as a city's water system, with the heart as the central pumping station and blood vessels as the pipes delivering essential supplies everywhere they're needed.