Valentine’s Day is near, and you’ll soon be surrounded by colorful hearts in shades of pink and red. But where does the symbol come from? Some experts think it was inspired by the shape of fig or ivy leaves, which were associated with love. Others say it’s from when people thought our hearts had two chambers—instead of the four we know of today.
Whatever the symbol’s origin, the heart inside your body does amazing things. It’s a powerful muscular organ at the core of the circulatory system. It has four chambers, which are hollow spaces that expand and contract to pump blood throughout your body. Over the course of a person’s lifetime, their heart can beat up to 2.5 billion times!
Our heartbeats are guided by electrical pulses. Thousands of times each day, electrical signals travel through your heart. These signals tell the chambers to pump—all while adapting to your body’s needs. Those needs can change quickly too. When resting, an adult heart pumps about 5 liters of blood every minute, but that can jump to 20 liters per minute when exercising. It also works hard: Your heart pumps enough blood every year to fill an Olympic swimming pool. That’s impressive for an organ that weighs less than a can of soda!