It’s so close to Valentine’s Day, so we thought we’d talk about the real inspiration behind the symbol of the holiday.

Where is it?

Put your hand on your heart like you’re saying the Pledge of Allegiance. (We’ll wait.) Did you cross your right hand all the way over to the left side of your chest? Probably. But that’s not where the heart is. It’s almost precisely in the middle of the chest, between the lungs. The bottom portion of the heart leans to the left, so the heartbeat feels more prominent on your left side…leading to the belief that the whole organ resides there.

A compact machine

It’s a relatively compact machine — an adult’s weighs about 11 ounces, and it’s about the size of your fist — but it pumps about 2,000 gallons of blood each day at a distance of 60,000 vascular miles.

The heart’s energy

That’s enough energy generated each to a drive a car about 20 miles. (You could power your commute!)

Why the stethoscope?

The stethoscope is a ubiquitous medical tool, always draped around a doctor’s neck so as to listen to a patient’s heartbeat. It was invented by French doctor Rene Laennec in the early 19th century because he didn’t think it was very professional to listen to female patients’ hearts the way other doctors did: by placing their ear directly on the chest.

The heart’s power

The heart pumps the blood that goes to all the other parts of the body to make them work, but only five percent of the body’s blood supply is needed to power the heart itself.

Women vs. men

Women’s hearts beat ever so faster than men’s hearts beat.

Bump-bump

What causes the distinctive “bump-bump” of the heartbeat? The four valves of the organ closing almost all at once.

Ancient heart wisdom

Ancient Greeks thought that human knowledge resided in the left side of the heart. Ancient Egyptians thought the heart moved around the inside of the body as it pleased.

Heart stress

Work is stressful: Heart attacks occur on Monday mornings more than any other time of the week. (They’re also more common on Christmas, Boxing Day, and New Year’s day.)

Heart cancer

On the other side of that, heart cancer is very rare. That disease is caused by an abnormality in cell division, and since heart cells stop dividing, there’s less chance for cancer to occur.