One and a Half Billion Heartbeats

Many years ago, astronaut-legend Neil Armstrong sat down for an interview with news-legend Walter Cronkite. It was just after the time of the Apollo project, which was coincident with the beginning of the jogging craze.

Cronkite asked Armstrong for his opinion on jogging. Armstrong thought about it for a second, then responded:

"I believe that the Good Lord gave us a finite number of heartbeats and I'm damned if I'm going to use up mine running up and down a street."

This quote has always tickled me. I repeat it whenever anyone asks me to work up a sweat. So I was pleased yesterday, when Geoffrey West, a Santa Fee-based scientist, confirmed what for me has been merely Neil's opinion for the past thirty years.

Interviewed on NPR, West confirmed that the results of his most recent research show the heart of the average mammal, humans included, beats approximately one and a half billion times in its lifetime, regardless of the size of the mammal or its habitat.

In other words, it appears that it doesn't matter if you're an elephant or a mouse. Every mammalian heart is programmed to beat 1.5 billion times - before beating no more.

The story contained a number of nice audio props, such as recordings of the bongo-like heart of a shrew, which beats approximately 1,000 times a minute, and of the whale, whose heart beats (if a low squishy sound can be called a "beat") approximately once every three to four seconds.

But the thing that interested me most was the part the story left out - a quote from one of the most famous humans to yet walk the Earth, which at the time was just his opinion, but which now ranks as a fully-fledged - and very welcome - hypothesis.