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Tuesday, September 4

A billion and a half heart beats

That's all we get in this lifetime, according to three scientists at the Santa Fe Institute in northern New Mexico.

This is just about the coolest NPR segment I have listened to. They really did a fabulous job explaining. Have a listen, it's not too long: Size Matters: The Hidden Mathematics of Life

From the link:
The reason an elephant lives longer than a shrew is not because its heart beats longer. It's because its heart beats slower. So it takes a few more years for the elephant to complete his or her up to one and a half billion beats.

Now comes the subtler question: Why do big things use up energy more slowly?

Nature goes easy on larger creatures so they don't wear out too quickly.

After all, an elephant has trillions more cells than a shrew and they all have to connect and communicate and distribute energy and keep the animal going. In a little animal, the job is easier. In a big animal, there are so many more blood vessels, moving parts, longer pathways, there is so much more work to do, the big animal could break down much more quickly.

So Geoffrey West, Jim Brown and Brian Enquist discovered that nature gives larger animals a gift: more efficient cells. Literally.

The cells in an elephant slow down and do more work than the cells of a mouse. An elephant cell, lumpity-dumpities at a slower rate than the rattatat-tat of a mouse cell. They both wear out by a billion and a half beats, (yes, cells have metabolic or energy-using beats, too) but the elephant does it more slowly, all the way down to the cellular level.

When Professor West first saw this deep unity among living things, he was amazed.

Human beings used to fit into this pattern, but now that we have learned to drink safe water, wash and bathe and create medicines, we last longer than our size would predict.


So, by my calculations, well actually, according to The Straight Dope: we humans are living waaaaaay past nature's plan -- "Since the solar year consists of 525,948 minutes and 48 seconds, a quick calculation at the rate of 80 BPM gives us a ballpark figure of 42,075,904 beats per year, give or take a couple mill. A reasonable estimate for the number of heartbeats in a lifetime is about three billion."

A billion and a half beats, divided by 42+ million beats per year equals 35 years. 35 YEARS! Life expectancy is now around 70 years.

Maybe that's why we're fucking up the world so fast......


And what about all that exercise? Could this be my case for NOT exercising? They say a good aerobic exercise goal is 130 heart beats per minute. What am I missing? I know strong athletes tend to have a slower heart rate, but would'nt they be taking away from their total billion and a half? Everytime I see someone jogging, I think to myself - man-o-man why the hell are you doing that to yourself? Maybe it's those endorphines? While I was searching for some insight into this, I came across another post on the NPR segment which kind of ties in with what I was also thinking:

"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."

Lots to think about!

crossposted at BigBrassBlog

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