When people think of their heart beat a common image is the electrocardiogram.  It displays the electrical signals generated by your heart, and in the movies good health is affiliated with clockwork like regularity.  It’s only when there are large variations that something goes wrong.

Tranquility seems like it’d be a good thing for your body, but many times that’s not the case.  Your heart would be a very good example.

I had never given too much though to the workings of the heart, and always assumed it worked like a locomotive, relentlessly pumping blood throughout your body.

It turns out that’s not the case.  I just finished reading a fascinating paper that shed a lot of light on how your heart works, and I was very surprised by two facts:

1. The frequency of your heart beat is random and the time between beats can’t be predicted with accuracy.  (The technical word for this is “stochastic”).
2. The loss of this randomness is highly correlated with a variety of coronary diseases.

You would instinctively think that a regular heartbeat is good, but people who are elderly and/or have heart problems routinely begin to display heart beats that begin to trend towards high or low frequencies, which is a serious risk factor for disease.

The Butterfly Effect

Your heartbeat is caused by electrical currents that pass through its different chambers.  The propagation of electricity is extremely sensitive to a wide variety environmental factors which all eventually influence each other as they travel downstream.

What this amounts to is an outcome (the heart beating) that cannot be predicted in a deterministic framework.  The most famous example of this sort of phenomenon is the one used by weatherman.  A butterfly flaps its wings in Taiwan and the downstream interaction effects influences the formation of a tornado in Tulsa, Oklahoma.

And maybe even more importantly,  even tiny deviations in initial starting conditions can lead to entirely different outcomes which elude prediction.  So it doesn’t matter how much you know about something, because without perfect information you’re just as far off as if you knew nothing.

In your body this means small differences in membrane potentials, ion concentrations, oxygen intake, etc, all blend together for changes in electrical currents in your body that look like a random walk.

However, an important point is that this unpredictability is good for us, not something to be feared.  The lack of any distinct pattern usually means the overall system is resilient and robust to unforeseen shocks.

Preference is weakness.

Seem Weird?  Chaos Creates Order All the Time.

Even though our heart beats are statistically random, it still doesn’t seem intuitive since it seems so regular.  I mean, it’s not like we go 6 or 7 minutes without a heartbeat.

So how do you put two and two together?

The key point is that the periods between your heartbeat can’t be predicted, and you can’t use the available clues given by your body to make inferences about the periods between beats.  The heart beat is an emergent phenomenon of decentralized electrical signals.

And to make a broader point, seemingly chaotic systems eventually self organize into contraptions that seem non-random all the time.  In fact, it might be the de facto cause of most biological complexity.

Scientists like Benoit Mandelbrot and Steven Wolfram have shown that simple rules easily create very complex phenomenon that exhibit unpredictable behavior, even though they still seem bounded by some broader sense of order to the naked eye.  Most systems you observe in nature apparently follow this pattern.

Does Exercise Train Us or Untrain Us?

Whenever I exercised, I always assumed I was “training” my body for something, sort of how you walk a dog and tell it to sit or heel.  After a while it just learns to succumb and act like a good boy.

However, in light of the points we talked about today I’m inclined to reconsider.  Perhaps exercise is healthy because it makes the dynamics of our body less predictable and more random, which makes it more robust to stress, and healthier overall.