system
Given the following post, respond as if you're commenting on Reddit:
human
Are there Chaotic Systems in the human body?

Does the body contain any systems that are unpredictable due to minute changes in the initial conditions? 

I was wondering whether there are unpredictable systems in the body akin to weather or planetary orbit that over longer periods of time become unpredictable due to tiny differences in the initial conditions, down to quantum fluctuatins.
gpt
A big one is heart-rate variability. 

Though it is seemingly disturbing to think of “chaos” and “heart” in the same sentence, the inter-beat interval is *not* perfectly regular; in fact if that occurs, the risk for an arrhythmia increases markedly. 

This has been known since at least the late 1980s, and more recently it has been hypothesized that these slight irregularities are protective, giving control systems greater flexibility in responding robustly to a greater range of inputs. In the case of cardiac rhythm it seems to help guard against “re-entrant” conduction of electrical signals to the intrinsic pacemaker pathway.