Dr David McGrath

Spine Physician

MB BS (Hons) FAFOM, RACP, FAFMM
Master of Pain Medicine

Close to A Cliff Edge

Biology has many threshold situations. Complex dynamics are stable until, suddenly they are not. This operates at every level.
1. Cells suddenly die or transform into cancer cells.
2. People suddenly develop catostrophic illnesses, such as heart attacks,epileptic attacks, cardiac arrythmias,infections,critical vitamin deficiencies.

The likely reason, behind these sudden developments, is the convergent inputs into any phenomena.

Often, there are muliple positive and negative inputs which create a stable situation.

1. A+B-C+D+E-F-G+K+L+M+N=0

This implies a large number number of stable states. That is, an increase in (A), could be balanced by an increased negative from C,F,G individually or in combination and still be stable. Or more simply, an increase in (A) could be matched by a decreased positive from B,D,K,L,M,N singly or in combination.

The whole system of {A,...N} may be pushed to a situation where, there is little or no reserve.
1.All of the positives B,D,K,L,M,N have been driven downwards, by a rising (A)
2.All of the negatives C,F,G have been driven upwards, by a rising (A)

Physiologically, there may be nothing much to observe or feel. The situation is still stable.
Now that the adaptive reserve has been exhausted, it only takes one further event in any of the variables to push the system into a positive or negative summation. (ie unstable)

We could further refine the model, by
1.Introducing loss of dynamic range of some of the components (aging,injury)
2.Limited capacity to involve some of the components. (neglect )

This means some of C,F,G,N are not part of the equation.
A+B+D+E+K+L+M=0
This reduces the structural reserve of the system.

If this is a reasonable model, of complex physiology, we need better ways to detect a system under stress, defined as one lacking adaptive reserve.

(to be continued)