The homeostasis model has contributed immeasurably to the theory and practice of scientific medicine, so to criticize it might almost seem absurd. Yet, all scientific models eventually encounter new facts that do not fit, and this is now the case for homeostasis. In physiology, evidence accumulates that parameters are not constant. And their variations, rather than signifying error, are apparently designed to reduce error. In medicine, major diseases now rise in prevalence, such as essential hypertension and type 2 diabetes, whose causes the homeostasis model cannot explain. For in contrast to the hypertension caused by a constricted renal artery and the diabetes caused by immune destruction of insulin-secreting cells, these newer disorders present no obviously defective mechanism. And treating these diseases with drugs to fix low-level mechanisms that are not broken turns out not to work particularly well.

Homeostasis describes mechanisms that hold constant a controlled variable by sensing its deviation from a “set-point” and feeding back to correct the error. Allostasis describes mechanisms that change the controlled variable by predicting what level will be needed and overriding local feedback to meet anticipated demand. Thus allostasis considers an unusual parameter value, not as a failure to defend a setpoint, but rather as a response to some prediction. So when chronically high levels of carbohydrate evoke chronically high levels of insulin, its receptors and their downstream mechanisms naturally reduce their sensitivities. Thus this model attributes diseases such as essential hypertension and type 2 diabetes to sustained neural signals that arise from our own behavior. Consequently the allostasis model would redirect therapy, away from manipulating low-level mechanisms, toward improving higher levels in order to restore predictive fluctuation – which under this model is the hallmark of health.

high carbsSimplistically for type 2 diabetes if we keep our carbohydrate to normal levels our body will produce the insulin we need. That is to say everything else being equal if we change our diet our body will increase our sensitivities and not need to override local feedback. Further to this point researchers in Denmark reported that, among individuals with Type 2 diabetes, those who were randomly assigned to a program of walking at alternating levels of intensity (alternating fast and slow walking, every three minutes) had greater sensitivity to insulin – had lower blood sugar – than those who were assigned to walk at a consistent pace with the same total energy expenditure, or a non-trained control group.

Homeostasis versus Allostasis

This has implications for brain function and mental disorders,” from Peter Sterling, co-developer of the allostasis paradigm.

In this article, Sterling brings his message trenchantly to the psychiatric community. As you have learned homeostasis presumes the existence of “normative set-points” for neural functioning. Treating the brain to attain these set-points is the justification for psychiatric medications, but there is no reliable scientific basis for such a model of brain functioning and mental health. In contrast, allostasis recognizes the need for systems to have dynamic responsivity to a range of circumstances. Under the allostasis paradigm, mental health requires a capacity for flexibility and responsiveness to the full range of signals from many sources. Such sensitivity is typically blunted by psychiatric medications, which thus “can make matters worse.”

The brain and body evolved to interact with a world that is constantly changing.  When the brain and body move with a degree of variability and flexibility – as described by allostasis – such movement is likely to be healthier than moving in a strictly consistent way, which can lead to the rigidity or “stuckness” that leaves us vulnerable in so many ways. Brainwave Optimization™ is the first step in regaining this flexibility.