Homeostasis: The Bedrock of Health

Homeostasis, our mind and body’s default mechanism, consists of a series of overlapping and complementary resources, programmed through repeated behaviours into a self regulating feed-forward and feedback maintenance system. This system of checks and balances allows fluctuation around established and reinforced norms, with biological systems kicking in like a thermostat to keep systems functioning within this defined range.

Any stress or load added to the system will take resources from other systems until this equilibrium can be re-established. The body strives for efficiency: if one system doesn’t use its’ resource, this will be repurposed for another. The body will not waste energy or nutrients preserving the function of something that has fallen into disuse, so that system will lose fitness and resilience unless it demands resources in turn.

Yet this equilibrium can be changed. Repeated stress or load at the higher level of tolerance will, with enough relaxation and repair time, result in adaptive changes increasing the resource within that system. This makes the load easier to withstand, placing it within the middle of tolerance, not the upper end. And when this happens there will be less need for the load to take resources from other areas. The system becomes more resilient. Muscles can lift more weight or can endure more for longer before fatigue sets in. Cardiovascular fitness affords a lowering of blood pressure and heart rate at rest. This mechanism of gaining fitness is well understood in the musculoskeletal and cardiovascular systems, but is true for most if not all others systems too.

Yet in order to improve the fitness and resilience of any system it must first be able to withstand the short term load. Exercise, in addition to demanding resources from other systems, is inflammatory. It is the adaptation afterwards that increases load tolerance and has a positive effect on other systems. For example, muscle bulk provides an anti-inflammatory effect outside of the performance of exercise and provides a reservoir for the immune system. (Those suffering with a reduction in muscle bulk, sarcopenia, are twice as likely to contract a hospital acquired infection.) The lessening of visceral fat secondary to endurance exercise stops this fat executing a proflammatory effect and adversely affecting metabolic health through an increase of systemic inflammation. But this adaptation takes time, and if the load is intolerable, you will make yourself unwell. We all have a breaking point, this is not restricted to those with chronic illness who have to limit their activities to stay within their energy envelope and avoid relapses.

Illness needs a different approach because it introduces a higher and continuous load. Any resilience has been overcome, the load intolerable. The mind and body will respond by placing all hands on the pump with many resources diverted to fight the illness. The stress / relax cycle is completely disrupted, additional stress will not be tolerated and relaxation / repair time is impossible because your body continues to fight against the cause of your ill health. At this point you may need your systems to release their stored nutrients to fight off illness rather than take resources away from it. You need to rest, for long enough, from competing physical and mental stressors, allowing the utilisation of these resources for enough time to allow your equilibrium to be re-established.

If your illness is short-lived, returning to your previous life will take effort but the equilibrium can be quickly re-established. This is when the delay of adaptation works in our favour: returning to health after a brief illness is not as difficult or lengthy as establishing fitness from scratch. If there is a delay in recovery for whatever reason there is a risk that the unhealthy equilibrium becomes established and we move from acute to chronic illness: a generally accepted rule of thumb is a timeline of 3 – 6 months. This doesn’t mean the equilibrium cannot be reset again, but it means it is harder and will take much longer: and if you are still unwell your available bandwidth to affect an increase of fitness is much smaller too: particularly if you have competing obligations such as work or children.

If you try to return to your life too quickly or when you are still unwell, adding more stress to the system, you run the risk of developing chronic illness through slightly different means. Overloading biological mechanisms without respite can cause the body to turn on itself in the form of autoimmune illness, or these intolerable, persistent loads cause systems to malfunction.

The establishment and maintenance of good health is and of itself a worthy pursuit, as it affords you the energy and resilience to enjoy your life to the full. To aspire to optimum health, there has to be a balance between behaviour that introduces stress into the system, to gain fitness, and the relaxation / repair time to affect an improvement in function. Stress or load is inflammatory, but repeated performance within tolerance will train the system to withstand more and be able to assist when other systems are challenged by illness.

In future posts, I will look at the ways in which we can maximise our quality of life, what happens when it goes wrong and what to be aware of when engaging with the wellness industry. I hope these series of blogs empower people with the right information to self manage their health, using best evidence and my practical experience of working with patients for the last 30 plus years.

Sue Julians Written by:

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