Know your Neurobiology: Stress – Moving out of Homeostasis

Sensory Beginnings

Know your Neurobiology: Stress – Moving out of Homeostasis

April is Stress awareness month! So, we thought we’d take a look at what stress is all about. 

Our brain’s primary job is to keep us safe in the moment. It does this by ‘keeping an eye out’ for internal and external sensory cues that suggest something is amiss. Cumulative messages build pressure that overwhelms the homeostatic mechanisms available, becoming a demand that pushes us to do something to resolve the demand. 

We are pushed to act, to move away from a danger or discomfort and towards a state of safety. Our brain’s job is also to keep us safe in the future, it monitors what you did in the moment, what happened as a result, did it help/ mitigate the stress situation. Do you now feel safe? This learning enables us to anticipate. 

A stressor in the moment => I am thirsty => I am immediately given fluids. 

To keep safe in the future I need to find a reliable source of water for the long term.

Stress is not only essential for us to survive in the moment but in resolvable doses supports us to explore and find solutions, e.g., to thrive as well. To thrive we need a bit of stress to get us out there exploring the world, seek out new ways of being and learning new things. 

Stress is part of all life on earth and we, like all living creatures, are designed to experience stress.

Our stress state and homeostatic state are manifestations of the AutonomicNervous System (ANS), the headquarters, comprising the hypothalamus, cascades instructions to release neurotransmitters and hormones. These mobilise our responses during registered stressful events, or expected stress, and look to resolve the situation and regain homeostasis following this. 

“Stress,” is our sense of an undesirable state, of discomfort, of something’s not being quite right.

Stressors may broadly be divided into: 

  1. Physiological – the stressor has a physiological impact – oxygen level, water levels, sugar levels, blood pressure levels, the need to empty bowel/bladder.
  2. Psycho-social – the effect of the stressor is determined by the interpretation of an external situation. (Everly and Lating 2013)

“Stress Response” – consider the seven Rs: 

  • Our Autonomic Nervous System (ANS) senses / REGISTERS stressors and 
  • Oversees our stress RESPONSES to ensure we survive. Our behavioural responses (cues) to the stressor aim to get us back into homeostasis. These behaviours are observed and felt through our emotional reactions and actions and, hopefully, RESPONDED to via attuned others (co-regulation) or ourselves (self-regulation).
  • Our social/fight/flight/freeze behavioural actions are responses that look to RESOLVE and RESTORE homeostasis
  • We learn from the experience, it prompts us to adapt, REMEMBER and build a library of RELIABLE responses which we can use as a point of reference indifferent situations going forwards, so we can survive and hopefully thrive. 
  • The idea is that the more social support we are able to access (co-regulation strategies), the less energy we use and the quicker the stress response is resolved. This contrasts with the more demanding fight, flight and freeze responses.
  • The nature of building positive social support also enables us to become more RESILIENT against future stressors. RESILIENCE is the ability to restore homeostasis efficiently and quickly after coping with the stressful event. 
  • Positive social co-regulation is established through attuned sensory experiences of skin-to-skin interaction, cuddles, smell, taste, rhythmical auditory and vestibular experiences, mutual eye contact, interoceptive sense of homeostatic RECOVERY. The positive social co-regulation of predictable parenting means stress cues are consistently REGISTERED and RESPONDED to RELIABLY creating RESILIENCE in the system. 

During stress and the action of co-regulation we create chemicals such as oxytocin that modulate the stress response and act as buffers to anxiety and reduce the impact of stress on the body and brain. 

During a real or anticipated stress event, the ANS notes the need to move from homeostasis to a stress response. We therefore often begin to respond before the actual event has happened. This facilitates efficiency and minimal impact if the brain gets it right. If however, the ANS starts its stress response and moves us to behavioural resolutions of fight/flight/freeze but the environment does not require this level of response, we have a costly miss match. This response results in behaviours we may call defensive or over reactive. 

Extreme and consistent mismatches result in anxiety and mental health conditions, a potential constant state of readiness for expected stressors that may or may not actually exist. 

The constant presence of real stressors, or the prediction of expected but unreal stressors, will result in the same chronic and potentially toxic stress. If the stress response is not resolved or there is poor adaptation, the stress neurotransmitters, hormones and inflammatory cytokines continue to be produced. The long-term impact of this is on the cardiovascular, immune and regulatory systems, insulin production, epigenetic changes leading to a brain that continues to wire itself for survival, reducing the capacity to thrive.

What we know is that it is our experiences in early life that will guide and regulate the developing neurology and the lay down the predictions as to how to respond in the future. The perinatal period is a unique period where the fine‐tuning of the stress‐regulating system can be permanently programmed and impacts resilience and vulnerability for the long-term. 

Out of sync, too demanding, overwhelming, or abusive early sensory experiences that are not buffered and not easily resolved, or too few positive sensory experiences e.g., neglect, send wiring instructions to the developing brain demanding it “tune and prune” for stress. On the other hand, adults that nurture the young child can curate helpful buffering and repairing experiences that can“tune and prune” for resilience.