Allostatic Load and Stress by Soph Shephard
Allostasis is the ability of our body to keep our body systems operating within a “normal” range as we go through life. This system is so advanced that it can even predict and respond to potential threats, not just events or situations that have actually occurred. Allostatic load can be thought of as the cumulative burden or stress placed on our body to maintain “normal” function. Stress in this setting doesn’t just mean psychological stress - it also means any pressure, threat, or increased demand on our body systems.
Lots of different factors (stressors) can contribute to an increased allostatic load:
Illness/injury
Situational/contextual factors
Stress/emotional state
Poor sleep
Poor diet
Smoking
Drug/alcohol intake
If our allostatic load remains consistently high, it can mean our system is constantly working in a state of “fight or flight”. Biologically, this makes sense - back in the day when we were cavemen, our main stress/threat to our safety involved very physical threats, like sabre toothed tigers or fighting members of other tribes. So having an increase in our sympathetic nervous system (fight or flight) was helpful, as it let us respond appropriately by increasing our heart rate and blood pressure, priming our muscles, and increasing our alertness. In turn, systems that are not as essential in those situations (e.g. digestion, longer term hormonal regulation, higher level reasoning/memory) get turned down.
However, in our modern life, it is very rare that our stressors are as short lived as those encounters. Nowadays while our physical threats may be less, we are exposed to more subtle but chronic stresses. Our systems are not as well equipped to deal with this - those responses in the body that were very helpful in fighting off sabre toothed tigers become unhelpful if they can’t switch off. Prolonged sympathetic nervous system activation can lead to a wide range of symptoms, including:
Increased blood pressure and heart rate
Increased muscle tension
Increased levels of stress hormones
Digestive upset and bowel/bladder dysfunction
Fatigue
Thyroid dysfunction
Increased risk of infections
Concentration/memory problems
Sleep disturbance
Hyperalertness/trouble “switching off”
Anxiety/depression
Pain/increased sensitivity
And many more
We can think of allostatic load using the “Cup Analogy” - we all have a cup (some bigger, some smaller), which gets filled up as we are exposed to stressors. We might have our cup filled a little bit by poor sleep, and a bit more by suboptimal diet, then brought almost to the brim by a busy week of work and work-related stress. Adding in some strenuous physical work may then cause the cup to overflow. All of these things combined lead to a stress response in the body, which can include pain. It isn’t unusual to find that many physical injuries or pain (especially back and neck pain) occur in the context of many other stressors. Managing pain (particularly persistent pain) often involves looking at all factors that may contribute to allostatic load, and treating holistically. Over time we can also cause our system to adapt and develop so that our cup is bigger, giving us more capacity to cope with stress.
So if you’re struggling with poor health, pain or fatigue, it may be worth asking yourself - what’s filling my cup? Identifying some of these factors and discussing them with your health care professional might be an important step in improving your health and wellbeing.