In Part 1 we talked about the different types of stresses on the nervous system.
In this post we’re going to look at how your nervous system adapts to stress, and how you can use that knowledge to improve your overall health.
Most patients expect us to ask about their pain, and questions about their occupation and exercise habits don’t seem too unusual either. But many don’t expect us to ask about their wider health and lifestyle – questions about diet, sleep habits, alcohol and caffeine intake for example.
As we mentioned last time, there are 3 types of stress which affect the nervous system: physical stress, biochemical stress, and psychological stress. Each individual stress will usually cause the body to respond in a specific way – such as a fever from an infection, or back pain from poor posture. However, all stresses also trigger a generalised response to stress, and the effects of multiple smaller stresses combine to increase this general response. This is known as “General Adaptation Syndrome”, a term coined in the 1930’s by the physician Hans Seyle. He described 3 phases of stress response: alarm, resistance, and exhaustion.
During the alarm phase, our bodies prepare to respond to the stress. This is commonly known as the “fight or flight” response, where adrenaline, cortisol and other “stress hormones” are released. Blood pressure increases, blood flow is diverted to muscles, and we feel we are on “high alert”. This situation isn’t sustainable for very long, so if the stress persists we move on to phase 2 – resistance. Here we compensate to reduce or repair the effects of the stressor, and try to restore things back to normal. If it’s an infection, we mount an immune response. If it’s a work deadline, we stay late at the office.
However, this has its limits – if the stressor continues beyond our nervous system’s ability to adapt, we begin to struggle. Our energy supplies are depleted, and we can’t keep up to the demands of adapting to the threat. We become less able to adjust to other stresses, and are vulnerable to illness and injury. The nervous system struggles to regulate our normal physiology and goes into “defence mode”. Common effects include muscle tension, aching and stiffness. However, long term stress can have more widespread effects, such as increasing pain sensitivity and inflammation, and decreasing circulation and muscle strength.
We can often cope for quite a long time in this state, but at the cost of a reduced ability to respond to other stresses – essentially reduced health. Our nervous system can only tolerate so much stress at one time. This is called our “Generalised Adaptive Potential”, or Stress Threshold. This is also a pretty good definition of health – our ability to resist additional stresses. Some stress is unavoidable, and we have evolved to cope with them to a degree. But when we go over our Stress Threshold, it pushes our body and nervous system to phase 3 – exhaustion. We’ve all spent short periods here – think of the “run down” feeling you get when recovering from the flu. If the stresses are removed (you fought off the virus), things calm down and you recover.
But what if the stress isn’t removed, or not enough is removed? What if you’re still coping with an aggressive boss, or partying heavily every weekend? This is the real danger, where stress can have more severe long-term consequences.
The problem with constantly exceeding your stress threshold is that over time this causes it to lower. You become less able to adapt to stress in the future, even if you are able to recover from the original problem. Previous stresses which weren’t so bad now take a greater toll on your health. The danger here is the potential for a downward spiral as the nervous system becomes more easily overloaded and then less able to cope.
- “Everyday stresses” – It’s below the threshold, so you manage without being too aware of it.
- Short term high stress (e.g flu) – Slight reduction in the stress threshold, but it recovers quickly.
- Long term high stress – Big reduction in the stress threshold.
- Exhaustion – “Everyday stresses” now exceed the stress threshold, so it is unable to recover as easily.
So what can we do? We have to be realistic – there will always be some stress on the body, and some stresses are not easily removed. This is okay as long as we stay safely below the threshold. The trick is to identify stressors which can be removed or reduced and work on those. Chiropractic treatment is very effective at both reducing the stress on the nervous system and increasing the stress threshold, but making changes to your lifestyle is just as important.
Looking for other stresses you can reduce will help you stay below the threshold, so that your nervous system can recover more easily. Once you’re safely below your threshold, we can work to increase the threshold itself: for example, specific exercise can help strengthen joints and muscles to improve their ability to adapt to stress in the future. It can also help you plan for the future – if a stressful event is on the horizon, you can prepare by removing other stressors beforehand. If you have a busy month at work approaching, taking time to catch up on sleep, eating well and a little exercise will improve your ability to cope with it.