Stress can sensitise your pain system (and friends can help to desensitise it)
By Paul Bolger. Chartered Physiotherapist at Nano Physiotherapy, Kilkenny (www.nanophysio.ie).
Knowledge is power. Those following this series to date now know that stress is essential for survival – the ‘fight or flight’ response kept our ancestors alive. We also learned that excessive, sustained stress can negatively affect our health – and that inflammation and the immune system play a key role.
This week, we will consider how this impacts pain.
Stress is Painful
Excessive stress increases the risk of injury and impacts recovery from exercise, injury or surgery. Heightened levels of inflammation, which can result from stress, cause our pain system to become more sensitive.
The so called ‘pain system’ includes nerves in the body, the central nervous system (brain and spinal cord), the immune system as well as elements of the endocrine system (hormone system). Stress and inflammation play a role at every level of this system. We will focus on perhaps the simplest part of this system today – the nerve endings in our tissues.
Sensitive Nerves Send More Signals
There are many types of neurons (individual nerve cells) in the body – some of these are sensory neurons that send signals to the central nervous system associated with pressure, temperature, or chemical changes. Inflammation tends to increase the sensitivity of these nerve endings – causing them to fire and send signals more easily than they would otherwise.
The consequence of this is that more and more signals are sent to the spinal cord and the brain. For example, the nerve endings that send pressure signals, when exposed to inflammatory chemicals, will fire when a lower-than-usual amount of pressure is applied to them. Think of a time you were sick or run-down – did you feel more sensitive to heat/cold, pressure or bright lights?
More signals coming through to the brain and spinal cord from the body’s tissues play a role in the likelihood of something being painful.
This is just one way in which the pain system becomes more sensitive – we also see effects on the central nervous system (brain and spinal cord), the immune system and endocrine (hormone) system that are both pivotal in how we experience pain.
Sensitivity and Persistent Pain
Can you see how, for those with persistent pain problems, more sensitive nerve endings might contribute to them experiencing pain? If your nerve endings are more excitable, more sensitive, they are more likely to send signals to the brain. Their ‘threshold’ is lower – i.e. it doesn’t take as much pressure/ stretch/ temperature as it used to take to activate these nerve endings.
It is possible to go the other way – it is possible to DE-sensitise your pain system too. Our body is adaptable, it can change in many ways over the course of our lives. How do you think you might be able to settle down an overly-sensitised pain system? We will look into this in future articles.
So now you might have a slightly greater appreciation for the role that inflammation and stress can play in our experience of pain.
Social Support is a Great Stress Reliever
Social support is one of our most potent stress relievers. So, if possible, line up some time with a person or people who you like to spend time with this week – you will be doing your pain system a favour!
