Dr. Ethan Evert, DPT, CSMT
Pain is a universal experience. Everyone has experienced pain or knows someone who is currently struggling with it. Most people would agree that pain is unpleasant, but there are some that enjoy pain depending on the situation. For example, sports (get your mind out of the gutter) can be painful but enjoyable. To understand pain, it is important to define what it is. The International Association for the Study of Pain defines pain as a “sensory and emotional experience associated with actual or potential tissue damage1.” So why do we experience pain and why can it be so unpleasant?
Pain is not generated in the tissue or body part that we associate with discomfort, but rather in the brain.
Pain is a complex neurocognitive process where information is sent to the brain and evaluated for meaning. This means that pain is not generated in the tissue or body part that we associate with discomfort but rather in the brain2. This does not mean that pain is made up or not real. Our body’s nervous system works like an alarm system for your home. The brain acts as a control center and it constantly evaluates inputs for meaning. Pain is a warning from the brain that something may need our attention. It is alerting us of potential or actual danger 2,3. This system does a tremendous job of keeping us alive and healthy. If we did not experience pain, we would not live very long. A simple cut could be missed and become infected. A broken bone could become a serious issue if not treated properly. Unfortunately, our alarm system is not always accurate and the response is not always equal to the amount of actual tissue damage. It is possible to have high levels of pain with very little or no tissue damage. Conversely, it is possible to have little to no pain when there is a serious problem.
Even with an identical stimulus, studies demonstrate extremely different pain ratings.
We now know that pain is not a simple cause and effect phenomenon. There is no single spot in the brain that generates pain. Rather, this unpleasant sensation is generated by multiple parts of the brain. The path the stimulus takes to the brain, as well as the multiple pathways inside the brain, effect the end result. It is similar to an airline map, with many different routes to the same location3. Even with an identical stimulus, studies demonstrate extremely different pain ratings. The exact same stimulus will be felt differently from one person to the next. One person may feel little to no discomfort and the next will experience a high degree of pain or discomfort4. This happens due to the many variables your brain takes into account when producing pain. These variables include but are not limited to beliefs, stress, expectations, past experiences, and fear2,3. These influences are processed in real time and without us consciously considering them. Depending on the route the signal takes and what variables are present during processing the results can differ dramatically.
Pain does not equal tissue damage.
The good news is our bodies are ever evolving and changing. If we are currently in pain we can actively address the various inputs to reduce it and decrease pain as well as improve function. One way to decrease pain is to understand it. While this is just the tip of the ice berg, a basic understanding of pain can greatly diminish the unpleasant sensation of it and restore function. Remember that pain is a sensory and emotional experience associated with actual or potential tissue damage. There are plenty of examples or conditions that are associated with pain and disability. A few of these include auto accidents, bulging discs, and knee arthritis, but when looking at studies we find some surprising results. Did you know that the average demolition derby driver will experience 1500 crashes in their career but only 2% experience long lasting neck pain5? It has also been found that up to 40% of people have a bulging or swollen disc in their low back without pain6. Finally, a study found that only 50% of patients with arthritis in their knee on imaging experience pain7. These findings indicate that pain does not equal tissue damage and that the context in which pain occurs can have a significant impact on how we feel pain. In my next article, I will discuss how Physical Therapy can safely and effectively decrease pain.
- International Association for the Study of Pain. (2017, March 2). Retrieved from Pain Taxonomy
- Butler DS, M. L. (2003). Explain Pain. Adelaide: Noigroup Publications.
- Louw A, P. E. (2013). Therapeutic Neuroscience Education, Teaching Patients About Pain. Minneapolis : OPTP.
- SZ, G. (2017). Pain Management: Road Map to Revolution. Physical Therapy, 217-26.
- Somotas AC, S. T. (2005). Neck Pain in Demolition Derby Drivers. Archives of Physical Medicine and Rehabilitation, 693-696.
- Videman T, B. M. (2003). Associations between back pain history and lumbar MRI findings. Spine, 582-588.
- Munk B, L. E. (2004). Long-term outcome of mensical degeneration in the knee: poor association between MRI and symptoms in 45 patients followed more than 4 years. Acta Orthopedica Scandinavia Journal , 89-92.