Can Pain Be Explained with an Equation?
Doctors and researchers have written a lot about how pain works, but it’s often hard to understand. In 2020, the International Association for the Study of Pain (IASP) updated its definition of pain:
“An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage.”
This means pain is not just about injury. It’s also shaped by your emotions, thoughts, and life experiences.
I’ve worked with people who have persistent pain for over 30 years. Helping people understand how pain works is a big part of helping them feel better.
This became clear to me after a wasp sting.
The Wasp That Taught Me About Pain
One morning, I was cycling to work when I felt a sharp sting on my leg. I looked down and saw a wasp. Instead of panicking, I paid close attention to what was happening.
For the next 45 minutes, my pain went up and down. Sometimes it really hurt. Other times, I didn’t notice it at all.
That ride gave me a big idea. In order to explain how pain works, I came up with an equation to explain pain:
P = (N – MWP) + (NO – PO) + ATBP + PVOP
Let’s break it down.
How Pain Works: The Pain Equation Explained
P = Pain
This is the pain you feel right now.
N = Nociception
This means your body has sensed something harmful, like an injury or heat. But sensing harm doesn’t always mean pain. Your brain decides whether it hurts or not.
MWP = Movement Without Pain
Moving in a way that doesn’t hurt can help reduce pain. When you move, your body sends signals that block pain. Exercise also releases chemicals that make you feel better.
NO = Negative Outlook
When you’re stressed, scared, or feeling low, pain can feel worse. These emotions activate the same brain areas as pain. This is a huge part of how pain works.
PO = Positive Outlook
When you feel happy, safe, or connected to others, pain often feels less intense. Fun activities help your brain fight pain.
ATBP = Attention to Body Part
The more you think about the pain, the more you feel it. If you’re distracted, pain often fades. That’s why pain can feel worse at night when you’re not busy.
PVOP = Previous Volume of Pain
If you’ve had a lot of pain before, your body may become more sensitive to it. Your brain and nerves learn pain—this is called “central sensitisation.”
What If My Pain Is Worse?
You might think, “My pain is much worse than a wasp sting.” And you’re probably right.
But this equation still helps. For example, shark attack survivors often don’t feel pain at first. And some people feel strong pain even without any injury.
Pain is about how your brain sees the situation—not just the damage.
Use the Equation to Help Yourself
Write this down:
P = (N – MWP) + (NO – PO) + ATBP + PVOP
Now ask yourself:
- Can I move more without pain?
- Can I find ways to reduce stress or feel more positive?
- Can I distract myself from focusing on the pain?
Even small changes in these areas can help reduce pain.
Final Thoughts about how pain works
Pain is real, but it doesn’t always match the amount of damage. Your brain plays a big role in how pain works.
If you understand this, you can take back control. Try things that boost your mood, get you moving, and keep your mind busy.
I hope this helps you understand your pain—and feel better.
If you have ideas about this pain equation, I’d love to hear them.
Stay active and stay hopeful,
Gavin Routledge
Registered osteopath
About the author
Clinic Director at Active X Backs, in Edinburgh, Scotland. (https://active-x.co.uk/). Co-author of “The Back Book” in 1997 with Gavin Hastings OBE, and author of “Active X Backs; an effective long-term solution to lower back pain” in 2017. Gavin graduated as a Gold Medalist (awarded for Conspicuous Merit) in 1991 from the British School of Osteopathy. He was Vice Patron of the British School of Osteopathy from 2005-2015, and a Director of the British Society of Lifestyle Medicine 2018-19. He has an MSc in The Clinical Management of Pain from the University of Edinburgh, and runs regular free webinars for those affected by lower back pain and sciatica.
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