Have you ever wondered why, while exercising, you start getting stabbing pains in your neck and shoulder? Or perhaps why you get mid back pain when your stomach bothers you? Or even why we know that a heart attack is associated with pain that radiates down the left arm?
It’s possible you’ve never wondered. But hopefully you might still be interested in understanding why these things happen. Because they do, and there is a reason!
The concept of referred pain sparked my interest when I first learned about it in school last year. Because about 30% of the time I run, I start having obnoxious pains in my upper shoulder and neck. And I thought, “I’m not even using weights!!! Urgggghhh!”
In any case, the reason these pains occur is quite interesting. Every one of our internal organs has what’s called a “visceral” cover. Unbeknownst to us, this visceral layer is full of pain receptors and nerve fibers. Normally, we don’t consciously notice this. But once the visceral cover starts to feel irritated or overwhelmed, it will send rapid signals through our nerves to the spinal cord and up to the brain. Bringing it to consciousness allows us to take action to stop it.
To help explain the concept, I’m going to use a heart attack as an example.
1.) During a heart attack, the heart muscles cannot get enough oxygen to pump blood properly. The area of the heart that’s affected goes into crisis mode and sends pain signals to the spinal cord.
2.) It turns out that the entry point for the heart’s pain nerves in the spinal cord actually meets up and runs next to nerves that go to the left arm. It’s kind of like merging into a new lane on the freeway with another car in your blind spot. Normally, we can merge just fine with a little patience and attention. But occasionally, accidents happen, and we might hit the car that’s in our blind spot. And BOOM. Collision. This is what can happen with nerve signals. Because the signals from the heart are so close to the signals from the arm, they too can collide and confuse the message.
3.) Once the pain signals from the heart collide with nerves going to the arm, electrical and chemical signals will be carried back to the arm in the form of what we experience as pain. Then the brain gets a double whammy- on the one hand, there is crushing chest pain, and on the other there is shooting arm pain. Unpleasant, to say the least.
And there you have it! The same process occurs with the diaphragm (a huge muscle we use for breathing) and the upper shoulder/neck. So when we’re huffing and puffing and cardio-ing out, our diaphragms can get a little disgruntled and send pain/irritation signals up to the spinal cord that once again can get a bit confused and take the wrong turn.
The diagram below is a picture connecting areas of referred pain.
Just remember- you know yourself best! It’s entirely possible that more serious disease processes can lead to referred pain. Or perhaps it’s just your organs getting mad at you for pushing too hard. Make sure you see your doctor regularly just to make sure. This concept is very real and very interesting!!
Do you think you’ve experienced referred pain before?