Can Pain Be Measured?

You know that question they ask? The one where they want you to rate your pain on a scale from one to ten. Sometimes there’s even a chart with a smiley-faced “one” that progressively changes into a very unhappy “ten”. I hate that question. RA-related pain can vary not only from day-to-day but minute-to-minute, so how do you quantify it?

I once built my own pain scale based around Disney’s Seven Dwarfs. The scale ranged from “Happy”, meaning no pain, to “Doc” when it hurt badly enough to see a doctor, to “Dopey” when I had to take enough pain medicine that I wasn’t functioning very well. It wasn’t any more useful than the “one-to-ten” scale, but it was a lot more fun.

Doctors and patients both will tell you that pain is very subjective. What is extremely painful for one person can be perceived as mildly painful for another. There is a lot of discussion of why this is including individual tolerances for pain as well as associated emotional elements. And while perception really is often reality, it seems that it would be helpful for everyone if there were clinical, quantitative ways to actually measure pain.

Which brings me to something very interesting that’s been happening to me.

For years my heart rate when I wake up in the morning has been around 85 beats per minute (bpm) which is on the higher side of normal. Just getting out of bed sends the rate well over 100. Of course, actual work or stress causes the rate to go up as well. The day I left full-time employment last fall, my resting heart rate was 101 bpm. During the first week off work, the rate dropped steadily back to my normal mid-80’s range, clearly demonstrating lower stress levels. It’s stayed at that level until recently.

I discussed my heart rate with my doctor, expressing concern that it continued to be higher than I’d like. She pointed out that at the time, my RA was not well controlled and had not been for some time. She reminded me that pain causes stress – even if you’re not consciously aware of it. Stress, as we know, increases heart rate.

After more than a year of struggling with an ineffective RA treatment plan, my rheumatologist has prescribed a more aggressive protocol that seems to be improving the situation. While I still have some joint pain and swelling, the bone-wrenching fatigue that I previously had is much, much better. And (here is the interesting part), my heart rate has dropped down into the mid-70’s, which is lower than I can ever remember it being.

I don’t know for sure what caused this improvement, but I am speculating that since I’m in less pain, my body is experiencing less stress and therefore, my heart rate is lower. During the time in question, I haven’t made any other lifestyle changes that would account for this. Further, none of the drugs in my treatment plan are known to cause a lowered heart rate – just the opposite. Following the Occam’s Razor philosophy that the simplest explanation is usually the correct one (e.g., when you hear hoof beats, think horses, not zebras), I have to believe that my improved pain levels have also resulted in an improved heart rate.

I’m not suggesting that heart rate alone can be used as a litmus test for pain. There are far too many variables that can cause it to fluctuate. But it does raise the question if there isn’t a combination of clinical measures that might be used to form a more objective picture of patient pain and, consequently, the effectiveness of treatment plans.

This is no doubt an elusive endeavor. In 2013, the New England Journal of Medicine reported that scientists succeeded in using brain-based neurological signatures to accurately measure pain associated with heat. In simple terms, they measured brain waves and were able to determine when pain from heat crossed from uncomfortable to painful. This is a huge step in the right direction, but it requires brain imaging and, right now, only applies to a specific kind of pain. I feel the true objective is a profile from readily available patient readings (heart rate, blood pressure, respiration, etc.) that can be assimilated into an objective pain profile. This will be an invaluable tool for doctors and patients alike.

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