Michael White, a victim of repetitive strain injury, needs to type slowly as he tells us the scientific and evolutionary side of pain.
I suffer from an injury common in our keyboard- and mouse-dependent society: repetitive strain injury. This grab-all term captures a variety of medical problems that afflict hundreds of thousands of working adults in the U.S. and cause somewhere on the order of tens of billions of dollars of lost economic productivity. What this means for me is that during every waking minute of the last 18 months I have felt pain ranging from “moderately distracting” to “downright debilitating.” It hurts to type, to pick up my child, to hold a glass, or to just sit in a chair. And, in spite of my hundreds of thousands of fellow-sufferers, I am embarrassed about my situation.
It is embarrassing to be debilitated. My emails are invariably prefaced with ‘sorry for my slow reply.’ I skip non-essential meetings because I can’t bear to sit in the chair for an hour. I make excuses for my slow progress on my research. I stand up at my desk and do odd-looking stretches. And I reek of Ben-Gay. I am a scientist, surrounded by competitive, workaholic people, and I hate to appear lazy. While I was not exactly a workaholic in my pain-free, earlier life, I do like to think of myself as driven, motivated, and hard-working. But instead of ability, I have a debility, a weakness, a lack of strength. I cannot be who I want to be. I’ve largely shuttered my blog, reduced my workouts, shelved my writing projects, and limited my computer time to the bare minimum sufficient to keep my research projects from regressing. My pain has changed who I am.
Given how debilitating chronic pain can be, it’s a little jarring to think about the tremendous biochemical machinery that your body deploys just so that you can feel pain. You are highly rigged with thousands of neural sensors that can generate feelings of pain related to a dizzying variety of anatomical systems. But this is not the complicated part. Operating within each pain neuron are dozens of different molecular machines. There are the voltage-gated ion channels, embedded all along the neural membrane, that are responsible for transmitting an electrical pulse along the neuron. At the neural ends, this signal is transmitted to the next neuron in the relay, via the secretion of chemicals called neurotransmitters, which are carried through the cell in little lipid balloons to the cellular membrane, where they are dumped out into intercellular space. These neurotransmitters are quickly picked up by receptors embedded in the neighboring neuron, and the whole signal transmission process begins again. Backing up the main act of neurotransmission is a huge support staff of metabolic and transport proteins that keep the lights on, carry out supply chain management, and relay genetic information from the nucleus in the form of messenger RNA. Neurons being among the largest cells we have, this is no trivial task, and it’s not surprising that neurons are a relatively late evolutionary invention, as far as cell types go.
Every element of pain’s machinery has a very specific evolutionary history going back more than five hundred million years. Pain is no random development. The survival value of our ability to feel pain is obvious from the frightening examples of those unfortunate people who can’t feel pain. From a review of pain physiology:
Pain is one of the primitive behaviors that is highly conserved among species and is critical for survival when facing environmental stresses. In an extremely rare occurrence, families in a remote village of Pakistan were discovered to completely lack the capability for nociception. The resulting lack of pain appeared to manifest with frequent injuries ranging from bone fractures and extensive burns to accidental death.
Every single gene involved in pain perception is a DNA-encoded record of a hard-won evolutionary success of the distant past. The structure of each gene determines the precise functioning of the corresponding protein, and each gene is accompanied by information that determines when and where that gene will be expressed. This is what ensures that the machinery of pain is produced specifically in your pain-sensing neurons, in the quantities required. The result is a marvelous, exquisite, highly complex, and amazingly robust system that transmits signals to your brain, where they are transformed into a feeling of sharp, throbbing, or dull pain somewhere in your distal anatomy.
The major lesson I take away from all of this is that physical pain is something to take seriously. Your body puts a tremendous effort into producing it, and we disregard the message at our peril, in spite of societal pressures to hide it or walk it off. The second lesson for me is that we’re remarkably lucky in the 21st century. As debilitating as my pain has been, I have some prospect of relief. I can buy painkillers, I can visit my doctor for a reassuring discussion about my full recovery, and ultimately, if necessary, I can take time off work and still receive some compensation. My hope for relief stands in contrast to sufferers just a half-dozen generations back, who, like the gout-ridden Ben Franklin, had little reason to hope for any improvement, as they hobbled through their last decades of life. Even more disturbing is the suffering evident in the damaged and arthritic skeletons of those Neanderthals that struggled against starvation 100,000 years ago.
Pain’s vast machinery and history may be impressive, but my immediate concern is the impact of pain on who I am. I don’t want to be a boring father, a negligent husband, or a mediocre scientist. Pain may serve a functional purpose, but somehow, via the cellular machinery of frustration and embarrassment, it has an overwhelming effect on more than just my wrists.