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An interesting recent study caught my eye for 2 reasons. First, researchers have exciting findings that would dramatically change our understanding of certain kinds of pain and its treatment. More on research in a moment.
The other reason this story caught my attention is that almost all of the headlines I examine this research failed to incorporate two key words: “in mice.” One article didn't mention the proven fact that it was an animal study for a full 248 words into the story! Regardless of how interesting the outcomes are, they deserve a giant star because their relevance to humans is uncertain.
Sleep deprived and in pain? Caffeine may fit higher than ibuprofen.
The researchers studied mice that were either well-rested or sleep-deprived and subjected them to unpleasant stimuli, including contact with a hot plate, cold or stress. The magnitude and speed of their responses were measured.
Here's what the researchers found:
- Lack of sleep appears to extend pain sensitivity.
- Restoration of normal sleep reversed the exaggerated pain response.
- “Wake-promoting agents” (including caffeine and the drug modafinil) also reversed the exaggerated pain response.
- Ibuprofen and morphine didn't have the identical effect as wag-promoting agents.
The suggestion here is that sleep deprivation may increase pain perception, and that restoring normal sleep or taking stimulants that increase alertness (similar to may be experienced after drinking coffee) may reduce pain on this setting. May reduce sensitivity higher than common and stronger pain relievers.
From mice to men… and girls
As mentioned, the relevance of animal studies to humans is just not at all times clear. In fact, it is not uncommon that the outcomes of clinical research conducted in mice or other animals can't be replicated in humans. This may be very true for something as complex and subjective as pain.
The relationship between sleep and pain
That said, there's precedent for a possible link between pain and sleep deprivation in human disease. Fibromyalgia is common within the (human) population and is characterised by chronic, body-wide pain. The cause is unknown, but one leading theory suggests that poor sleep quality may play a job. Treatments that improve sleep quality might also help with fibromyalgia symptoms.
what's next?
The obvious next step is studies in humans. It can't be easy. The trial involved continuous monitoring of brain waves in rats by placing electrodes on their scalps, depriving them of sleep, delivering pain and closely observing their responses. An analogous experiment in humans could be not possible. And, in fact, there are ethical concerns for any study that intentionally causes suffering to its subjects, be they animals or humans.
This study jogged my memory of something I learned in medical school. I used to be taught that one of the vital common causes of headaches was caffeine withdrawal. An effective “treatment” includes coffee, one other caffeinated beverage or food, or a headache medicine that incorporates caffeine. But now I'm wondering if coffee's pain-relieving properties might need less to do with caffeine release and more to do with the outcomes of this study. It could also be that wakefulness-promoting agents reverse pain sensitivity in sleep-deprived people, as present in mice on this study.
This recent commentary may change how we understand and treat certain kinds of pain—or it might just apply to mice. Either way the outcomes are interesting. The big query is: Are they essential?