You may have heard that from the dental chair to the labor and delivery room, things are even more painful for redheads.
But do redheads really feel pain differently than others?
Anecdotal reports from anesthesiologists and various animal and human studies suggest that having red hair is associated with impaired sensitivity both to pain itself and to painkillers, according to a 2023 review in the journal. Anesthesiology and perioperative sciences.
However, details about how redheads’ pain experience differs remain somewhat unclear, in part because previous studies have all investigated different forms of pain, review co-author Jaideep Panditconsultant anesthetist at Oxford University Hospitals NHS Foundation Trust, told Live Science.
Related: How did doctors perform surgery before modern anesthesia?
Studies suggest that redheads are more sensitive to certain types of pain, but not others, Pandit said. A study found that redheaded women were more sensitive to temperature-related pain and that lidocaine, a nerve blocker, was less effective in managing their pain than that of dark-haired women. Another study found that redheads were less sensitive to pain from electric shocks than the others.
Likewise, the connection between ginger strands and pain management is not simple. There is data suggesting that redheads need 20% more general anesthesia to stay sedated, and they also need more local anesthesia to keep the pain at bay. But data shows that they are actually more sensitive to opioids, including mu-opioids, like morphine and fentanyl, and kappa-opioidsalthough the latter effect may be specific to female patients.
To complicate matters, a 2015 study found no difference between redheads’ and other people’s responses to anesthesia or painkillers, so the data are somewhat mixed.
Although redheads may perceive some pain as more intense, they also have a higher pain threshold, according to Dr David Fisherchief of dermatology at Massachusetts General Hospital, who published a Study 2021 on pain in red mice. Red-haired mice and humans initially seem somewhat impervious to pain. They only perceive pain when it reaches a higher threshold, but then redheads feel it more intensely than others, Fisher said.
The painful experience of people with fiery hair is difficult to explain, in part because humans are so genetically complex that it is difficult to identify a single genetic cause for their experience, Fisher told Live Science.
Fisher and his lab therefore studied pain in mice, in which they had complete genetic control. With few exceptions, red hair is produced by mutations in the Melanocortin-1 receptor (MC1R) gene; This gene helps control the type and amount of pigment in hair, skin, and eyes. Fisher’s team studied mice that were genetically identical, except that they carried a variant for either red or black hair.
To avoid bias, the researchers crossed these mice with an albino strain, so they carried the genes for red or black hair but produced no pigment. “We found exactly one difference in pain threshold between red and black hair, even when they weren’t producing any pigment at all,” Fisher said.
Why this is the case is complicated. The MC1R gene affects a protein found in melanocytes, the body’s pigment-producing cells. Fisher’s team found that in addition to changing this protein, the red MC1R variant also causes mouse melanocytes – and, theoretically, human ones – to produce less of a substance called POMC.
POMC is divided into several hormones that affect pain and opioid sensitivity by helping to control the activity of specific receptors. When mice have less POMC, it raises their pain threshold, increases their pain sensitivity and reduces their responsiveness to certain non-opioid painkillers while enhancing the effects of opioids, Pandit said.
Red hair is thought to provide an advantage in northern latitudes because it stimulates ultraviolet absorption – a critical step in the synthesis of vitamin D – but it is unclear whether it impairs pain and sensitivity to opioids. Redheads also offer benefits, Fisher said.
Although it’s unclear why it evolved, the link between red hair and pain is confirmed, “which is fascinating in itself,” Pandit said. It’s possible that doctors could eventually predict how a patient will respond to pain and painkillers by looking at their genes.
This article is for informational purposes only and is not intended to offer medical advice.
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