Meredith Melnick, Time, December 10, 2010
As the authors of a recent study published in BMJ attest, society’s red-haired members don’t always get a fair shake. Hoary stereotypes, such as the idea that redheads are also hot heads, are mixed together with actual physiological differences–such as a heightened sensitivity to pain. Now science is getting a better understanding of redheaded physiology than ever before.
In numerical terms, people with red hair are a decided minority. They comprise just 2-6% of the population of the northern hemisphere and 1-2% worldwide. It’s genetics that make them such rare birds.
Operating room docs, for example, have long reported that redheads appear to need more anesthetic than others. The new study suggests that that observation is an accurate one–mostly. Those with the MC1R mutation are more sensitive to opiate pain killers–which means they’d actually need less–but less sensitive to other types, most notably lidocaine injections. One study which used heat-related pain as its litmus of overall sensitivity showed that redheads indeed felt things more acutely and unpleasantly, probably because the MC1R mutation releases a hormone that stimulates a brain receptor associated with pain regulation.
Redheads are also said–anecdotally at least–to be more susceptible to hernias. The study did not establish that conclusively, but it did find a tangential link between chromosome 16 and a condition called brittle cornea syndrome, the sufferers of which have a slightly elevated hernia risk.
Less substantiated by the study was the belief that people with red hair are more susceptible to hemorrhages. A survey of tonsillectomy patients found that about 7% of both red-haired and control patients experienced post-surgical bleeding. And in a study of the blood coagulation of 50 women, half of whom were redheads, there was no difference in clotting.