Redheads, anesthesia and hernias

Operating room doctors have long reported that redheads appear to need more anesthesia than others. A 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 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.