According to a study by Dr Edwin Liem of the University of Louisville in the US, people with natural red hair require more anaesthesia than people with other hair types. The results of the study not only have implications for redheads who require surgery, but may also give researchers a better understanding of how anaesthesia works in humans.
Dr Liem's study indicates that redheads need about 20% more anaesthesia than people with other hair colours. Scientists often look at a person's phenotype, or their overall physical, biochemical and physiological makeup, that is determined by genetics and the environment. "Red hair is the first visible human trait, or phenotype, that is linked to anaesthetic requirement," Dr Liem said.
Redheads have what is called a "dysfunctional melanocortin 1 receptor" on certain cells that give pigment to people's skin and hair. Dr Liem said he believes that dysfunction of this receptor triggers a feedback mechanism that increases release of the hormone which normally stimulates these cells. The importance of this mechanism is that the same hormone also stimulates a related brain receptor that increases pain sensitivity, he said.
"In a nutshell, redheads are likely to experience more pain from a given stimulus and therefore require more anaesthesia to alleviate that pain."
