A new study suggests people with naturally red hair need about 30 percent more anesthesia than patients
with other hair colors. The genetic quirk that makes red hair red may also make carrot-tops harder to knock out -- in the operating room. People with red hair need more anaesthesia to make them lose consciousness. Although anaesthetics have been in use for well over a century, we understand surprisingly little about how they really work. A study by doctors at the University of Louisville has come up with a new connection between hair colour and the amount of anaesthetic someone needs to 'put them under'.
A group of healthy women aged between 20 and 50 with natural bright red or dark hair were given the anaesthetic desflurane, and then monitored for reflex movements to painful stimuli. It took more anaesthetic to extinguish these pain responses in the redheads.
The researchers believe that the link between red hair and anaesthetics lies in the melanocortin system. Those with red hair have a specific variant of the melanocortin receptor in the cells that give hair and skin their pigment. This variant triggers the production of melanocortin which also stimulates a related brain receptor, involved in pain sensitivity. In other words, redheads are more sensitive to pain and need more anaesthetic to dull their pain responses. This study may shed new light on how anaesthesia works important, given there is a fine line between giving too little anaesthetic and too much.