In an experiment, 10 brunettes and 10 redheads were given an anesthetic and were subjected to electrical shocks. The readheads required an average of 20% more anesthetic to become too numb to feel the shocks. This test was part of a 2002 study in the University of Louisville. According to the test’s findings, anesthesiologists should consider using more anesthetic when before performing surgery on a redhead. 

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