Cold receptors primarily react to temperatures ranging from 68 to 86˚F, while warm receptors are activated between 86˚F and 104˚F. At extreme temperatures—below 60˚F and beyond 113˚F—the temperature signal is accompanied by a sensation of pain. Weirdly, researchers have discovered that at temperatures greater than 113˚F, some cold receptors can also fire.
The majority of scientists support the theory that paradoxical cold is a malfunction of the thermoreceptor system. Evidence suggests that pain receptors that respond to potentially harmful heat levels coexist on the same sensory fibers as cold thermoreceptors, says Lynette Jones, a senior research scientist at MIT. So when the nerve fiber sends a signal to the brain, it can sometimes be misinterpreted as a sensation of extreme cold. Paradoxical cold is the “strange operation of a system under unusual stimulation conditions,” she says… Read more