Bradycardia during face cooling in man may be produced by selective brain cooling

907, 1979.-In human subjects, bradycardia was produced by immersing the subjects ’ faces in water at 15OC when they were hyperthermic. When they were hypothermic, the same face cooling produced tachycardia. It is suggested that the difference in cardiac response originates in selective brain cool-ing during hyperthermia, by venous return from the face to the brain, via ophthalmic veins. immersion; cold DIVING BRADYCARDIA was described for the first time by J. P. Bert in 1870 in the duck (2). This phenomenon was shown to exist in all species and has been extensively studied in man (1, 6, 7, 9, 11-13, 15, 16). Diving brady-cardia is considered to be a vagal reflex. It was shown to originate both in face immersion and in apnea (7). It is likely that the stimulus for bradycardia is face coolin