Variable profile of individual heart rate responses to cold water immersion apnea in healthy late adolescent men.

Holding breath combined with immersion of face in cool water induces diving reflex consisting in bradycardia, peripheral vasoconstriction, and preferential redistribution of blood to the vital organs. The individual responses are variable, highly expressed in young children to weaken with age. Detailed assessment of the cardiac response to diving in late adolescents who are mostly prone to unexpected diving experiments and related complications are of practical importance.