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A cold shock response is a series of cardio-respiratory responses caused by a sudden immersion in cold water which might cause death, such as falling through thin ice. The immediate shock of the cold causes involuntary inhalation which, if underwater, can result in drowning.
The cold water can also cause a heart attack due to vasoconstriction; the heart has to work harder to pump the same volume of blood throughout the body. Inhalation of water (and thus drowning) may result from hyperventilation.
Hypothermia from exposure to cold water is not as sudden as it is often believed. A person who survives the initial minute of trauma (after falling into icy water) can survive for at least 30 minutes provided he/she doesn’t drown.
However, the ability to perform useful work (for example to save oneself) declines after 10 minutes as the body protectively cuts off blood flow to non-essential muscles. 1
Hypothermia occurs when the body can no longer sustain normal core temperature by vasoconstriction, shivering and muscle contraction. While shivering, the body is unable to maintain its core temperature; when the body core temperature falls below 35˚C, the syndrome of hypothermia occurs.2
Dr. Kamal Saad
Paediatrician
