Although the distinctions among mild, moderate, and severe hypothermia are not often clear, a somewhat constant sequence of events occurs as core body temperatures continue to decline.
- At temperatures below 95 F (35 C), shivering is seen. Heart rate, breathing rate, and blood pressure increase.
- As the temperature drops further, pulse, breathing rate, and blood pressure all decrease. People may experience some clumsiness, apathy, confusion, and slurred speech.
- As core temperature drops lower than 89.9 F (32.2 C), shivering stops and oxygen consumption begins to drop. The victim may be in a stupor. The heart rhythm may become irregular.
- At temperatures below 82.4 F (28 C), reflexes are lost and cardiac output continues to fall. The risk of dangerously irregular heart rhythms increases, and brain activity is seriously slowed. The pupils are dilated, and the victim appears comatose or dead.
Medically Reviewed by a Doctor on 3/26/2015
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