What is the core body temperature cutoff for hypothermia in the general population, including adults and children?

Hypothermia Temperature Cutoff

Hypothermia is defined as a core body temperature below 35°C (95°F) in the general population, including both adults and children. 1

Temperature Classification

The 2024 American Heart Association and American Red Cross guidelines provide the most current and authoritative staging system for hypothermia:

Cold Stress: 35-37°C

• Patients remain alert and may be shivering
• Not technically hypothermia, but represents the transition zone where individuals are "cold stressed"
• Passive rewarming is often adequate in healthy people 1

Mild Hypothermia: 32-35°C

• Altered level of responsiveness with shivering present
• Requires both passive and active rewarming methods
• Patients should seek additional medical care 1

Moderate Hypothermia: 28-32°C

• Decreased level of responsiveness (responding only to loud voice or pain)
• Shivering may or may not be present
• This is a medical emergency requiring activation of emergency response system 1

Severe Hypothermia: <28°C

• Unresponsive, may appear lifeless
• Cessation of shivering
• Slow heart rate and breathing
• High risk for cardiac arrhythmias and cardiac arrest 1

Profound Hypothermia: <24°C

• Represents the most extreme form of hypothermia
• Extremely high mortality risk 1

Critical Clinical Considerations

The 35°C cutoff is universally accepted across multiple high-quality guidelines from 2024, including the American Heart Association/American Red Cross 1 and research literature 2, 3, 4, 5. This represents the point where core body temperature drops below the normal physiologic range near 37°C and endogenous temperature control mechanisms fail to maintain homeostasis. 1

Important Caveats:

• Core temperature measurement is essential - superficial measurements (oral, tympanic, skin) are unreliable and can miss the diagnosis 1
• Core temperature should be measured via bladder, esophageal, or intravascular routes when available 1
• Clinical presentation may not match temperature severity - a rare case report documented a patient with severe hypothermia (25.1°C) who remained alert and communicative, emphasizing that diagnosis must be based on measured core temperature, not clinical symptoms alone 3
• Standard thermometers may not read low enough; low-reading thermometers are required for accurate diagnosis 1

Special Population Note:

These recommendations apply to children and adults but are not applicable to infants <60 days of age, who require different temperature thresholds and management 1.