Hypothermia develops when the body temperature falls below 35°C (95°F). The effects vary depending on the speed of the onset and the level to which the body temperature falls. Moderate hypothermia can usually be completely reversed.

Severe hypothermia – when the core body temperature falls below 30°C (86°F) – is often, but not always fatal. However, no matter how low the body temperature is, it is always worth persisting with life-saving procedures until a doctor arrives to assess the casualty.

Recognition features

There may be:

  • shivering and pale, cold, dry skin
  • disorientation, apathy or irrational behaviour; occasionally belligerence
  • impaired consciousness or lethargy
  • slow and shallow breathing
  • slow and weakening pulse
  • in extreme cases the heart may stop.


Make sure that they are dry and sheltered from the wind, prevent further heat loss with blankets and, if conscious, give them a warm drink. Dial 999 or 112.

Related topics

Please note:

These hints are no substitute for thorough knowledge of first aid! St John Ambulance holds first aid courses throughout the country.

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