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Hypothermia & Hyperthermia

First, a bit of Greek:





below, under


above, over


warmth, heat


So, somebody who is hyperthermic has a body temperature which is too high! They have heatstroke!
Equally hypothermia is a body temperature which is too low.


is by definition a body temperature below 35°C (normal is 37°C)

  1. Causes

    • exposure

    • immersion in cold water....

  2. Types:

    • Acute or immersion hypothermia occurs when a person loses heat very rapidly, for example by falling into cold water.

    • Exhaustion hypothermia occurs when a persons is so tired the body can no longer generate heat.

    • Chronic hypothermia affects mainly the elderly or people sleeping rough.

  3. Stages: mild

    • shivering,

    • feeling cold,

    • low energy,

    • discomfort at higher temperatures than normal, or

    • cold, pale skin.


    • violent, uncontrollable shivering,

    • being unable to think or pay attention,

    • confusion (some people don't realise they are affected),

    • loss of judgement and reasoning,

    • difficulty moving around or stumbling (weakness),

    • feeling afraid,

    • memory loss,

    • fumbling hands and loss of coordination,

    • drowsiness,

    • slurred speech,

    • listlessness and indifference, or

    • slow, shallow breathing and a weak pulse.


    • loss of control of hands, feet, and limbs,

    • uncontrollable shivering that suddenly stops,

    • unconsciousness,

    • shallow or no breathing,

    • weak, irregular or no pulse,

    • stiff muscles, and

    • dilated pupils.

  4. Treatment:

    • hypothermia is a potentially life threatening condition. So if in doubt call medical help!

    • what you can do for mild hypothermia or before help arrives:

      • Get the person out of the water, or somewhere warm, as soon as possible.

      • Once sheltered, gently remove any wet clothing and dry the person.

      • Wrap them in blankets, towels, coats, exposure bags... (whatever you have), protecting the head and torso first.

      • Your own body heat can help someone with hypothermia. Hug them gently.

      • Increase activity if possible, but not to the point where sweating occurs, as that cools the skin down again.

      • If possible, give the person warm drinks (but not alcohol) or high energy foods, such as chocolate, to help warm them up. (Only if they are concious and able to swallow safely)

      • Once body temperature has increased, keep the person warm and dry.

    • do NOT:

      • Don't apply direct heat (hot water or a heating pad, for example) to the arms and legs, as this forces cold blood back to the major organs, making the condition worse.

      • Don't give the person alcohol to drink, as this will decrease the body's ability to retain heat.

      • Don't rub or massage the person’s skin, as this can cause the blood vessels to widen and decrease the body’s ability to retain heat. In severe cases of hypothermia there is also a risk of heart attack.

    • Severe hypothermia needs urgent medical treatment in hospital. Shivering is a good guide to how severe the hypothermia is. If the person can stop shivering of their own accord, hypothermia is mild, but if they cannot stop shivering, it is moderate to severe.

    • As the body temperature decreases further, shivering will stop completely. The heart rate will slow and a person will gradually lose consciousness. When unconscious, a person will not appear to have a pulse or be breathing. Emergency assistance should be sought immediately and CPR provided while the person is warmed. CPR is an emergency procedure, consisting of mouth-to-mouth resuscitation and chest compression.

  5. Prevention is better than cure!!! so when going out:

    • dress appropriately (dress for immersion)

    • carry a spare set of warm clothes and a warm drink

    • don't go alone

    • carry means of communication (e.g.: whistle, mobile phone, VHF, EPIRB...)

    • leave a float plan with a responsible person

Hyperthermia (heat / sunstroke):

I will only write very shortly about this as this will rarely happen in our latitude:

  • Causes: prolonged exercise in a hot environment, the body has lost too much water and many electrolytes.

  • Treatment: get in a cooler environment (shade...), drink water or electrolyte drink. If unconcious, seek medical help.

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