In reply to Herdwickmatt: From the nhs website:
The symptoms of hypothermia depend on how cold the environment is and how long you are exposed for.
Severe hypothermia needs urgent medical treatment in hospital. Shivering is a good guide to how severe the condition is. If the person can stop shivering on their own, the hypothermia is mild, but if they cannot stop shivering, it is moderate to severe.
In mild cases, symptoms include:
shivering,
feeling cold,
low energy,
discomfort at higher temperatures than normal, or
cold, pale skin.
The symptoms of moderate hypothermia include:
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.
The symptoms of severe hypothermia include:
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.
Babies with hypothermia may look healthy but their skin will feel cold. They may also be limp, unusually quiet and refuse to feed.
Although hypothermia is defined as occuring when the body temperature drops below 35°C (95°F), mild hypothermia can start at higher body temperatures.