What is Hypothermia?

Hypothermia, or exposure as it is frequently called, happens when the temperature of the core - the interior of the body containing the vital organs such as the heart, lungs and brain - falls below 35 degrees C. It is a dangerous condition and if the temperature continues to fall, unconsciousness, breathing and heart-failure leading to death will result.  Individuals vary considerably in their resistance to cold, but the young and the old are particularly vulnerable to hypothermia, as are those who fall into cold water which removes heat from the body thirty times more quickly than cold air.  The probability of hypothermia is therefore probably greater in water-based activities than on land.

Causes of Hypothermia

Hypothermia occurs when the body is exposed to cold, whether brought about by falling into water or the cold, wet windy conditions of the British hills.  The British Isles pose a far greater danger than the more predictable hard, dry cold of Alpine regions.  Wet destroys the insulation provided by clothing and the wind lowers the effective temperature drastically - the wind-chill effect.

The other critical factor in hypothermia is exhaustion.  The draining of the body's reserves of energy by the physical demands placed upon it is nearly always a major factor in hypothermia which occurs under expedition conditions.  Continuing the venture, or trying to increase the work rate to keep warm, only succeeds in draining away what little energy remains and makes the condition worse.

Signs and Symptoms

It is not always easy to distinguish between someone who is very cold, a frequent and common condition for all who engage in outdoor pursuits, and the first signs of hypothermia.

When conditions are really bad, members of a group must watch each other's condition and behaviour to detect the first signs of hypothermia.  The well-being of individuals may entirely depend on the observations of the rest of the group.  It is part of the nature of hypothermia that it cannot be recognised by the victim.  In its early stages, it can be difficult to diagnose and can creep up unawares and at other times it can be sudden and catastrophic.  The following signs and symptoms may occur, though not in any particular order:

  • Complaints of feeling cold, miserable and tired
  • Pale skin and shivering
  • Lack of interest in what is going on and a failure to understand simple questions and directions
  • Violent shivering ('the shakes')
  • Lack of muscular co-ordination, slurred speech and abnormality of vision
  • Irrational, aggressive or violent behaviour
  • Unusually cold skin to the touch
  • Shivering stopped, a slowing down of the pulse and breathing
  • Collapse, coma, death

Hypothermia is most likely to occur in exposed places where there is no shelter from the wind and where the wind blows strongly and relentlessly.  If the signs of hypothermia are detected at the very earliest stage, it may be possible to seek shelter or beat a hasty retreat while the potential victim can still function effectively.  Urgent action is required.  Sometimes hypothermia can affect a single member of a group while the rest are still fit.  This can occur when an individual is less fit than the rest of the party, is exhausted, has a medical condition, is particularly thin or is recovering from an illness such as 'flu.  The initial signs of hypothermia in a participant should ring an alarm for all the other members of the group who may themselves be not far removed from the hypothermic condition.

Dealing with Hypothermia

The first action is to find shelter from the wind in the lee of a wall, rock or ridge.  Further heat-loss must be prevented, the victim being covered with extra dry clothing and placed in a sleeping bag and then inside a bivvy bag.  Cold strikes up from the ground so insulation must be provided using a sleeping mat or anything else which can be improvised.  If the victim's clothing is wet and there is dry clothing available, the wet clothing should be replaced as quickly as possible, keeping heat-loss to a minimum.  If there is no dry clothing, the patient should be placed, wet clothing and all, into a bivvy bag and then into sleeping bag.  This will avoid the sleeping bag getting wet and losing its insulating qualities.

While the casualty is being insulated, shelter should be provided, either by pitching a tent or constructing a bivouac, and water boiled for a hot drink.  If the patient is conscious and able to swallow, hot sweet drinks will warm internally and replace lost energy.  This can be followed in due course by boiled sweets and chocolate bars which provide energy quickly in an easily absorbed form.

Warmth will be increased if the group huddles together and it may be possible to get another person into the sleeping bag or bivvy sack to keep the patient warm.

No attempt should be made to warm the victim’s skin by rubbing or using a hot water bottle as this may cause a surge of blood from the core to the surface with fatal results.  Do not give alcohol.

Normally recovery will take place of its own accord by slow re-warming in a matter of hours, or sometimes more quickly.

If the patient stops breathing, resuscitation should be carried out.  The pulse of a victim in the advanced stages of hypothermia may be so weak that it can hardly be detected and may only be found in the carotid artery in the neck.  No effort should be spared to detect any pulse as any attempt to administer cardiac massage while the heart is still beating, no matter how weakly, may have fatal results.  A casualty, especially one suffering from hypothermia, must not be presumed dead by anyone other than a doctor.  'Persons who are cold and dead must not be presumed dead until they are warm and dead!'

Unless hypothermia has been caught at an early stage, especially if collapse and unconsciousness have occurred, assistance must be sought to evacuate and treat the casualty as it requires the competence of those who are experienced and qualified in such treatment.  Hospitals, paramedics and mountain rescue teams have more sophisticated methods of re-warming and are capable of providing careful, gentle handling and horizontal carrying which are essential in advanced hypothermia.

In conclusion, hypothermia should never happen to those engaged in Award ventures during the Expedition season, whether on land or water, as participants will be carrying all the equipment required to prevent it food, warmth and heat in the form of a stove and fuel, insulation in extra clothing, sleeping bags and mats and the shelter of a tent.  Providing everyone in the party is alert to the insidious way in which hypothermia creeps upon its victims in cold, wet, windy conditions and all keep a constant watch on each other for the first symptoms of hypothermia, it should not pose a threat for, like the effects of sun and heat, it is more easily prevented than cured.