The signs and symptoms of hypothermia are quite variable from one person to the next, even at the same body core temperature.
You are more likely to spot these signs and symptoms in other people than in yourself. In your group, you must look out for each other.
Some people like to divide up the progression of hypothermia into a series of stages and include within these stages easily recognisable signs and symptoms.
Stages of Hypothermia
Given that we are interested in halting and reversing any drop in temperature below our normal body core temperature we can use the following categorisation to give an indication of the severity of the case:
Mild hypothermia - core temp 37 to 35 deg Celsius (98.6 to 95.0 deg Fahrenheit);
Moderate hypothermia - core temp 35 to 33 deg Celsius (95.0 to 91.4 deg Fahrenheit);
Severe hypothermia - core temp 33 to 28 deg Celsius (91.4 to 82.4 deg Fahrenheit);
Deep hypothermia - core temp below 28 deg Celsius (82.4 deg Fahrenheit).
The pitfall with a categorisation based on body core temperature is that it's impossible to monitor internal body temperatures in the field.
A drop in core temperature will affect every part of your body's system, however, so we must look for the signs and symptoms of these changes:
Mild Hypothermia
An early sign of being too cold is shivering. On its own it doesn't necessarily signify hypothermia but it is a good early warning sign of the possibility. When your body detects it is starting to cool down below its normal temperature, it fairly quickly starts to shiver. Shivering increases your metabolic heat production to a level between two- and six-times that of your normal, resting rate. This has a short term warming benefit on your body but it reduces energy stores in your body. In the long term, this energy depletion adds to your deterioration by contributing to eventual exhaustion. If you or someone else is shivering, do something to warm up!
Another relatively early sign can be cold, stiff and/or white hands or feet. This is due to a reduction in blood supply to the area. This is one of your body's reactions to cold, intended to keep heat in your body's core. If your hands are white, cold or stiff it is a warning sign that your whole body is too cold. Again, do something to warm up!
Hypothermia progressively reduces mental function, the early signs of which are often missed. The first signs are mood changes, irritability and/or social withdrawal. This is really important but hard to spot in a group.
Even mild hypothermia can reduce your ability to look after yourself or your companions. Studies have shown even mild core cooling to temperatures in the range 34 deg Celsius (93 deg Fahrenheit) to 36 deg Celsius (97 deg Fahrenheit) will impair mental function. Decreased mental function translates into poor decision making, indecision, irrational behaviour, confusion and forgetfulness - all dangerous failings in the great outdoors.
Moderate Hypothermia
As the victim's body core temperature continues to drop, their mental function and physical coordination will be further reduced. Weakness, stumbling and repeated falling are typical. A good way of grouping some of this increased clumsiness and uncoordinated behaviour is remembering them as "the umbles", characterised by
Grumbles
Mumbles
Fumbles
Stumbles
Tumbles
Severe Hypothermia
As they continue to cool, the hypothermia victim will range from being lethargic to losing consciousness to comatose. Their lips and possibly fingers will be blue. Shivering is likely to have stopped as they run out of energy. Their temperature will drop further as the heat generated from shivering ceases. Muscles can become stiff. As their temperature drops their pulse will slow and weaken, blood pressure will drop and their breathing rate will slow. It may be impossible to feel a pulse.
Deep Hypothermia
The casualty may appear dead and indeed they might be - cardiac arrest often occurs with a body core temperature between 28 deg Celsius (82.4 deg Fahrenheit) and 25 deg Celsius (77 deg Fahrenheit).
Even if the casualty appears dead, however, it may be because vital signs are impossible to discern in the field. The lowest recorded core temperature from which someone has been successfully resuscitated is 13.7 deg Celsius (56.7 deg Fahrenheit). There is an old adage "a person is not dead until they are warm and dead."
You are more likely to spot these signs and symptoms in other people than in yourself. In your group, you must look out for each other.
Some people like to divide up the progression of hypothermia into a series of stages and include within these stages easily recognisable signs and symptoms.
Stages of Hypothermia
Given that we are interested in halting and reversing any drop in temperature below our normal body core temperature we can use the following categorisation to give an indication of the severity of the case:
Mild hypothermia - core temp 37 to 35 deg Celsius (98.6 to 95.0 deg Fahrenheit);
Moderate hypothermia - core temp 35 to 33 deg Celsius (95.0 to 91.4 deg Fahrenheit);
Severe hypothermia - core temp 33 to 28 deg Celsius (91.4 to 82.4 deg Fahrenheit);
Deep hypothermia - core temp below 28 deg Celsius (82.4 deg Fahrenheit).
The pitfall with a categorisation based on body core temperature is that it's impossible to monitor internal body temperatures in the field.
A drop in core temperature will affect every part of your body's system, however, so we must look for the signs and symptoms of these changes:
Mild Hypothermia
An early sign of being too cold is shivering. On its own it doesn't necessarily signify hypothermia but it is a good early warning sign of the possibility. When your body detects it is starting to cool down below its normal temperature, it fairly quickly starts to shiver. Shivering increases your metabolic heat production to a level between two- and six-times that of your normal, resting rate. This has a short term warming benefit on your body but it reduces energy stores in your body. In the long term, this energy depletion adds to your deterioration by contributing to eventual exhaustion. If you or someone else is shivering, do something to warm up!
Another relatively early sign can be cold, stiff and/or white hands or feet. This is due to a reduction in blood supply to the area. This is one of your body's reactions to cold, intended to keep heat in your body's core. If your hands are white, cold or stiff it is a warning sign that your whole body is too cold. Again, do something to warm up!
Hypothermia progressively reduces mental function, the early signs of which are often missed. The first signs are mood changes, irritability and/or social withdrawal. This is really important but hard to spot in a group.
Even mild hypothermia can reduce your ability to look after yourself or your companions. Studies have shown even mild core cooling to temperatures in the range 34 deg Celsius (93 deg Fahrenheit) to 36 deg Celsius (97 deg Fahrenheit) will impair mental function. Decreased mental function translates into poor decision making, indecision, irrational behaviour, confusion and forgetfulness - all dangerous failings in the great outdoors.
Moderate Hypothermia
As the victim's body core temperature continues to drop, their mental function and physical coordination will be further reduced. Weakness, stumbling and repeated falling are typical. A good way of grouping some of this increased clumsiness and uncoordinated behaviour is remembering them as "the umbles", characterised by
Grumbles
Mumbles
Fumbles
Stumbles
Tumbles
Severe Hypothermia
As they continue to cool, the hypothermia victim will range from being lethargic to losing consciousness to comatose. Their lips and possibly fingers will be blue. Shivering is likely to have stopped as they run out of energy. Their temperature will drop further as the heat generated from shivering ceases. Muscles can become stiff. As their temperature drops their pulse will slow and weaken, blood pressure will drop and their breathing rate will slow. It may be impossible to feel a pulse.
Deep Hypothermia
The casualty may appear dead and indeed they might be - cardiac arrest often occurs with a body core temperature between 28 deg Celsius (82.4 deg Fahrenheit) and 25 deg Celsius (77 deg Fahrenheit).
Even if the casualty appears dead, however, it may be because vital signs are impossible to discern in the field. The lowest recorded core temperature from which someone has been successfully resuscitated is 13.7 deg Celsius (56.7 deg Fahrenheit). There is an old adage "a person is not dead until they are warm and dead."
SHARE
