Tag Archives: Cold

We Die Alone


“When one’s body is worn by a long effort at the limit of its strength, and especially when its function is dulled by cold, one’s mind loses first all of its sharp appreciation of time. Incidents which are really quiet separate become blended together; the present and the immediate past are not distinct, but are all part of a vaguely defined present, of physical misery. In a person of strong character, hope for the future remains separate long after the past and present are confused. It is when the future loses its clarity too, and hope begins to fade, that death is not far away.”

-We Die Alone

We Die Alone is required reading prior to the OBXi Marine Corps Black Sea Rotational Force Training Module. AMZ

A good introduction to the fundamentals of escape and evasion is We Die Alone, A WWII Epic of Escape and Endurance by David Howarth. The book is about a nearly nine week ordeal by Jan Baalsrud, a Norwegian dissident who volunteers to infiltrate occupied Norway during WWII.

The story begins in the spring of 1943, with Norway occupied by the Nazis and the Allies seeking to disrupt German coastal defenses in the North. Baalsrud, and three other covert agents, smuggle themselves into their homeland using a small fishing boat crewed by eight Norwegian sailors. They are planning to spend the Norwegian summer recruiting and training resistance fighters and launching a surprise attack on a critical German air base. But Baalsrud and the crew are betrayed shortly after landfall, and a quick fight leaves him alone and trapped on a freezing island above the Arctic Circle. He is poorly clothed (one foot is entirely bare), has an initial head start of only a few hundred yards on his Nazi pursuers, and leaves a trail of blood as he crosses the snow.

Highlights of his ordeal include surviving three days wandering non-stop in the far north completely snow-blind; amputating nine of his own toes with no anesthetic and a pocket knife; and being literally buried under four feet of snow and ice for a week and – ironically – surviving the blizzard which raged above it.

The “hero” of the book turns out to be the various people he meets along the way and who volunteer to smuggle him across the frontier into Sweden at great cost and risk to themselves and their families.

The story has many lessons in the vignettes on how he survives and avoids capture:

  • Don’t give up. It bears repeating because it the crux of the entire story: “When one’s body is worn by a long effort at the limit of its strength, and especially when its function is dulled by cold, one’s mind loses first all of its sharp appreciation of time. Incidents which are really quiet separate become blended together; the present and the immediate past are not distinct, but are all part of a vaguely defined present of physical misery. In a person of strong character, hope for the future remains separate long after the past and present are confused. It is when the future loses its clarity too, and hope begins to fade, that death is not far away.” Don’t give up. This passage has application in all facets of life.
  • Survival and evasion eventually requires reliance on others. The more extreme the environment, the sooner you will need assistance. During his journey, Jan would not have survived without the help of many courageous villagers in the isolated, yet very connected and tribal, northern Norway. It will be critical that people sympathize, and trust the person they come in contact with. Baalsrud was very careful about the information he shared and how he presented it it. By doing so, he reduced the anxiety of those he came in contact with, establishing rapport and trust as a priority. All formal US military SERE courses include a local support or “supporting insurgent” component during training because of this.
  • The more you are forced to rely on others, the more operational risk you will have. This is a no brainer and thus the balancing act. Remember, relying on others may also mean relying on their resources (i.e., shelter, food, clothing, vehicles, boats, etc.) without the “others” knowledge. Of course, by doing so, it may create the perception that you are a common criminal and no quarter will be given if discovered. The evader must always balance the risks associated with using local resources without permission with revealing him/herself to a potential friendly asset. Baalsrud’s crew revealed their intentions right off the bat to the wrong person and paid for it with their lives quickly.
  • The more you know, the less you need (at least in the short term). Baalsrud was on the run with not much more than what he was wearing and a boot on one foot. REI commandos take heed! This is said tongue in cheek, of course, because there are many unanswered questions in the book like what type of fire starter Baalsrud uses, as well as his fuel, food and specific items of clothing and shelter he is provided from the various people he came in contact with.

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To Do Today:


Hypothermia, frostbite, and trench/immersion foot are the most popular cold injuries for students during the winter. Photokeratitis (snow blindness) will be covered sometime later as it usually occurs during sunny summer months. Please make sure to read the notes on carbon monoxide poisoning at the end of the post.


A common belief that extremely cold temperatures are needed for hypothermia to occur is not true as most cases occur when the temperature is between 30 and 50 degrees Fahrenheit.

Simply, hypothermia occurs when heat loss from the body exceeds the body’s ability to produce heat. Contributing factors include:

  • Air temperature
  • Ambient temperature
  • Wind chill
  • Wet clothing
  • Cold water immersion
  • Improper clothing.
  • Exhaustion.
  • Alcohol intoxication, nicotine and drugs such as barbiturates and tranquilizers.
  • Injuries. Those causing immobility or major bleeding, major burn and head trauma.

Signs and symptoms

The number one sign to look for is altered mental status; that is, the brain is literally getting cold. These signs might include confusion, slurred speech, strange behavior, irritability, impaired judgment, hallucinations, or fatigue.

As hypothermia worsens, victims will lose consciousness and eventually slip into a coma.

Shivering. Remember that shivering is a major way the body tries to warm itself early on, as it first begins to get cold. Shivering stops for two reasons:

  • The body has warmed back up to a normal temperature range.
  • The body has continued to cool. Below 95F shivering begins to decrease and by 90F it ceases completely.

Obviously, continued cooling is bad. So if a victim with whom you are working, who was shivering, stops shivering, you must determine if that is because he has warmed up or continued to cool.

A victim with severe hypothermia may actually appear to be quite dead, without breathing or a pulse. However, people who have been found this way have been successfully “brought back to life” with no permanent damage. The body of those who expire from hypothermia will exhibit a temporary warmth of the skin. So remember, you are not dead until you are warm and dead.

Prevention. Prevention is always better (and much easier) than treatment.

  • Cold weather clothing must be properly warm and cared for.
  • Keep your clothing as dry as possible.
  • If your feet are cold, wear a hat. Up to 80% of the body’s heat can escape from the head.
  • Avoid dehydration. Drink 6 – 8 quarts per day.
  • Eat adequately.
  • Avoid extreme fatigue and exhaustion.
  • Increase levels of activity as the temperature drops. Do not remain stationary when the temperature is very low. If the tactical situation does not permit moving about, perform isometric exercises of successive muscles.
  • Use the buddy system to check each other for signs/symptoms of hypothermia.

Treatment of Hypothermia

  • Make the diagnosis.
  • Prevent further heat loss.
  • Remove the victim from the environment (i.e., into a shelter).
  • Insulate the victim.
  • Rewarm the victim by zipping two sleeping bags together. Pre-warm the bag by using the body heat of another. Place the victim in the bag with two stripped companions inside the bags on both sides of the victim (insert dirty jokes and snide remarks here).
  • Medevac if possible.

Other Points to Remember

  • Fluids. If the victim is mildly hypothermic, give hot/wets.
  • If worse than mild, give him/her nothing by mouth.
  • Avoid, if possible, excessive movement of the victim, as his/her heart may actually stop beating if it is jarred.
  • Major Wounds. Apply first aid to major wounds first, before attempting to re-warm the victim. Re-warming a victim who has bled to death does little good.
  • Never give alcohol to hypothermia victims.
  • Even after you have started re-warming a victim, he/she must be constantly monitored. Don’t forget about the victim.


Frostbite is the actual freezing of tissues. When in a survival/SERE situation, rewarming a severe frostbitten area may not help. It is best to be vigilant of your situation prior to showing signs of frostbite as frostbite is a somewhat preventable injury, even in a desperate situation. It is critical, once frostbite has occurred, that you seek medical attention.

  • Dress in layers. Keep comfortably cool. If you begin to become uncomfortable, add layers.
  • Keep clothes dry. If clothing (especially socks and gloves) become wet, change them. This may mean you have to change sock 4-5 times a day.
  • Dress properly. If the wind is blowing, wear the correct protective layer.
  • Avoid dehydration. When dehydrated, the amount of blood available to warm your fingers and toes goes down, increasing the risk of frostbite.
  • Try to avoid starvation. Remember – food is fuel – and the body uses that fuel to make heat.

Signs and Symptoms

  • Ears, nose, fingers and toes are affected first.
  • Areas will feel cold and may tingle leading to….
  • Numbness which progresses to…
  • Waxy appearance with skin stiff and unable to glide freely over a joint.


  • Frostbite is classified into three different degrees: Frosting, Superficial Frostbite, and Deep Frostbite.
  • Frosting will revert to normal after using the technique of body heat rewarming. Hold the affected area, skin to skin for 15 minutes. Rewarm face, nose, and ears with hands. Rewarm hands in armpits, groin or belly. Rewarm feet with mountain buddy’s armpits or belly.
  • If affected area cannot be rewarmed in 15 minutes, Superficial Frostbite or Deep Frostbite is suspected. Do not attempt to further rewarm. Splint the affected area. Protect the affected area from further injury. Medevac as soon as possible. DO NOT RUB ANY COLD INJURY WITH SNOW. Do not massage the affected area. Do not rewarm with stove or fire: a burn injury may result. Loosen constricting clothing. Avoid tobacco products.

Any frostbite injury, regardless of severity, is treated the same – evacuate the casualty and re-warm in the rear. If not possible, find shelter and seek friendly indigenous medical care. If the tactical/survival situation prohibits evacuation, no consideration should be given to re-warming frostbite in the field. The reason is something-called freeze – thaw – re-freeze injury.

Freeze – Thaw – Re-freeze injury occurs when a frostbitten extremity is thawed out, then before it can heal (which takes weeks and maybe months) it freezes again. This has devastating effects and greatly worsens the initial injury.

In an extreme emergency it is better to walk out on a frostbitten foot than to warm it up and then have it freeze again. Also:

  • Treat frozen extremities as fractures – carefully pad and splint.
  • Treat frozen feet as litter cases.
  • Prevent further freezing injury.
  • Do not forget about hypothermia. Keep the victim warm and dry.

Once in the rear, a frostbitten extremity is re-warmed in a water bath, with the temperature maintained at 101F – 108F.


Trench foot / immersion foot is a cold-wet injury to the feet or hands from prolonged (generally 7 – 10 hours) exposure to water at temperatures above freezing.

Signs and Symptoms. The major symptom will be pain. Trench foot is an extremely painful injury. Trench foot and frostbite are often very difficult to tell apart just from looking at it. Often they may both be present at the same time. Signs include:

  • Red and purple mottled skin.
  • Patches of white skin.
  • Very wrinkled skin.
  • Severe cases may leave gangrene and blisters.
  • Swelling.
  • Lowered or even absent pulse.
  • Trench foot is classified from mild to severe.

Prevention. Avoiding trench foot/immersion foot is aimed simply at preventing cold, wet and immobile feet (or hands).

  • Keep feet warm and dry.
  • Change socks at least once a day. Let your feet dry briefly during the change, and wipe out the inside of the boot. Sock changes may be required more often.
  • Exercise. Constant exercising of the feet whenever the body is otherwise immobile will help the blood flow.

Treatment. All cases of trench foot must be evacuated. It cannot be treated effectively in the field.

While awaiting evacuation:

  • The feet should be dried, warmed, and elevated.
  • The pain is often severe, even though the injury may appear mild; it may require medication such as morphine.
  • In the rear, the healing of trench foot usually takes at least two months, and may take almost a year. Severe cases may require amputation. Trench foot is not to be taken lightly.



Cold environments probably mean you will spend time inside some sort of shelter and have some sort of fire or other heat source. It is critical you have airflow and fresh air built into your setup. Carbon Monoxide is no joke.

Carbon Monoxide (CO) is a heavy, odorless, colorless, tasteless gas resulting from incomplete combustion of fossil fuels. CO kills through asphyxia even in the presence of adequate oxygen, because oxygen-transporting hemoglobin has a 210 times greater affinity for CO than for oxygen. What this means is that CO replaces and takes the place of the oxygen in the body causing Carbon Monoxide poisoning.

Signs/Symptoms. The signs and symptoms depend on the amount of CO the victim has inhaled. In mild cases, the victim may have only dizziness, headache, and confusion; severe cases can cause a deep coma. Sudden respiratory arrest may occur. The classic sign of CO poisoning is cherry-red lip color, but this is usually a very late and severe sign, actually the skin is normally found to be pale or blue.

CO poisoning should be suspected whenever a person in a poorly ventilated area suddenly collapses. Recognizing this condition may be difficult when all members of the party are affected.

Treatment. The first step is to immediately remove the victim from the contaminated area.

  • Victims with mild CO poisoning who have not lost consciousness need fresh air and light duty for a minimum of four hours. If oxygen is available administer it. More severely affected victims may require rescue breathing.
  • Fortunately, the lungs excrete CO within a few hours.

Prevention. Ensure there is adequate ventilation when utilizing a fire or other chemical/mechanical heat source near your shelter.



To Do Today:

Anyone swimming in Outer Banks waters during the winter will be exposed to conditions that will challenge your very soul to cope with cold and wet. The Atlantic is a cruel master but it’s also an excellent environment to build physical and mental skills to understand the processes, and limits, of your body and mind.


First, blood vessels at the skin surface close down, or constrict. This does two things:

  • Less blood goes near the surface of the body so that less heat is lost to the outside.
  • More blood goes to the “core” or the center of the body to keep the brain, heart,lungs, liver, and kidneys warm. This means fingers and toes tend to get cold and are more susceptible to frostbite and injury.

The next step is shivering. Shivering is reflexive regular muscular contractions and causes internal heat production. Shivering can only last for a short time before exhaustion occurs. With shivering you will either warm up, as usually occurs when you build a fire or find shelter, or continue to get colder and start to become hypothermic.

The biggest statistical danger for injury from the cold comes from frostbite and other medical conditions like trench foot but hypothermia is the number one killer of people in a survival situation.

How cold is cold?

Your body temperature right now is somewhere between 96.5F and 100.4F degrees, 98.7F being the norm and regulating that temperature between this fairly narrow range is critical. (When we exercise, the body temperature can quickly rise to about 102F, and can even go to 104F with few ill effects if the conditions are temporary.)

The body regulates temperature in a number of different ways. In heat, its through sweating, sending blood to the skin etc. In the cold, the opposite happens – you shift blood away from the skin, you shiver and release hormones that help keep the temperature up. The body is naturally insulated by skin, muscle and fat, and it’s no coincidence that a lean athlete with low body fat is likely to get colder sooner.

A drop in core body temperature is rare on land, even in very cold conditions, provided you are not forced into prolonged exposure and cannot find shelter. The main factor predicting body temperature is metabolic rate. If you are moving, your body  temperature will rise, regardless of how cold it is…up to a point. Your body temperature will only fall if you lose heat faster than you produce it. When you are in cold conditions, the fact is that you’re usually:

  • Prepared. You are wearing, or have access to, warm clothing and waterproof equipment. You are not likely to lose heat too rapidly and your body temperature is a function of heat production. In this case, cold is a function of perception and you can regulate your body temperature.
  • Not Prepared. You are dressed inadequately, wet or not waterproof, and possibly with skin exposed. Or, you have emerged from the sea/river/snow having just experienced an unforeseen event. In this case, you’ll feel cold immediately or within minutes depending on the temperature and will be unlikely to do anything other than attempt to build a fire or find shelter on the spot to stay alive or not lose body parts.

The point is, the sensation cold, mediated through your skin over time, dependent on temperature, precedes the possibility of hypothermia. Provided you have free-will (and choose to exercise it), you will be able to get warm as long as you have the resources to get dry and can make/find shelter. If you are unlucky enough to be forced to spend a good deal of time exposed to the cold (boat accident, injury on the run/ride, getting lost, evasion, plane crash, etc.), your physiology is going to be challenged. Remember, the more you know about using your environment, the fewer resources you may need.

Wet Vs. Dry

There is a big difference between cold air and cold water exposure. The key difference is that heat losses in water, or when you are wet, are much greater than when dry. You are far less likely to develop hypothermia on land because you can typically “get dry” within a period of time that will prevent lower core temperature. But because water conducts heat about 25 times better than air, especially when it is moving across your skin as in a river or ocean, you are going to have a bad day unless you can get dry quickly.

Perhaps the the most surprising fact about cold water physiology, is that your body has heat stores to prevent hypothermia in water for about 20-30 minutes, no matter how cold the water is. In other words, it is not possible to get so cold that you are in danger unless you are in the water for more than about 30 minutes. The graph below shows this:

Cold Water Exposure

From this graph, you can see that even at water temperatures of 32F degrees, 30 minutes falls within the marginal danger zone, not the lethal zone. Many would probably survive for close to an hour – this is demonstrated by shipwreck victims, who have survived freezing water for this long.

Three critical phases of cold-water immersion:

First 5 minutes – immediate shock You will experience the ‘gasp reflex,’ which is the sudden gasp of air as a result of the shock. You will be unable to hold your breath, and hypertension and increased cardiac output will result. Most casualties in this phase are due to drowning or a heart attack, even before hypothermia can begin to set in.

Next 15 minutes – inhalation of water You won’t be able to keep afloat or swim, and your ability to grasp or climb into/onto things will diminish. Typically, most casualties in this phase are due to drowning from excessive inhalation of water.

30 minutes – onset of hypothermia 98.7° C is considered normal body core temperature. When your core temperature drops to 95.1° C, muscle tone starts to become affected. Most people have experienced this feeling of tension in their back and neck when they’ve become chilled.

The cold-shock response

One of the first things experienced when submerging in cold water is “cold-shock response.” This is characterized by an uncontrollable gasp for air, followed by hyperventilation – rapid breathing. This response is one of the most likely causes of death in most cold-water immersions such as when one falls out of a boat into icy water. If the timing of your “gasp” is wrong, you’ll take in a lungful of water, and one or two gasps while underwater is all it takes to drown.

Another big killer is a heart attack, which can result when the temperature of the blood returning to the heart is suddenly cooled – this can affect the electrical conduction within the heart, causing fibrillation.

Swimming in the cold

Once you’ve overcome cold-shock, the next thing to worry about is swimming. Hyperventilation doesn’t necessarily stop with the initial shock, cold water has a profound effect on the ability to swim in an efficient manner. Breathing goes up from about 16 breaths per minute to 75 breaths per minute within the first 20 seconds. It then stays up at 40 breaths per minute for the next few minutes. It is not difficult to see how that would affect your ability to swim, because your stroke rate would have to change substantially to allow you just to breathe.

The Titanic Problem

When muscle and the skin are cooled, the muscle becomes weaker. So cold water on the skin will make a powerful swimmer incapable of swimming, simply because his skin is cooled. There is evidence from studies that shows that the ability of the muscle to produce force is as much as 25% lower immediately after exposure to water at 10 degrees celsius – this would only drop in even colder water. Then we add to that the fact that as you get cold, your body’s natural response is to shiver. But when you shiver, your co-ordination is affected, making it even more difficult to swim.

This has profound implications on ability to swim. The character played by Leonardo DiCaprio could not swim to safety in the movie Titanic because of this physiological explanation – he simply could not swim; his skin and muscles were too cold to contract normally. The principle remains – a good swimmer in warm water will be an average swimmer in the cold. And a weak swimmer…Sayonara.

Adapting to cold shock

The good news is that humans are adaptable organisms, and just like we make adaptations to things like marathon training, we also make adaptations to stressors such as cold-water immersion. The data show that repeated (as few as six) exposure to cold water as short as three minutes in a 50F shower will attenuate the cold-shock response by as much as 20-30%. If you have even longer exposure to cold water in training, you can bring it down by 50%. That is obviously a significant reduction, and the implication is that swimming will be far easier if you are simply adapted to the cold.

The second important adaptation involves blood flow and heat loss. When at rest your muscle tissue actually acts as in insulator. This changes when you exercise because now you are pumping lots of blood to the working muscles, and it is the blood that transports heat around the body. Therefore when you start to swim in cold water you send more blood to the muscles, and all this does is increase your heat losses as now the blood, and the heat it contains, close to the surface of the body. Since water conducts heat very well, the heat from your body readily moves to the water, and the consequence of this is a decrease in core temperature even though you are producing some heat with your muscle contractions.

Decreases in shivering

Another big change that occurs with repeated cold-water exposure is the lowering of the “shivering threshold,” or the temperature at which we begin to shiver. The bonus of shivering is that we produce heat as our muscles are contracting, although involuntarily. The downside is that when trying to perform a complex movement such as swimming (or motor skills like tying a knot), shivering can really foul things up. If you can adapt by lowering the temperature at which you begin to shiver, the result will be swimming/working longer before being hampered by shaking limbs and uncontrolled movements.

Evidence for non-shivering thermogenesis?

There is evidence that humans can actually increase their core temperature either acutely or chronically in response to repeated cold-water exposures. The net effect of this response is that they can then remain in a cold environment for much longer before suffering any detrimental effects of the exposure, such as decreased nerve conduction velocity and then shivering (and a loss of coordination as a result of that shivering). Simply put, they have more heat in their bodies, and together with the other adaptations we mentioned above it means they reach a critically low temperature much later than someone who is not adapted to the cold.

The message here is that cold-water exposure is just like any other “stressor” or training stimulus. Our physiological response to these stimuli is to make adaptations that allow us to cope better, in this case is cold-water immersion.