Temperature extremes, both high and low, ultimately factor into any survival situation. Excessive heat or cold can hamper operations on a good day and even become life threatening when things go bad. Keeping an eye out for extreme weather conditions and planning accordingly can ultimately be critical factors to both success and survival.

The sun is our lifeforce, but the dangers it presents seem equal to its benefits. Heat injuries include heat cramps, heat exhaustion and heat stroke, and these afflictions can occur even in modestly warm temperatures in the presence of excessive exertion. Yard work, military operations and outdoor professions like construction are notorious contributors. The first line of defense against a heat-related injury is always aggressive hydration.

Beat The Heat

Heat cramps, as the name implies, involve the painful cramping of major muscle groups. These spasms may manifest in your arms, legs, back or belly and can be extremely painful. The primary etiology of heat cramps involves electrolyte imbalances stemming from excessive loss through sweating combined with excessive exertion. Treatment is to retire to a shady spot to loosen clothes and cool off, along with aggressive fluid replenishment and the massaging of arms and legs to increase circulation.

Heat exhaustion represents the next phase of worsening heat injury and is characterized by headache, profuse sweating, nausea, vomiting, dizziness and peripheral tingling. In the case of heat exhaustion, core body temperature rises to between 99 and 104 degrees Fahrenheit. The causes of this disorder include dehydration, fatigue and electrolyte depletion. Treatment is the same as that for heat cramps plus evacuation to a cool location.

Heat stroke is profoundly dangerous. Heat stroke is a progression beyond heat exhaustion and is characterized by elevated temperature along with central nervous system dysfunction and, in later stages, an absence of sweating. The resulting organ damage can include brain damage, liver and kidney failure and blood-clotting anomalies.

The treatment of heat stroke is emergent. Remove your clothes, place ice in the groin and armpits, and administer IV fluids if possible. This condition should be treated as a medical emergency and the victim should be evacuated to proper medical treatment as soon as possible.

High-Temp Hazards

Unlike sleep deprivation and prolonged cold exposure, proper acclimatization to a hot environment can be remarkably effective. Acclimatization is a natural phenomenon and occurs for most people within five days of exposure to hot conditions. Ninety-five percent of healthy people will be fully acclimatized within 14 days. Acclimatization is lost in roughly the same period after removal from a hot environment.

Acclimatization results in increased sweat volumes at lower temperatures, a decreased loss of electrolytes in sweat, an increase in heat dissipation and subsequent lower core body temperature for a given environment and an overall decreased risk of heat injury.

Cool water is usually the best rehydration fluid and frequent drinking is the first line of defense against heat injury. If water is in short supply, it is wiser to drink as infrequently as the circumstances demand, but when you drink, try to drink your fill. Meals and snacks plus water are the best ways to retain proper electrolyte balances but under certain circumstances sports drinks can be an effective substitute.

Deadly Cold

Living in traditionally warm-weather climates does not necessarily make you immune to life-threatening, deep-freeze temperatures and threats. A few years back, an unexpected ice storm paralyzed an interstate bypass in Atlanta, Georgia, and stranded motorists in their cars for as much as a full day in freezing temperatures. The southern city did not have an emergency plan in place to deal with winter weather and subsequently was brought to a standstill for several days. Those without proper gear learned very quickly that preparing and stocking up for cold weather is a good idea for the vast majority of American citizens.

Cold injuries fall into two broad categories. Localized injuries include chillblains and frostbite. Systemic hypothermia is a metabolic inability to maintain body temperature. We lose heat via conduction, convection, evaporation and radiation. Radiation is responsible for 55 to 65 percent of our heat loss. Evaporation occurs through the skin and airway and accounts for about 30 percent. Panting dogs are good examples of the efficiency of this system. When dry, we only lose maybe 15 percent of our heat via conduction. However, the thermal conductivity of water is roughly 30 times that of air, so being wet when it is cold out can drive the human body into a state of hypothermia with alarming speed. Convection heat loss is typically trivial in the absence of significant wind.

Systemic Cold Injury

Systemic cold injury is characterized by a drop in core body temperature to 95 degrees Fahrenheit or below. Battling systemic hypothermia means addressing each of these heat-transfer mechanisms. Immersion in water or being buried in an avalanche are two of the more common mechanisms of catastrophic hypothermia. In both of these disastrous cases, speedy removal from the snow or water and subsequent rewarming is critical to survival.

Hypothermia manifests as rapid heart rate and breathing, increased muscle tone and shivering. Clinical symptoms include dizziness, joint stiffness, fatigue, nausea and itching. Eventually judgment is impaired, speech becomes slurred, motor coordination is lost, and confusion ensues.

Deep Freeze Dangers

Localized cold injuries are divided into frostnip, chillblain, immersion foot and frostbite. Frostnip is a non-freezing injury typically localized to spots like the end of your nose or fingertips. These injuries are readily addressed through local warming. Chillblain is a variation on this theme that is typically associated with damp conditions. Chillblain can result in a persistent vasculitic effect that can manifest as blisters or ulcers and can persist several weeks after warming.

Immersion, or trench foot, occurs when feet are wet and cold but not frozen for a protracted period. Symptoms include numbness, pain, itching and muscle cramps. In severe cases, superficial liquefaction gangrene can occur with subsequent limb amputation. Avoiding trench foot means keeping the feet dry, clean, and warm by air drying and changing socks regularly while wearing appropriate foot gear.

Frostbite Dangers

Frostbite occurs when tissues actually freeze. There are two classified degrees of severity—superficial and deep. Frostbite will manifest as skin that is waxy, cold and pale. The affected part is painless until warmed and thawed. Swelling and large clear blisters typically appear within 24 hours of warming. In severe deep frostbite, underlying tendons and muscular structures are affected and the extremity is hard and wood-like, even after warming. As you might imagine, severe deep frostbite seldom ends well. Severe frostbite is quite dangerous and should
be treated immediately by trained medical professionals.

Preparation, keeping warm and dry, wearing appropriate clothing and avoiding dangerous conditions are the cumulative ways to manage cold injuries. If you get wet when it is cold out, get out of your wet clothes as soon as possible and warm up quickly. If cold weather is a threat, keep a sleeping bag in your vehicle along with the means to make a fire. Layer your clothing according to the forecast and prepare for the worst case. Modern advances in fabrics and gear can keep you warm, safe and comfortable in the most wretched environments. As always, consider the seriousness of these environmental threats in advance and prepare accordingly. Your life just might depend on it.

This article was originally published in SURVIVOR’S EDGE. Subscription is available in print and digital editions here.

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