Outdoor workers – including lineworkers and communications technicians – routinely work in hazardous environments. Most of these hazards are well-recognized and understood by the workers and their management, but that is not always the case with cold-weather injuries, such as hypothermia and frostbite. Until workers receive specific and relevant training from medical professionals with cold-weather experience, they may lack the basic understanding of just how suddenly cold weather can kill.
Although there are numerous types of cold-weather injuries, this article will address the most common one: hypothermia, or the human body’s attempt to manage a drop in its core temperature. The core includes the brain, heart, lungs and neck. When managing body core temperatures, keep in mind that more blood flows closer to the skin in the neck than anywhere else in the human body.
Any drop in the temperature of the core blood will trigger a response from the hypothalamus in the brain, which is responsible for all body thermoregulation. The hypothalamus has three separate and unique methods that it will use, in sequence, to respond to a lowered core temperature, referred to as stage 1, stage 2 and stage 3. Failure to recognize the differences between the stages can immediately be fatal to a hypothermia victim.
The Three Stages
Stage 1 hypothermia occurs when the body’s core blood temperature first drops. The hypothalamus initiates two major responses to this temperature drop, only one of which the victim is aware. The first response is the hypothalamus triggering the major muscle groups – those in the arms, legs and face – to shiver. This is mild at first but then progresses to severe and uncontrollable shivering. The second response, which the victim is unaware of, is the brain triggering the release of larger quantities of sugars and insulin into the bloodstream. This is necessary to support the hard muscular work involved in shivering.