Hypothermia and Hyperthermia
They sound the same, don’t they? But don’t be confused. In the following two articles we will clearly explain the differences and do our best to inform you how to avoid it and what to do should it happen.
This article will be about Hypothermia but before we begin, lets provide an initial explanation to avoid confusion.
Hypothermia – Refers to the cooling of the human body which in severe cases can result in death.
Hyperthermia – Refers to the elevated temperature of the human body due to a failure of thermoregulation and in severe cases can result in death.
The bodies core temperature is normally around 37 deg C. When the core temperature drops, Hypothermia starts to set in. A drop of below 35 deg C signifies mild conditions whereas anything below 33 deg C is considered severe.
“Hypothermia occurs when an individual’s core body temperature decreases to a level where muscular and cerebral functions become impaired. The most common cause of this loss of body temperature is exposure to cold and/or wet conditions. When exposed to cold conditions, the body can lose heat through a variety of routes. These include conduction (contact with cold or wet objects, such as snow or wet clothing), convection (heat being carried away from the body by wind, i.e., wind chill) and evaporation (sweating and respiration). Once the body’s core temperature begins to drop, the symptoms of hypothermia will begin to appear.”Grainger.com
Let’s be clear here, conditions on the trail, fell or mountain don’t necessarily need to be bad for Hypothermia to set in. Running and moving fast creates heat and a runner can generate a great deal of heat in a short space of time. Imagine a scenario where you are moving fast, and you have been travelling this way for say 2-hours. You are warm, no hot! You are a little fatigued, hungry, a little dehydrated and then disaster happens…. you fall and twist an ankle.
Suddenly moving becomes impossible and you start to cool.
I probably don’t need to elaborate too much here as it’s very easy to see and visualize the scenario that follows.
Low blood sugar, low energy a cooling body and mild Hypothermia starts to set in. Conditions do not need to be bad or inclement for this to happen! However, bad weather only adds to the situation and can speed up any decline. Imagine the scenario where conditions are bad – rain, wind, snow, ice, windchill and so on. The Hypothermia process is then escalated and speeded up rapidly requiring much faster action from the individual who is impacted by the conditions and those around who can provide help.
As the body cools, certain things start to happen and in mountain running we always warn runners of the possible signs of Hypothermia – Mumbles Grumbles and Stumbles.
Look out for:
An inability to make decisions.
A reduction of consciousness.
In severe cases any shivering may well stop and you will see visual signs of change such as blue lips.
- Speed is of the essence with Hypothermia as mild conditions can spread quickly and before you know it, they can become severe and critical quite quickly.
- If you have additional clothing (you should have, see a post on mandatory equipment) put as many layers on as possible including hat, gloves, warm base layer and windproof. If you or the person are wet from rain, ideally you would remove wet layers and replace with dry.
- Ideally eat sweet foods. Avoid coffee, tea, and alcohol, If the victim can swallow without danger, give him/her warm, sweet liquids to drink.
- Place warm objects and add heat/ layers next to the victim’s head, neck, chest, and groin.
- If possible, get off the mountain or out of the bad conditions as soon as possible. If this is not possible, try to find shelter. If you are unable to move add as many layers as possible and seek assistance from the emergency services. A personal tracker such as Garmin InReach is a great addition to a mobile phone when out in remote and isolated environments.
- Keep a potential Hypothermia case awake if you are looking after someone. If you are suffering from Hypothermia, do everything possible to avoid losing consciousness.
Of course, the above is not a comprehensive and fool-proof guide as mountain conditions and the condition of the casualty should indicate what action to take.
Do not try to evacuate a severe on unconscious casualty. Seek the services of the professionals with an emergency call.
All the above can be avoided with good mountain practice and skills.
The recent trend and desire to move fast and light is all well and good providing that you can move fast. However, when you can’t move fast, that is when problems arise. Personal responsibility, self-awareness and an understanding of the challenge, terrain, and weather, at minimum, requires you take stock of the situation before departing on any adventure and always think of the worst-case scenario.
Ask, ‘Do I have enough items with me should I become immobilized in bad weather and need to wait for rescue or help?’ If the answer is no, you need to reassess your equipment.
Mandatory kit should be something that you take with you on all your adventures, particularly on mountain journeys when in remote and isolated places, be that in training or racing. The more extreme the terrain, conditions or risk of adversity, the more equipment you should take.
Also remember that altitude and going high can impact in multiple ways. For example, it may be warm and sunny in the valley, but the higher you go, weather systems can change completely. For every 100m of elevation gain, temperature can drop by 0.65 (+/-) degrees. 1000m of elevation gain could see 10 degrees cooler temperatures, add wind and other inclement conditions and suddenly, without the right equipment, you are in a difficult situation. Be prepared!
As a minimum carry with you: Read winter kit list.
- A pack that can carry at least 1ltr of liquid with capacity for mandatory kit
- Waterproof jacket and trousers to protect from the elements
- A base layer Top and bottom) ideally merino wool.
- A down or primaloft jacket that will retain heat/ warmth in wet conditions.
- Space Blanket
- Compass (know how to use it)
- Map (know how to read it)
- Mobile phone
- Spare food – energy bars or similar.
for more extreme conditions, consider the following:
- Bivvy bag
- Sleeping bag
- Spot tracker or similar
- Stove such as a Jetboil
- Dehydrated meal
The above to some of you may sound extreme, believe me, when you need the above, you will really need them, and you will be more than thankful that you have them with you. Also understand clothing, how it works, how to layer, what garments are best in what conditions. Educate yourself on the pros and cons.
Ideally always go to the mountains or remote challenging locations with company – buddy up!
Check the weather and make a sensible decision based on you, your ability, your objectives, and skill level.
Know the route that you are taking and tell a friend or family member where you are going, when you are going and when you anticipate returning.
Have a contingency plan with options to shorten or abort a route with quick and easy escape routes.
Have a mobile phone that is charged and contains relevant contact numbers for emergency services.
Can you read a map, take a bearing or do you have a phone or GPS device that will give you a location? This will be essential when requiring help. If you can provide a grid reference you will be rescued far quicker when a rescue party that needs to search for you. what3words is a phone app for this and is better then nothing in an emergency. OS Locate possibly a better option as it provides grid reference.
Look after each other and look after others on the mountain.
Know whistle signals – six blasts every minute signifies an emergency.
Hypothermia can happen to anyone, even the most experienced runners or mountaineers. However, if you are sensible, have the necessary equipment and understand your ability and the ability of those around you, the risk of Hypothermia should be reduced greatly.
In the next article we will look at Hyperthermia.
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