What is “Core Temperature” – How important is it – What you need to do and know!

Hello Hikers,

A few years ago as I was developing my long distance hiking skills I realized a very important aspect of hiking which I eventually formulated into a sort of motto by which I hike – and now use as a principle teaching platform.

Managed Core Temperature + Proper Preparation + Proper Sleep + Proper Food + Proper Gear = A High Chance of a Successful Trip!

I am fully convinced that nearly everything you learn about hiking should be founded on those 5 skills!

It does not take a great deal of time spent out hiking to realize just how important those four skills are. The difficulty comes in learning them and learning how to keep yourself aware of each of them, and learning how to keep yourself in tune with each of them regardless of the environment  and conditions that you are faced with while out on the trail.

It would be unfair of me to sit here and say that I have mastered each of those four aspects, because I have not. There are times I am on a hiking trip and I realized that I have highly under estimated the situation and end up not being able to properly sleep – usually it comes down to the cold or hot weather, or from not having enough water or food to keep my body in tune with itself.

Most hikers know the old yet so true statement “sweat kills”. I think for those who are not skilled in the aspects of maintaining a core temperature this can be very true. However, I think that once you learn about how to properly maintain your core temperature you can survive most situations where you find yourself sweating and in a bad situation.

Here are some of the most important aspects to learn:

Core temperature is not the same as peripheral temperature!

A persons ‘core temperature’ has to do with structures deep within the body, where as ‘peripheral temperature’ has to do with skin level temperatures. Remember that, it can save your life! In the most basic of layman’s terms: what your skin temperature feels like might not be what the temperature is of your core organs! And remember that it can go both ways! In some situations your skin might feel really hot yet your core organs can be freezing and starting to shut down.

Where Is Your Core Body?

Your core is not your chest area – your core is your head to mid-chest! Hikers have three main organs to care about: your heart, your lungs and your brains.

Many people think that their “core temperature” is all about “their chest cavity” but that is just so wrong.

How often have you heard the statement “If your feet are cold, put on a warmer hat“. This is a prime example of these illustrations.

You might often wonder why hikers walk around with a down vest on yet do not have a down hat or balaclava on as well. Personally, so do I. It completely befuddles me why hikers do this. I cannot tell you how often I get strange looks for wearing my Black Rock Gear hat when I am out hiking in temperatures even a few degrees below what I am typically use to. It makes no sense at all to me why people wear vests thinking they are doing a darn bit of good yet not wear a hat. The brain might be a very small fraction of your body’s overall mass (at ~3 lb the brain is only ~2% of a typical body’s overall weight) but it uses an enormous amount (~20 – 25%) of the body’s energy. In addition 15% of your heart’s cardiac effort, and 20% of our oxygen supply is used to operate your brain.

It is vital that you keep your brain, your heart and your lungs as stable as possible in regards to your core body temperature.

When Things Go Wrong:

Onto the next important issues, that of heat exhaustion and heat stroke. Honestly there is very little need for me to sit here and write either complicated or simplified explanations of what each of those are. Any hiker going out on a trip without the most basic understandings of thermoregulation needs to seriously consider the wisdom of the decisions to go out.

I am not talking about every hiker needing to be a doctor or a nurse or a emt or such, but rather the most basics of understanding the differences between a heat stroke and a exhaustion – and knowing when you are about to suffer from them, and when you are suffering from them, and how to treat each of them!

Perhaps the greatest thing to learn is to know when your body is telling you something is wrong. I do not mean for that to sound like one of those “duh” statements, but there are signs to know when things are about to go wrong, learn what they are and how to prevent them!

Layering Systems:

Onto the next aspect of your core-temperature, thermoregulation. For most folks, you probably understand thermoregulation as “multi-layering” of your cloths.

The human body by itself is rather efficient at behavioral thermoregulation. At times though, behavioral thermoregulation (that is, the ability of the body to regulate its own core temperature) has its limitations and we meer human beings must use our own brain to regulate our core temperature.

What I would like to present is my personal five part multi-layering systems. I realize multi-layering systems are about as complex as eukaryotes so I will not get into the whole debate of “how many layers should a layering system have” because I think many hikers eventually develop their own layering system that is unique to them, and that is exactly how I think the approach should be. But I would like to briefly share why I have gone with a five layer system.

Remember that each “layer” has both a top and a bottom. So at the most I carry ten distinct clothing items which make up the overall layering system.

The layering system I will present below is for colder weather situations that I typically face, which are at the coldest around 15-20 degree Fahrenheit. Much below that and I would personally just rather stay home, I realize that makes me a wimp for you folks in Minnesota and other parts of the world. The average temperature where I live in the winter season is (low) 40.8°F and (high) 55.0°F. The annual precipitation averages 38.1 inches (968 mm) with measurable precipitation on an average of 119 days each year. The all-time highest and lowest temperatures recorded in my area are a high of 87 °F (31 °C) on October 26, 1993, and 20 °F (−7 °C) on January 14, 1888. So as you can see, I live in a very stable weather region of the USA – one of the reasons I love the Redwoods!

The first layer for me, next-to-skin, is nearly always a long sleeve shirt (for the top layer) and briefs (for the bottom layer). I am constantly amazed to see how many hikers have made the switch over to using light weight long sleeve shirts. Not only do they provide that initial layer against your arms to keep the warmth in but they provide exceptional protection against the sun. For the past few years my preferred top base layer has been the “Patagonia Capilene 1 Crew silk” though I am looking really hard at making the switch over to a Icebreaker base layer top. For my bottom base layer, I prefer the ‘ExOfficio Men’s Give-N-Go Boxer Briefs’.

For my second layer, on the bottom I typically have on pair of the “Montbell Dynamo Wind Pants” which are 12-denier rip-stop Ballistic Airlight nylon. When it gets cold I will put on a pair of “Patagonia Capilene 3 Bottoms“. For the top I will put over my Cap1 Silks a pair of “Patagonia Capilene 3 Tops“.

For my third layer, on the bottom I do not have anything else. I have not yet found a time when the Patagonia Cap3 bottoms and my MB Wind Pants have not kept me warm while sleeping or around camp. My legs tend to stay much warmer than my upper body. For my upper body, over the Patagonia Capilene 3 Tops I will put on my “Montbell Tachyon Wind Jacket” an amazing 2.3 ounce jacket made from 7-denier rip-stop Ballistic Airlight nylon which holds a much greater amount of heat in than I would have expected.

For my fourth upper layer I will put on my “Montbell U.L. Down Inner Parka“. This puffy jacket allows me to get down into the colder levels, around 20 by itself and the other layers listed above. Depending on whether it is raining or misting I either wear it on the outside or the inside of the Tachyon.

For when it becomes very cold (below 20) I will add on my “fifth layer”, which is actually a cuben fiber rain jacket from ZPacks.Com called the “Cloud Jacket“. I realize to some that it might seem strange (and I would probably agree with them, except it ‘works’ for me) that I would use a rain jacket as my “hardshell outter layer” but when you consider that the jacket is made from cuben fiber, and you understand that cuben fiber is non-breathable, you can understand that the jacket not only provides rain protection, but because it is non-breathable it means that very little hot air from my body is allowed to escape. It becomes a near perfect XUL layer that serves double-duty.

So that is the general overview of how I maintain my core body temperature. Through the adding and removing of those fiver layers of clothing I find I have the ability to do rather well making sure I keep my body warm in the cold season.

What about my feet, head and hands?

Socks/Feet. I will admit that I have a pretty deep love for the “Darn Tough Merino Wool 1/4 vented Socks“. When it gets to cold for them, I will put on a second pair of them. If my feet still get cold I have a pair of “Sealskinz Waterproof Mid-Calf socks” socks that I put on. I again realize this might not make any sense, so allow me to explain. Yes, SealSkin socks are waterproof, but what does that mean? It means that the material is designed to allow water to stay out – but it also means that the material keeps warm air in! I have not yet encountered a time when the two pair of Darn Tough socks plus the SealSkins socks were not able to keep my feet warm, thankfully.

Head. As I mentioned above, I really love the Black Rock Gear hat. It has proven to me to be a wonderful base-layer for my head. When it gets to cold for that hat I will put on the “ColdAvenger Expedition Balaclava” – which I fully realize looks really weird, but works amazingly well. It uses a breathable fleece and I cannot ever remember a time having my head cold while wearing it. As for the ventilator, it might seem strange, but I can speak as somebody who has actually used it and can say, it really does work! This ‘ventilator’ becomes one of the primary means of thermoregulation for your lungs (remember we talked about your lungs being one of the important three!) along with a good puffy jacket or vest.

Hands. For my initial base layer for my hands I wear the “Possum Plain Gloves” from a company in New Zealand, which are a combination of 40% Possum fur, 50% New Zealand Merino wool, and 10% Nylon. They are the most amazing gloves I have ever owned. Wet or dry, my hands are warm! I also wear a pair of glovelets from PossumDown which have now been discontinued. They are similar to the new version but are ribbed and fingerless. They extend around 6 inches or so up my arm. I love them too! My next layer for my hands are the “Outdoor Research Flurry Gloves“. When it gets to cold for them, I recommend the “Black Rock Down Inner Down Mitts(read my review on them). For a hard shell layer I highly recommend the “eVENT Rain Mitts” by Mountain Laurel Designs. I also look forward to trying out the “Ultralight Rain Mitts” from Black Rock Gear once they are released.

In Closing:

So that pretty much finishes off what I had to share today about what I feel are some of the most important aspects of core-temperature.

“Core temperature” is not only a matter of what the temperature outside is – it is also a matter of knowing what are the most important parts of your body to keep regulated (remember the three: your brain, your heart and your lungs) and how to detect the signs of core temperature extremes, how to treat core temperature extremes, and most importantly of all, having a firm and properly understanding of how to layer your clothing in order to help your body maintain its own behavioral thermoregulation.

This article was originally published at http://www.redwoodoutdoors.com/

(Standard Disclaimer: This is not paid advertisement. I do not get paid to write. I do not get paid to review gear. I do not get paid to do prototype testing – and no matter what I refuse to do industry testing and evaluation if it including being forced to write a review about it. I simply will not write reviews on gear I have not bought. I keep it real. Furthermore, I am not a doctor and nothing in article should be considered official and legal advice on how to handle YOUR OWN body.)

15 thoughts on “What is “Core Temperature” – How important is it – What you need to do and know!

  1. Great article. I find that selecting upper body layers with 1/4 chest zippers that allow me to cover or expose my chest and neck really helps avoid having to stop to remove or add a layer. Also rolling up my sleeves to expose my wrists is an easy way to shed some heat. Add thin wool glove liners and a thin wool toque and you have a wide range of venting/insulating options. This knowledge is especially important when winter backpacking when the number one rule is to avoid sweating into your insulating layers.

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