Sunday, June 19, 2022

Hypothermia, It Can Happen Any Time, Anywhere ©

 

 

Cold, wet, rain, hypothermia weather.  Taken in Snohomish County, Washington”, by pfly, from Wikimedia, HERE.


If you are like most people, you probably consider hypothermia as something to only worry about in the depths of winter, when it is freezing cold outside.  But you would be wrong!

 

Hypothermia means “low heat” and it can happen anytime you lose your core body heat faster than you can replace it.  It can strike anytime, anywhere, indoors, or out, even in relatively warm 50oF (10oC) temperatures!  And while hypothermia is common in the winter, according to Princeton University it actually occurs most often during the spring and fall1 and can occur also in the summer.  Unfortunately, prominent Seattle hiking expert Karen Sykes, who was 70 years old, died of hypothermia on June 18, 2014, while hiking the Owyhigh Lakes Trail in Mount Rainier National Park which has a maximum elevation of 5,272 feet (1,607 m)2.

 

Hypothermia is defined as a cooling of the body’s core temperature to below 95oF (35oC) and is often caused by a combination of three factors, cold or quickly changing temperatures, strong winds, or being wet, either from rain, sweat or being immersed in cold water.  Four other factors that contribute to hypothermia are high elevations, which can experience quickly changing wind and weather; age, because the very young and the old have a harder time regulating and maintaining their body heat; dehydration, which decreases your body’s ability to regulate its thermostat; and fatigue or exhaustion, because low energy means you have less to burn to keep you warm. 

 

How you lose heat...

 

“Illustration of the basic methods heat loss”, by Baedr-9439, February 25, 2020, modified by the Author with material from A Pocket Guide to Cold Water Survival, by the Coast Guard .  Original from Wikimedia, HERE.


Your body loses heat through four processes, convection, conduction, radiation, and evaporation.

 

Convection or wind chill can cool you very quickly.  Alan E. Course, in The Best About Backpacking, wrote “a two-mile-an-hour breeze can drag down body temperature as effectively as a twenty-mile gale if the victim’s clothes are wet”.  Your body will lose between 10% to 15% of its heat through convection.

 

You lose body heat by conduction to the ground, if you are sitting or sleeping on snow or the ground, to the air around you, or to water if you are swimming or immersed in it.  Body heat is lost to the air at temperatures lower than 68°F (20°C), and your body will lose about 2% of its heat by air conduction.  However, you lose body heat to water about 25 times faster than to the air, so you can lose body heat very quickly if you are in cold water or wearing wet clothing.

 

Radiation is the process of heat moving away from your body, like heat leaving a hot stove, and usually occurs in air temperatures lower than 68°F (20°C).  The body loses 65% of its heat through radiation.

 

You will lose body heat by evaporation of water from your skin if you are sweating, or from your clothing if it is wet.  During heavy exercise, your body will shed 85% of its heat by sweating.  Also, you lose some body heat through respiration (breathing).  Heat loss by evaporation and respiration will increase in dry or windy conditions.

 

What is Hypothermia...

 

From A Pocket Guide to Cold Water Survival, by the Coast Guard, page 7.


Hypothermia is the lowering of your body’s core temperature to 95oF (35oC) or below and has three stages, mild, moderate, and severe. 

 

Mild Hypothermia is when your core body temperature falls from 98.6o (37oC) to between 95o and 90oF (35o to 32oC).  The symptoms of mild hypothermia are intense, but controllable shivering and cold numb hands or the “fumbles”3. 

 

Moderate Hypothermia is when your core body temperature falls from 90o to 86oF (32o to 30oC).  The symptoms of moderate hypothermia are uncontrollable shivering, confusion and movements that become slow and labored, and slurred speech -- look for the “stumbles”, the “mumbles”, and the “grumbles”.

 

Severe Hypothermia is when your core body temperature drops to between 86o and 78oF (30o to 25oC).  The symptoms are extremely cold skin, sleepiness or unconsciousness and a pulse that is irregular or difficult to find.

 

Stay at 98.6o...

 

Stay at 98.6o, an excerpt from A Pocket Guide to Cold Water Survival, by the Coast Guard, page 2.


There are five things that you need to do to keep yourself at 98.6oF (37oC), and to avoid hypothermia: dress in layers, stay dry and keep “comfortably cold”, stay hydrated, eat often, and be prepared.

 

Stay warm.  Always dress in layers, because the layers will help trap your body heat close to your skin and will prevent the wind and the wet from stealing it away.  Wear an inner layer of synthetic weave to wick away the sweat, a middle layer of synthetic, down or wool to provide insulation and an outer waterproof/windproof layer to break the wind.  And always take a knit hat, a knit hat is essential because heat loss from your bare head can be 50% at 40oF (4oC) and 75% at 5oF (-15oC).  Bringing extra dry clothes in case you get wet or an extra insulative layer in case the temperature drops is also, always a good idea.

 

From A Pocket Guide to Cold Water Survival, by the Coast Guard, page 6.


Stay dry!  If it is wet out, put on your waterproof layers or take shelter.  And stay “comfortably cold” by taking off your insulative layers or your knit hat as you become too warm, because as Les Stroud, The Survivorman says, “You Sweat You Die”! 

 

From A Pocket Guide to Cold Water Survival, by the Coast Guard, page 12.


Stay hydrated and stay fed.  Even low levels of dehydration of less than a 2% loss of body weight4, can lower your blood volume and affect your circulation and your body’s ability to regulate its thermostat, this can result in hypothermia.  Also, your body uses food as energy and it takes energy to make heat, so, when it is cold, you must eat more often.  But remember you need to have water to digest your food, so if you don’t have water, don’t eat.

 

Be prepared.  Always dress for the worst weather you might experience, your first line of defense against the cold and the wet, are the clothes you are wearing and the extra clothes that you have with you.  Especially during the spring, summer and fall, travelers in the wilderness often do not bring enough, or bring the right kinds of clothes.  And always, bring a tent, a tarp, or some way of making an emergency shelter with you, when you go out in the wilderness.  If a storm blows up make camp right away, because setting up camp takes time and energy, and if you are cold, you might not have much of either.  Personally, I always carry two heavy grade, 55-60 Gallon, 3.0 Mil, 38"W x 58"H, contractor trash bags, in case I have to make an emergency trash bag shelter (for more see “Using your poncho or a trash bag as an Emergency Shelter ©”, HERE, or for a video, go HERE).  

 

So, be safe, keep warm and dry and stay at 98.6oF, spring, summer, fall, or winter!

 

Don’t forget to come back next week and read “Mayapples...They Aren’t Really Apples ©”, where we will talk about a common woodland flowering plant that really isn’t a what it is called, and which appears during the spring and disappears by mid-summer.

 

 

I hope that you continue to enjoy The Woodsman’s Journal Online and look for me on YouTube at BandanaMan Productions for other related videos, HERE.  Don’t forget to follow me on both The Woodsman’s Journal Online, HERE, and subscribe to BandanaMan Productions on YouTube.  If you have questions, as always, feel free to leave a comment on either site.  I announce new articles on Facebook at Eric Reynolds, on Instagram at bandanamanaproductions, and on VK at Eric Reynolds, so watch for me.

 

That is all for now, and as always, until next time, Happy Trails!

 

 

Notes

 

1 “Cold Stress Facts”, Environmental Health and Safety, Princeton University

 

2 From Eric M. Johnson, “Seattle hiking expert Sykes died of hypothermia: official” and Pro Trails, “Owyhigh Lakes - 7.0 miles”.

 

3 Watch out for the “umbles”: the fumbles, a sign of cold numb hands and mild hypothermia, and the mumbles, stumbles, and grumbles, a sign of confusion and slowed thinking and movement, all of which are symptoms of moderate hypothermia.

 

The best field test for early or mild hypothermia, is to ask the person to walk in a straight line, if they are unable to walk 20 to 30 feet (6 to 9 m) in a straight line, they might be hypothermic.

 

From “Warning Signs of Hypothermia: Know Your ‘Umbles’”, by Matt Heid.

 

 

4 From “Dehydration, Hyperthermia, and Athletes: Science and Practice”, by Robert Murray, PhD.

 

 

Sources

 

Coast Guard, Department of Transportation, A Pocket Guide to Cold Water Survival, CG 473, September 1975, https://books.googleusercontent.com/books/content?req=AKW5QafxNJBmiIml6O4jiudRpr2rz8pLfodQOiq-4gZNh4xa5uIN_rq05C2yAes1AYw67Ziq189QaQaFDHBHE0SJivfCxjMW1DReANLjFqw1qX6jEl2mz1HPKXj4BRQJv8zAOcO6oDE70Dcv__VE2uPh4tEqLSzMxDRiWOv3p6ssyQjE2bevJMX7-Ol2KDtIPQVcVuaJudJMLaOOuSUVs8qYS1Nlaxnm47GVOCXLR79KzL6nV3R0zZG4DxRt9hoYrIRGugXm6RVfbU2gxeix7JLKbxpvQsNB9w, accessed May 1, 2022

 

Environmental Health and Safety, “Cold Stress Facts”, [© 2022 The Trustees of Princeton University], https://ehs.princeton.edu/workplace-construction/occupational-health/heat-cold-stress/cold-stress-facts, accessed June 14, 2022

 

Heid, Matt; “Warning Signs of Hypothermia: Know Your ‘Umbles’”, February 11, 2014, [© 2022 Appalachian Mtn Club], https://www.outdoors.org/resources/amc-outdoors/health-and-safety/warning-signs-of-hypothermia-know-your/, accessed June 18, 2022

 

Johnson, Eric M.; “Seattle hiking expert Sykes died of hypothermia: official”, June 24, 2014, [© 2022 Reuters], https://www.reuters.com/article/us-usa-hiker-washington/seattle-hiking-expert-sykes-died-of-hypothermia-official-idUSKBN0EZ0OQ20140624, accessed June 14, 2022

 

Murray, Robert, PhD.; “Dehydration, Hyperthermia, and Athletes: Science and Practice”, Journal of Athletic Training, July-September 1996, 31(3), pages 248–252, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1318513/, accessed June 18, 2022

 

MyHealth.Alberta.ca, “Cold Exposure: Ways the Body Loses Heat”, [© 2022 Government of Alberta], https://myhealth.alberta.ca/Health/pages/conditions.aspx?hwid=tw9037#:~:text=Convection%20(similar%20to%20sitting%20in,of%20its%20heat%20through%20convection., accessed June 18, 2022

 

Pro Trails, “Owyhigh Lakes - 7.0 miles”,[ © 2021 ProTrails], https://www.protrails.com/trail/851/mount-rainier-national-park-owyhigh-lakes, accessed June 18, 2022

 

Van Lear, Denise; The Best About Backpacking, [Sierra Club, San Francisco, 1974], page 355

 

Wikimedia; Cold, wet, rain.  Taken in Snohomish County, Washington”, by pfly, November 12, 2007, https://commons.wikimedia.org/wiki/File:Rain_shower_after_cold_front_3.JPG, accessed June 10, 2022

 

Wikimedia; “Illustration of the basic methods heat loss”, by Baedr-9439, February 25, 2020, https://commons.wikimedia.org/wiki/File:Mechanisms-of-heat-loss.png, accessed June 17, 2022

 

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