Your
body is a machine, and food IS fuel, or as they say in the prepper
commercials “calories are life”. Humans
are warm blooded and must continuously metabolize food to produce heat to stay
at 98.6o F (37o C) and sustain life, and this heat is
measured in calories.
This
heat production is either basal metabolism from unconscious and continuous body
processes, or muscular metabolism, which is consciously controllable. The harder you work the more energy you burn
and the warmer you get.
Each pound
of fat, equals two days of fuel...
In
a survival situation food is usually your last concern, especially when you
consider that 82% Americans are carrying too much body weight on their body’s. Up to 30% of Americans are overweight, having
up to 34 pounds (15 kgs), of extra fat, while 42% of Americans are obese, carrying
between 35 and 103 pounds (15 - 47 kg) of fat on their bodies, and 9% of
Americans are severely obese, carrying more than 103 pounds of spare fat on
their bodies2.
Research
has shown that about 3,500 calories of energy is equal to about 1 pound (0.45 kg)
of fat. Most women need between 1,600 to
2,000 calories per day to maintain their weight, while most men require 2,000
to 2,400 calories per day. For example,
a sedentary 130-pound woman needs about 1,700 calories, while a 175-pound,
inactive man requires about 2,300 calories daily to maintain a healthy body
weight. Your caloric requirement may be
more or less.3
So,
each pound of fat, on average, is equal to two days of fuel energy for the
average woman and about 1-½ days for the average man. And this means that for more than 18% of
Americans, you could live for longer than 22 days on just your stored body fat!
During
long periods of fasting, you will still experience nutritional deficiencies because
of vitamin and mineral depletion, but you won’t starve.
Heat loss....
Since
human comfort depends on maintaining a skin temperature of 91o F (33o
C), clothing insulation is required at temperatures below 68o F (20o
C). Because even at an ambient
temperature of 68o F, a naked human must maintain a metabolic rate
of 125 Cal./m2/hr., which is the
equivalent of light work or a slow, level walk at 2-½ miles per hour, just to
stay in thermal equilibrium!
The
colder it is the more energy is required to maintain a 98.6o F, 37o
C, normal core body temperature. You can
either put on more clothes or you can burn more energy to keep warm. For more information on the insulation value
of clothes read “Clo Values...What’s That?©”, HERE.
Humans
constantly lose metabolic heat generated by living and life activities to the
surrounding environment, through an exchange based upon conduction, convection,
radiation, evaporation, and heat production. Of the 50 Cal./m2/hr. of metabolic
body heat produced while sitting inside in a chair,
most of the the body’s heat, 76% (or 38 Cal./m2/hr.) is lost as
radiation, conduction, and convection from the skin through the clothing, and
the remaining 24% (or 12 Cal./m2/hr.) is lost to evaporative cooling
from the skin and lungs.
This
heat loss must be made up by burning more fuel to generate heat. The greater the heat lost to the environment
from wind, wet and weather, the faster your store of calories are expended.
Additionally,
humans burn and maintain heat differently based on sex, with men tending to
produce more heat than women, and body mass.
Heat production is proportionate to body mass, but heat dissipation
depends on body surface. A thin or small
person has a greater surface to volume ratio than a larger or more rounded person
and will lose heat faster to the environment.
Also, being injured makes it more difficult to maintain your thermal
balance, and an injured person is at greater risk of exhaustion and hypothermia
than an uninjured person.
Exhaustion
and hypothermia...
Exhaustion
is when your body runs out of energy reserves and heat production falls below
what is required to maintain your normal core body temperature of around 98.6o
F (37o C). Hypothermia is when
your body loses heat faster than it can produce heat, causing a dangerously low
body temperature, and occurs when your body temperature falls below 95o
F (35o C).
Don’t forget to come back next week and read “The North Pole Is/Was
Here ©”, where we will talk about the wandering magnetic North Pole.
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 “...the
normal body temperature's 98.6. Once it
starts to drop down around 97 or 96, you're going to start shivering. And that's just your body's way of trying to
produce heat. You shiver. It produces heat. It tries to warm up the core. But the really concerning thing is if you
stop shivering. That's when your body
temperature gets less than 90 degrees, and that's where it becomes life
threatening”.
From
Dr. Troy Madsen, from “Do I Have Hypothermia, or am I Just Really Cold?”, January
19, 2015
2 From
National Institutes of Health; “Overweight & Obesity Statistics”
3 From
Erin Coleman, R.D., LD, “Calorie Requirements for Men & Women”, July 5,
2013, and “Don't count calories, but be aware of them”, October 20, 2023, by Harvard.
Sources
Coleman,
Erin, R.D., LD; “Calorie Requirements for Men & Women”, July 5, 2013, [©
2023 Hearst Newspapers, a division of Hearst Communications, Inc.], https://www.weekand.com/healthy-living/article/calorie-requirements-men-women-18004997.php,
accessed December 9, 2023
Eisberg, Harry Belleville; Owens, J. E.; Fundamentals of Arctic and Cold Weather
Medicine and Dentistry, [U.S. Navy Department, Washington, DC, 1949], https://books.google.com/books?id=2-bYnbMCwYQC&pg=PA80&dq=clo+values&hl=en&newbks=1&newbks_redir=0&sa=X&ved=2ahUKEwjJtpavyMuCAxU0KlkFHWKIByYQ6AF6BAgFEAI#v=onepage&q=clo%20values&f=false
Harvard; “Don't count
calories, but be aware of them”, October 20, 2023, [©2023 Harvard Health
Publishing® of The President and Fellows of Harvard College], https://www.health.harvard.edu/healthbeat/dont-count-calories-but-be-aware-of-them#:~:text=Most%20women%20need%201%2C600%20to,may%20be%20more%20or%20less.&text=Another%20approach%20is%20to%20simply,the%20effect%20of%20limiting%20calories,
accessed December 9, 2023
Havenith, George; “Clothing
and Thermoregulation”, Current Problems in Dermatology, February 2003 Volume 31,
pages35-49, https://www.researchgate.net/publication/10643719_Clothing_and_Thermoregulation/download?_tp=eyJjb250ZXh0Ijp7ImZpcnN0UGFnZSI6Il9kaXJlY3QiLCJwYWdlIjoiX2RpcmVjdCJ9fQ,
accessed December 9, 2023
Lounsbury, Dave E. MD,
FACP, Colonel, MC, U.S. Army, Editor in Chief and Director; Medical Aspects of
Harsh Environments, Volume 1, [Office of The Surgeon General at
TMM Publications, 2001] page 496-497, https://books.google.com/books?id=0xGGOJpUbK0C&pg=PA496&dq=exhaustion+hypothermia&hl=en&newbks=1&newbks_redir=0&sa=X&ved=2ahUKEwi3r63ooIODAxV3rokEHdiZCeQQ6AF6BAgGEAI#v=onepage&q=exhaustion%20hypothermia&f=false,
accessed December 9, 2023
Madsen, Dr. Troy; “Do I Have
Hypothermia, or am I Just Really Cold?”, January 19, 2015, [© 2023 University
of Utah Health], https://healthcare.utah.edu/the-scope/health-library/all/2015/01/do-i-have-hypothermia-or-am-i-just-really-cold#:~:text=So%20you%20think%20the%20normal,You%20shiver,
accessed December 9, 2023
National
Institutes of Health; “Overweight & Obesity Statistics” [U.S.
Department of Health and Human Services], https://www.niddk.nih.gov/health-information/health-statistics/overweight-obesity#:~:text=Adults,-Age%2Dadjusted%20percentage&text=the%20above%20table-,Nearly%201%20in%203%20adults%20(30.7%25)%20are%20overweight.,obesity%20(including%20severe%20obesity),
accessed December 9, 2023
Rathbone, Thomas M., Lt.;
“Bligh’ Me-Survival at Sea”, Surface Warfare, Volume 5, Issue 11, November
1980, page 16 to 17, https://books.google.com/books?id=XNQDYsVnxQIC&pg=PA17&dq=body+fat+survival+sea&hl=en&newbks=1&newbks_redir=0&sa=X&ved=2ahUKEwiwgovgmb6AAxVMGFkFHZwTDak4ChDoAXoECAYQAg#v=onepage&q=body%20fat%20survival%20sea&f=false,
accessed August 7, 2023
No comments:
Post a Comment