adapting to an outdoor environment remote areas emergency medicine and survival
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Adapting To An Outdoor Environment
Remote Areas Emergency Medicine and Survival
Objectives
Identify survival requirements of the human body.
Explain how the outdoor environment effects the major systems of the body.
Identify methods of adapting to functioning in the outdoor environment.
Objectives
Explain the importance of nutrition and physical conditioning in adapting to the outdoor environment.
Skill Performance Demonstrate layering principles using
typical ski clothing.
Vocabulary Acclimatization- the process by which the
body adjusts to a new environment.
Alveoli- the smallest air sacs of the lungs.
Homotherm- a human or other warm blooded animal that maintains a constant body temperature despite changes in environmental temperature.
Hyperventilation- deep rapid breathing
Vocabulary
Vapor barrier garment- a waterproof garment worn either next to the skin or over a thin garment of polypropylene.
Windchill effect- the cooling effect of the wind added to low environmental temperature.
Survival Requirements of the Human Body
Survival RequirementsFor basic survival the human body
needs:
Oxygen Stable body temperature Water Food Will to live Physical integrity
Oxygen
A necessary component of life
Is supplied to the body through the lungs and alveoli
A constant supply of oxygen is needed by the body
Oxygen
The body can be deprived of oxygen by injury or moving to high altitude
At high altitude the body can adjust through acclimatization.
Acclimatization
Acclimatization occurs... Hyperventilation
Improvement in the blood’s oxygen intake and oxygen-carrying capacity
Heart and skeletal muscle action become more efficient
Acclimatization
To encourage acclimatization allow enough time for a slow ascent to altitude.
Provide a rest day after ascent to 10,000 feet above sea level.
Oxygen
The body also can be deprived of oxygen by injury.
TemperatureThe mechanisms of the body work best
when it is…
Well fed
Hydrated
Properly rested
In good condition
Temperature
If these mechanism fail to maintain body heat in an optimal range, injury can occur due to cold such as frostbite or due to heat such as heat stroke.
Environmental Effects on Major
Body Systems
Heat Loss
The human body is composed of …
Core (nervous system, heart, lungs, internal organs)
Shell (muscles, skin and extremities)
Heat Loss
When the body attempts to adjust body temperature it may do so for the core at the expense of the shell temperature.
We must understand how temperature is lost and how to prevent the loss.
Heat Loss
Heat is lost or gained from the human body in five ways:
Conduction Convection Evaporation Radiation Respiration
Conduction
The direct loss of heat by contact The amount transferred depends on the
temperature difference and material involved
Convection
The transfer of heat when air of a different temperature moves across the body surface
Evaporation
Occurs when water or other liquids on the body’s surface are converted to vapor
Can be a beneficial loss in hot climates
Radiation
Is the transfer of heat to or form the body through infrared waves
Heat loss from uncovered skin is through radiation
Respiration
The heat lost as cool air is inhaled and warmed by the body before being exhaled
Heat also can be gained in this way during hot weather
Heat Loss
A body at rest at 21° C and average humidity loses
70% through radiation, conduction and convection.
27 % through evaporation
3% through body functions
Heat Loss
The body has voluntary and involuntary methods of both increasing and decreasing heat loss.
Methods of Decreasing Body Heat Loss
Involuntary Decrease
perspiration Shunt blood away
from the shell Decrease body
surface area (curl into ball)
Voluntary Add clothing
Seek shelter from chilling mechanism
Stay dry; get out of wet clothing
Heat Loss
The body has three methods for avoiding dangerous degrees of cooling:
Increase internal heat production
Add heat from environment
Decrease heat loss
The most energy efficient is to avoid the heat loss.
Methods of IncreasingBody Heat Loss
Involuntary
Increase perspiration
Shunt blood to the shell
Voluntary
Subtract clothing Seek shelter from
warming mechanism
Expose more skin Cool with water
Practical Ways of Decreasing
Body Heat Loss Avoid alcohol and nicotine
Avoid getting wet
Use personal floatation device
Avoid contact with cold surfaces
Protect from windchill effect
Avoid excessive respiratory heat loss
Practical Ways of DecreasingBody Heat Loss
Use optimal insulation materials for clothing such as: wool, polypropylene, down, polyester pile, etc.
Avoid cotton in cold wet weather
Use layering so that clothing can be added or subtracted as needed
Adequately cover body parts such as head, ears, finger, feet
Adapting to the Weather
Adapting
There are many things that we can do to help the body adapt to the outdoor environment.
Cold Weather Clothing Proper layering and the use of insulated
clothing can protect the body from cold
Use a four layer system of clothing
Select based on the environment and expected weather
Choose materials with insulating values
Layer one
Underwear-wool, thermax, polypropylene and blends; avoid cotton
Socks-wool or polypropylene, use one thin pair near skin with thick outer sock
Layer Two
Shirt-wool or polypropylene
Pants-same material as shirt; avoid cotton
Boots-activity dependent
Third Layer
Parka-down or fiberfill, wind and water proof
Wind pants-water and wind proof
Hat-wool or poly Mitten or Gloves-
glove liners
Fourth Layer
Extra layer such as quilted vest in pack
Other considerations Rain gear Vapor barrier
Cold Weather Survival Kit
Shelter Building Plastic tarp Shovel Nylon cord Folding saw, ax
Fire Building Waterproof
matches Firestarter Candle Knife
Signaling Whistle Mirror Flashlight change for phone Signal cards
Optional Therm-A-Rest Stove and fuel Sleeping bag
Cold Weather Survival Kit
Other Compass Map Metal pot and cup Emergency care
kit Toilet paper Sunglasses Sunblock cream
Lip salve Spare socks Spare mittens Canteen (full) Food Extra layer of
clothing Avalanche poles
Adapting to Hot Weather
Heat stress is related to both temperature and humidity.
Serious heat stress can occur if the core temperature rises above 40° C for a significant period of time.
Adapting to Hot Weather
The body adapts in the following ways: Blood volume increases Heart efficiency improves Perspiration starts sooner and
increases in volume Perspiration contains less salt
Adapting to Hot Weather
Increasing Body Heat Loss Expose as much
skin as possible Wear light loose
cotton clothing Drink plenty of
fluids Acclimatize
Reducing Heat Gain from the Environment Wear protective
clothing Seek shade Avoid hot objects Do not lie on
ground Decrease muscular
activity
Nutrition and Conditioning
Lack of proper nutrition can cause weight loss, depression, apathy, and lack of coordination
Poor nutrition and fitness can cause fatigue, lack of endurance, lack of tolerance to heat and cold, etc.
The six groups of nutrients are: Carbohydrates Fats Proteins Vitamins Minerals Water
Carbohydrates include fruits, vegetables, sugar and cereals.
Protein sources include eggs, dairy products, meat, fish, poultry, nuts and peas.
Fat sources include butter, dairy products, meat eggs, nuts, butter, lard, cooking oil, chocolate, mayonnaise, fried foods, and ice cream.
Nutrition
Water makes up 60% of the body.
A sedentary person must replace 2.5 liters per day.
More is needed at altitude, hot weather, or during exertion ( 3 to 4 liters).
Physical Fitness
Important to members of outdoor recreation or rescue groups because their activities can impose unusual physical demands
Important to develop and maintain a high level of physical fitness
Fitness Program
Warm-up
Calisthenics or sports to develop motor fitness
Endurance training to develop cardiovascular fitness
Cool down period
Fitness
The goal and end result of any endurance sport should be to maximize the body’s ability to take up and use oxygen.
Fitness
A good fitness program should aim for a minimum workout of 45 minutes at least 4 times a week.