Transcript Meteorological elements and their influence on human health

Meteorological elements and
their influence on human health
Meteorological (climatic)
elements
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temperature,
humidity and precipitation,
sunshine,
wind velocity,
air pressure.
Climate
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The average weather, usually taken
over a 30 year time period, for a
particular region and time period.
It is the average pattern of weather for a
particular region.
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Earth has three climate zones: Polar,
Temperate and Tropical.
Climate zones are further classified into
ecosystems and biomes.
Weather
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Weather consists of the short-term
(minutes to about 15 days) variations of
the atmosphere state.
Microclimate
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Variations of the climate within a given
area, usually influenced by hills,
hollows, structures or proximity to
bodies of water. A microclimate differs
significantly from the general climate of
a region.
Air temperature
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(Also termed surface temperature in
meteorology). The ambient temperature
indicated by a thermometer exposed to
the air but sheltered from direct solar
radiation. The temperature is indicated
by a thermometer placed in an
instrument shelter 1.5 to two meters
above ground. Thermometer is an
instrument for measuring temperature.
Atmospheric pressure
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Atmospheric pressure is defined as the
force per unit area exerted against a
surface by the weight of the air
molecules above that surface.
Atmospheric pressure is measured with
an instrument called a barometer.
Barograph is a recording barometer.
Either daily or week barographs are
used.
Atmospheric pressure
Humidity
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Water vapor content of the air (Some
measure of the water-content of air).
Hygrometers and psychrometers are
instruments used for measuring the water
vapor content in the air.
Absolute humidity
(1) The ratio of the mass of water vapor to the
volume occupied by a mixture of water vapor
and dry air.
(2) Mass of water contained in a unit volume
of moist air.
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Relative humidity
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The (dimensionless) ratio of the actual
vapor pressure of the air to the
saturation vapor pressure. The relative
humidity is usually expressed in per
cent, and can be computed from
psychrometric data.
Relative humidity
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Relative humidity=(absolute humidity:
maximum humidity)x 100%
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Dew point (dew-point temperature)
The temperature to which a given parcel
of air must be cooled at constant
pressure and constant water-vapor
content in order for saturation to occur.
When this temperature is below 0 °C, it
is called the frost point.
In the dew point hygrometer a polished
surface is reduced in temperature until
the water vapour from the atmosphere
forms on it. The temperature on this
dew point enables the relative humidity
of the atmsphere to be calculated.
The wet and dry bulb hygrometer
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In this hygrometer , there are two
thermometers mounted side by side, the
bulb of one being surrounded by
moistened muslin. The thermometer
with the wet bulb will register a lower
temperature than that with the dry bulb
owing to the cooling effect of the
evaporating water. The temperature
difference enables the relative humidity
to be calculated.
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Saturation The condition in which the
partial pressure of any fluid constituent
(water in the atmospheric air) is equal to
its maximum possible partial pressure
under the existing environmental
conditions, such that any increase in the
amount of that constituent will initiate
within it a change to a more condensed
state. Evaporation ceases under such
conditions.
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Evaporation The physical process by
which a liquid or solid substance is
transformed to the gaseous state; the
opposite
of
condensation.
In
meteorology, evaporation usually is
restricted in use to the change of water
from liquid to gas, while sublimation is
used to the change from solid to gas as
well as from gas to solid.
Insolation
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Exposure of an object to the Sun.
Intensity of incoming solar radiation
incident on a unit horizontal surface at a
specific level.
Surface wind
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Wind blowing near the Earth's surface.
Anemometer is an instrument which
measures wind speed or wind speed
and direction.
Surface wind is measured, by
convention, at a height of 10 m above
ground in an area where the distance
between the anemometer and any
obstruction is at least 10 times the
height of the obstruction.
Climate change
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A study dealing with variations in
climate on many different time scales
from decades to millions of years, and
the possible causes of such variations.
Global warming is shorthand for
"climate change”. Climate scientists say
the evidence is strong that humans are
responsible for at least some of the
warming since early in the 20th century.
Greenhouse effect
The sun supplies the energy that keeps the Earth warm
enough for life. Once this energy reaches Earth, it
follows complex paths. Some solar energy is reflected
back into space, while the rest is absorbed by the
atmosphere and the Earth's land and oceans. The
absorbed energy warms the Earth, which in turn
radiates heat back towards space as infrared energy.
Water vapor, carbon dioxide and other greenhouse
gases in the atmosphere absorb some of the outgoing
infrared energy, which heats them. These molecules
then radiate the energy in all directions, including back
to Earth. In effect, some of the energy remains in our
atmosphere, warming the planet. This process is often
called the "greenhouse effect" .
Greenhouse gases
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Carbon dioxide
Water vapour
Methane
Oxides of nitrogen
Ozone
temperature
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T[C]=5(t[F]-32)
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Temperature regulation
Humans and other mammals are homeothermic, able
to maintain a relatively constant internal body
temperature despite widely ranging environmental
temperatures. Although the average human body
temperature is 36.7 degrees Celsius (98.2 degrees
Fahrenheit), this temperature varies depending on
individual differences, time of day, the stage of sleep,
and the ovulatory cycle in women. Thermoregulation is
the balance between heat production mechanisms and
heat loss mechanisms that occur to maintain a constant
body temperature.
Temperature regulation
mechanisms
Heat production
mechanisms are:
 metabolism,
 exercise,
 shivering.
Heat loss mechanisms
divide into passive:
 infrared radiation,
 conduction,
 convection
Active:
 evaporation.
Hypothermia
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or low body temperature, is a result of
prolonged exposure to cold. With a
decrease in body temperature, all
metabolic processes begin to slow.
Hypothermia can be life-threatening.
Stages of Hypothermia in
humans
Stage 1( mild hypothermia) - Body temperature drops
1-2 ° (1.8-3.6 °F, or between 99 - 95 degrees F - mild
shivering occurs. One is unable to perform complex tasks
with hands, shivering may be mild to severe, hands
numb. Blood vessels in outer extremities contract,
lessening heat loss to the outside air. Breathing becomes
quick and shallow. Goose bumps form, to raise body hair
on end in an attempt to create an insulating layer of air
around the body.
Stages of Hypothermia in
humans
Stage 2 - Body temperature drops 2-4 °C (3.6-7.2 °F,
or between 95 - 90 degrees F) - Shivering becomes
more violent. Muscle incoordination becomes
apparent, movements slow and labored, stumbling
pace, mild confusion, but may appear alert. Surface
blood vessels contract further as the body focuses its
remaining resources on keeping the vital organs
warm. Victim becomes pale. Lips, ears, fingers and
toes may become blue.
Stages of Hypothermia in
humans
Stage 3 (severe hypothermia)- Body temperature
drops below approx 32.2 °C (90 °F). Violent shivering
persists, difficulty speaking, sluggish thinking,
amnesia starts to appear, unable to use hands,
stumbling. Cellular metabolic processes shut down.
Below 86 degrees F (28 C) shivering stops, exposed
skin gets blue to puffy, muscle coordination is very
poor, inability to walk appears, incoherent/irrational
behavior turns into stupor, pulse and respiration rates
are much decreased. Major organs fail. Clinical
death occurs.
The donts in hypothermia
Do
not rub or massage the casualty.
Do not give alcohol.
Do not give food or drink (this includes
warm drinks, this is only in extreme cases).
The reason being that blood is diverted
from the major organs where it is needed,
and is sent to the stomach and intestines to
digest the food/liquid, therefore lowering
the core temperature further.)
Do not treat any frostbite.
Do not allow the body to become vertical.
What you should do...
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Call the emergency services.
Get the patient to shelter.
If possible, put the patient in a bath with
medium-temperature water, with the
clothes on; do not do this to an elderly
patient as death may occur as the blood
flows to the surface of the skin
restricting flow to the heart and brain.
What you should do...
Place
hot water bottles in the patient's
armpits and between their legs.
Monitor the patient and be prepared to
give cardio-pulmonary resuscitation.
Remove wet clothing if and only if a dry
change is available.
If in a wilderness environment, remove
wet clothing from the victim and from one
other person. Both individuals should get
into the same sleeping bag if possible, or
wrap in the same blanket, if the sleeping
bag is too small.
Hospital
treatment
hospital, warming is accomplished by
In a
external
techniques (blankets, warming devices) for mild
hypothermia and by more invasive techniques such as
warm intravenous fluids or even (washing) of the bladder,
stomach, chest and abdominal cavities with warmed fluids
for severely hypothermic patients. These patients are at
high risk for arrythmias (irregular heartbeats), and care
must be taken to minimize jostling and other disturbances
until they have been sufficiently warmed, as these
arrhythmias are very difficult to treat while the victim is still
cold. An important tenet of treatment is that a person is
not dead until he/she is warm and dead - remarkable
stories of recovery after prolonged cardiac arrest have
been reported in patients with hypothermia. This is
presumably because the low temperature prevents some
of the cellular damage that occurs when blood flow and
oxygen are lost for an extended period of time.
Frostbite (congelatio)
is the medical condition whereby damage is
caused to skin and other tissues due to extreme
cold. At or below 15°C (59° F), blood vessels
close to the skin start to narrow (constrict). This
helps to preserve core body temperature. In
extreme cold or when the body is exposed to cold
for long periods, this protective strategy can
reduce blood flow in some areas of the body to
dangerously low levels. The combination of cold
temperature and poor blood flow can cause tissue
injury. Frostbite is most likely to happen in body
parts farthest from the heart, and those with a lot
of surface area exposed to cold. These areas
include the toes, fingers, ears and nose.
Symptoms
Generally, frostbite is accompanied with
discoloration of the skin, along with burning
and/or tingling sensations, partial or
complete numbness, and possibly intense
pain. If the nerves and blood vessels have
been severely damaged, gangrene may
follow, and amputation may eventually be
required. If left untreated, frostbitten skin
gradually darkens after a few hours. Skin
destroyed by frostbite is completely black
and looks loose and flayed, as if burnt.
Treatment
Move
the victim to a warm, safe area.
Wrap
the affected areas with dressings and/or
cloths.
Do
NOT rub or massage affected areas.
Place
the affected areas in warm (not hot) water,
until the areas are soft and sensation has
returned.
Wrap
the areas in clean, sterile dressings and
attempt to reach medical help (if necessary).
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If has occurred, treat the hypothermia first.
Medication:
vaccination.
painkillers, anitibiotics, anti-tetanus
Immersion foot/Trench foot
Tissue damage to the foot caused by cold, damp
conditions is called trench foot, immersion foot,
chillblains or pernio. Damage occurs to soft tissue
cell, blood vessels and nerves. Injury may be
temporary or may result in permanent damage
particularly to the nerves of the feet. Trench foot
injuries are sustained in temperatures ranging
from 32-65 degrees Fahrenheit. Trench foot
differs from frostbite in that frostbite is the actual
freezing of cells at or below 32 degrees
Fahrenheit. Another difference between trench
foot and frostbite is that frostbite can easily occur
in the absence of moisture.
Symptoms
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burning and tingling of the feet
loss of sensation
toes appear cyanotic (gray) and blotchy
burning after rewarming
maceration and fissures of the skin
blisters, erythema (redness) peeling
skin
Warm water and tropical
immersion foot
Occur with prolonged exposure to moisture in
folks with excessive perspiration who work in
enclosed rubber boots. Symptoms include painful
thickening and maceration of the skin of the
bottom of the foot. They are most common in
adolescents and young adults. Quite often we'll
see that a person's occupation contributes to
warm water immersion foot. Workers who wear
rubber boots and insulated boots, are most
susceptible to trench foot and warm water
immersion foot. The jungles of Vietnam and
combat boots were a 'shoe in' for tropical
immersion foot.
Treatment
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Limiting exposure to cold.
Use in-shoe foot warmers or tropical L-arginine
cream.
Maintain a dry envirinment inside the shoe.
Rotate your shoes every other day to allow them to
dry thoroughly.
Avoid synthetic materials like rubber or vinyl, wear
leather or cloth that can absorb moisture.
Frequently change the socks to wick away moisture.
Use talc or baby powder daily to wick away moisture.
Hyperhydrosis (excessive perspiration) can be
treated with drying agents (aluminium chloride),
formalin, antihistamine, injections of Botox).
Hyperthermia
a body temperature that is higher than normal.
One example of hyperthermia is fever. A fever is
generally considered to be a body temperature
over 38 degrees Celsius (100.4 degrees
Fahrenheit). A fever is the body's natural defense
to an infection by a bacterium or virus. Fevers are
one of the body's mechanisms for eliminating an
invading organism. Fevers may even make the
immune system work more effectively. Heat
exhaustion and heatstroke are other examples of
hyperthermia. These occur when heat production
exceeds the evaporative capabilities of the
environment. Heatstroke may be fatal if untreated.
Heatstroke
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occurs when the body fails to regulate
its own temperature and body
temperature continues to rise, often to
105° (40.6°) or higher.
Heatstroke is a medical emergency.
Even with immediate treatment, it can
be life-threatening or result in serious,
long-term complications.
Symptoms
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unconsciousness
convulsions
difficulty breathing
rectal temperature over 104°F (40°C)
confusion, restlessness, anxiety
fast heart rate
hot, dry skin (no sweating)
vomiting or diarrhoea
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First aid
Move the person into a cool place.
Remove the person's unnecessary clothing, and place the
person on his or her side to expose as much skin surface
to the air as possible.
Cool the person's entire body by sponging or spraying
cool—not cold—water, and fan the person to lower the
body temperature. Apply ice packs to the groin, neck, and
armpits, where large blood vessels lie close to the skin
surface. Do not immerse the person in an ice bath. Check
the person's rectal temperature frequently, and try to
reduce it to 102.3° (39.1°). Do not give aspirin or
acetaminophen. If the person is awake and alert enough
to swallow, give the person fluids [32 -64 fl oz (1-2 L)]
within the first 2 hours for hydration. However, a person
with heatstroke may have an altered mental status and
may not be able to safely drink fluids without help.
Sunstroke
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Develops after prolonged exposure of
an uncovered head to intense sun
radiation. As a result the blood vessels
inside the skull dilate thus pressing on
the brain tissue.
The symptoms are like in heat stroke
(headache, vomiting, unconsciousness).
First aid- remove the victim to a shelter
protected from sunlight.
Heat exhaustion
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Heat exhaustion is one of the heatrelated syndromes, which range in
severity from mild heat cramps to heat
exhaustion to potentially life-threatening
heatstroke.
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Symptoms include: fainting, nausea,
heavy sweating, rapid, weak heartbeat,
low blood pressure, cool moist skin, lowgrade fever.
Get the person out of the sun and into a
shady or air-conditioned location.
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Heat Cramps
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Heat cramps are muscle contractions,
usually in the muscles at the back of the
calves. These contractions are forceful
and painful.
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These cramps seem to be connected to
heat,
dehydration,
and
poor
conditioning, rather than to lack of salt
or other mineral imbalances. They
usually improve with rest, drinking
water, and a cool environment.
Burns
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1°burn- reddened, painful skin; leaves
no scar, hair and glands will regrow
2°- painful; blisters filled with serum-like
fluid form; leaves no scar, hair and
glands will regrow
3°- tissues under the skin are burnt;it is
anaesthetic as nerves are damaged; it
heals leaving a scar
4°-tissues burn into an ash.
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A-epidermis
B-skin
C-subcutaneous
tissue
Decompression sickness (DCS),
the diver’s disease, the bends,
or caisson disease
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DCS is the name given to a variety of
symptoms suffered by a person exposed
to a reduction in the pressure
surrounding their body. It is a type of
diving hazard and dysbarism.
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DCS is caused by inert gases (mainly
nitrogen), normally dissolved in body
fluids and tissues, to come out of physical
solution and form gaseous bubbles.
Decompression sickness can
happen in any of the following
situations:
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A diver ascends from a dive.
An unpressurized aircraft flies upwards.
The cabin pressurization system of an aircraft fails.
Divers flying in any aircraft shortly after diving.
Pressurized aircraft are not risk-free, since the cabin
pressure is not maintained at sea-level pressure.
A worker comes out of a pressurized caisson, or out of
a mine, which has been pressurized to keep water out.
An astronaut exits a space vehicle to perform an extravehicular activity because the pressure in the space
suit is lower than the pressure in the vehicle.
Predisposing factors
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Magnitude of the pressure reduction: A large pressure reduction is
more likely to cause DCS than a small one.
Repetitive Exposures: Repetitive dives or ascents to altitudes above
18,000 feet within a short period of time (a few hours).
Rate of Ascent: The faster the rate of ascent to altitude, the greater
the risk of developing altitude DCS.
Time at Altitude: The longer the duration of the flight to altitudes of
18,000 feet and above, the greater the risk of altitude DCS.
Age: There are some reports indicating a higher risk of altitude DCS
with increasing age.
Previous Injury: There is some indication that recent joint or limb
injuries may predispose individuals to developing "the bends."
Very cold ambient temperatures may increase the risk of altitude
DCS.
High body fat content increases the risk of altitude DCS.
The after-effects of alcohol consumption increase the susceptibility
to DCS.
Patent foramen ovale in the heart.
Signs and symptoms
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Bubbles can form anywhere in the body, but symptomatic
sensation is most frequently observed in the shoulders,
elbows, knees, and ankles.
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"The bends" (joint pain) accounts for about 60 to 70% of
all altitude DCS cases, with the shoulder being the most
common site. These types are classifed medically as
DCS I.
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Neurological symptoms are present in 10% to 15% of all
DCS cases with headache and visual disturbances the
most common. DCS cases with neurological symptoms
are generally classified as DCS II.
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"The chokes” (shortness of breath, cough) are rare and
occur in less than 2% of all DCS cases.
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Skin manifestations are present in about 10 to 15% of
all DCS cases.
This rash appeared 9 hours after a scuba dive. What is the diagnosis?
1. Decompression sickness
2. Jellyfish envenomation
3. Mycobacterium marinum infection
4. Phylum Porifera contact dermatitis
5. Scombroid fish poisoning
Answer
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Decompression sickness
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Cutis marmorata is a dermal manifestation of
decompression sickness. Initially, there is erythema
accompanied by pruritus, and then the rash spreads
irregularly and deepens in color. It develops a mottled
appearance, with areas of pallor surrounded by
cyanotic patches. During recompression, the rash
resolves.
Treatment
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Recompression is the only effective
treatment for severe DCS, although rest
and oxygen (increasing the percentage of
oxygen in the air being breathed via a
tight fitting oxygen mask) applied to lighter
cases can be effective. Recompression is
normally carried out in a recompression
chamber. In diving, a high-risk alternative
is in-water recompression.
High-Altitude Sickness
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Lack of oxygen causes high-altitude
sickness. As altitude increases, the air
becomes "thinner," which means less
oxygen is in the atmosphere. You get
less oxygen in your lungs with each
breath, so the amount of oxygen in your
blood declines. (This is called hypoxia).
All people can experience mountain
sickness, but it may be more severe in
people who have heart or lung problems.
Symptoms
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Symptoms usually begin within 48 hours of arriving at
high altitude. The higher the altitude, the greater the
effects. People can notice effects when they go to an
altitude of 7,000 to 8,000 feet. If you have heart disease
(such as heart failure) or lung disease (such as
emphysema), you may have symptoms at lower altitudes.
Symptoms include:
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headaches, breathlessness, fatigue
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nausea or vomiting
inability to sleep
swelling of the face, hands and feet.
At very high altitudes, body fluid can leak into the brain
(called brain edema) or into the lungs (pulmonary edema).
Both these conditions can be serious or even lifethreatening.
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Avoidance
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Increase altitude slowly. Climbers and hikers can take
two days to reach 8,000 feet, and then another day for
each 1,000 to 2,000 higher feet. Most people can adjust
or "acclimatize" to the high altitude within a few days.
Here are some tips:
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Avoid strenuous activity for the first day or two.
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Drink extra fluid.
Be careful of drinking alcohol. Its effect is magnified at
high altitude.
Your doctor may prescribe medication to help prevent
or treat altitude sickness.
If you have a heart or lung condition, consult your
physician before going to high altitude. He or she can
tell you whether your condition will let your body adjust
to the lower oxygen in the atmosphere.
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Thank you for your attention!