Altitude sickness occurs in low atmospheric pressure conditions and not necessarily in low oxygen conditions at sea level pressure.
Although treatable to some extent by the administration of oxygen, most of the symptoms do not appear to be caused by low oxygen, but rather by the low CO2 levels causing a rise in blood pH.
The percentage of oxygen in air remains essentially constant with altitude at 21% up until 21330 Ft.
Air pressure (and therefore the number of oxygen molecules) drops as altitude increases - consequently, the available amount of oxygen to sustain mental and physical alertness decreases above 3050 meters.
Altitude sickness usually does not affect persons traveling in aircraft because modern aircraft passenger compartments are pressurized at an air pressure equivalent to an altitude of 2440 meters.
High altitude can be defined as an altitude where there is a increase in atmospheric pressure leading to lower oxygen molecules in air.
Temp ↑se ↔ Air expand ↔ Pressure↓se
Temp ↓se ↔ Air dense ↔ Pressure↑se
Normal physiologic changes occur at high altitudes
Hyperventilation (breathing faster, deeper or both)
Shortness of breath during exertion
Changed breathing pattern at night
Awakening frequently at night
Types of High Altitude Illness
Acute Mountain Sickness (AMS)
High Altitude Pulmonary Edema (HAPE) - affects the Lungs
High Altitude Cerebral Edema (HACE) - affects the Brain
AMS (Acute Mountain Sickness)
The condition indicates that your body is not being acclimatized to its current altitude.
An "ideal" altitude where your body is in balance; most likely is the last elevation at which you slept.
Headache is a primary symptom of altitude sickness, but headache can also be due to dehydration
Headache occurring at an altitude above 2400 meters combined with one or more of the following symptoms, can indicate altitude sickness
Lack of appetite, nausea, or vomiting
Fatigue or weakness
Dizziness or light-headedness
Pins and needles
Shortness of breath upon exertion
Persistent rapid pulse
Peripheral edema (swelling of hands, feet, face)
HAPE (High Altitude Pulmonary Edema)
This is an another form of severe altitude that results in fluid in the lungs.
It often occurs with AMS, it is not felt to be related and the classic signs of AMS may be absent.
Breathlessness at rest
Fast, shallow breathing
Cough, possibly productive of frothy or pink sputum
Gurgling or rattling breaths
Chest tightness, fullness, or congestion
Blue or gray lips or fingernails
HACE (High Altitude Cerebral Edema)
Mountain sickness can be from mild to life-threatening. At the "severely ill" end is a condition called HACE; this is when the brain swells and ceases to function properly.
HACE can progress rapidly, and can be fatal in a matter of a few hours to one or two days.
Persons with this illness are often confused, and may not recognize that they are ill.
Headache that does not respond to analgesics
Gradual loss of consciousness
HADE (High Altitude Dumb Edema)
HADE causes temporary intelligence loss due to reduced oxygen in the blood supplying the brain. Unlike HACE and HAPE, HADE often occurs at modest altitudes and can be artificially induced even at sea level by drinking too much beer.
Hypothermia is a result of low body temperature caused by cold ambient temperature; the most common cause of death in the wilderness.
- Jigna Modh