What is altitude sickness?
Altitude sickness or mountain sickness, also called acute mountain sickness (AMS), refers to a group of symptoms occurring on climbing or walking to a higher altitude or elevation too quickly. Since the body is unable to take in enough oxygen, breathing becomes difficult. It can become a medical emergency if ignored.
What causes altitude sickness?
Altitude sickness occurs when a person moves to a higher altitude too quickly. This does not give time to the body to adjust to the low air pressure and low oxygen at high altitudes. The symptoms happen due to low oxygen (hypoxia) in the air and blood causing the blood vessels of the brain to swell (dilate). The dilated blood vessels in the brain may cause headaches and swelling of the brain. The swelling puts pressure on the brain, squeezing it against the skull.
Altitude sickness may rarely advance to a more severe form of the illness called high altitude cerebral edema (HACE). HACE occurs when brain swelling becomes severe manifesting as severe headache, confusion, lethargy, lack of coordination, irritability, vomiting, seizures, coma and eventually death if untreated.
In some cases, the low oxygen causes the lungs to become leaky and accumulate fluid. This is called high altitude pulmonary edema (HAPE). This may cause cough, chest discomfort, pink frothy sputum and heart failure.
Who is at risk for altitude sickness?
Altitude sickness may affect anyone regardless of their age, gender or level of physical fitness. Altitude sickness is directly related to how rapid the climb to high altitude is. It is more likely to occur if the climbs are more difficult and take more strength and energy than with a slow and easy climb.
Some of the factors that determine a person’s risk for altitude sickness are:
- Genetic makeup
- A history of previous altitude sickness
- Residing at an altitude below 3,000 ft
- Presence of respiratory infections or diseases
- A rapid rate of ascent
- Over-exertion before the climb
- Alcohol consumption
- Taking sleeping pills