What is Altitude Sickness?
Altitude sickness occurs when you travel to extreme heights (high altitude) too quickly.
Also known as acute mountain sickness (AMS), this condition can affect people of any gender, age or physical fitness level.
It is the most common type of altitude-related illness. In fact, one survey regarding the famous Himalayas revealed 53 percent of people who failed to ascend at the right pace developed the condition. (1)
High altitude environments are generally harsh. Temperatures and air pressure are lower, ultraviolet radiation increases and humidity stays low.
The most serious danger linked to high altitudes is decreased oxygen (hypoxia).
Partial pressure of oxygen (PO2) measures how much has dissolved into your blood. At 3,000 meters above sea level, your PO2 will be approximately 69 percent of what it is at sea level.
The lower air pressure and oxygen content at high altitudes is what causes the medical condition.
Our bodies are fairly adaptable to these changes. The average person can eventually acclimatize to an environment with moderately low oxygen.
However, this process is not immediate. It does take an average of three to five days for the body to get used to a high altitude.
Acclimatization can help reduce the chances of altitude sickness. Taking time to ascend slowly allows your body to get used to the new environment and can improve your overall well-being.
Altitude sickness will present a risk at heights of over 2,500 meters. Genetics can play a role in your chances of contracting the condition too. (2)
It is also important to avoid respiratory depressants at high altitudes. These are substances that impact your ability to breathe, such as alcohol. (3)
The symptoms of altitude sickness can be described as follows:
A headache is one of the key identifying symptoms of altitude sickness.
You might experience a headache two to 12 hours after arriving at a high altitude. It usually manifests during or right after your first night of sleep.
With mild altitude sickness, your headache may disappear after you acclimatize to the high elevation. This can take 12 to 48 hours. (4)
However, a headache which gets progressively worse can indicate high altitude cerebral edema (HACE), an advanced form of altitude sickness. (5)
Fatigue is another common symptom of altitude sickness. You will feel more lethargic or weaker than usual.
If altitude sickness progresses untreated, you can begin to feel exhausted therefore it should not be taken lightly. (6)
Nausea or Vomiting
Coughing and Shortness of Breath
Coughing can be a symptom of high altitude pulmonary edema (HAPE). This is a severe progression of altitude sickness.
If you are coughing up blood, alert your travel companions and descend to a lower altitude as soon as possible.
Feeling breathless even while you are resting is another warning sign of HAPE. (8)
Cyanosis is when your skin develops a blue tinge from oxygen deprivation. Mucus membranes, such as your lips and eyelids may also turn blue. (9)
This is a sign of advancing HAPE. If you present with cyanosis, you will require urgent medical intervention if rapid descent is not possible. (10)
HACE affects your brain through a buildup of fluid. This can cause you to behave abnormally.
You may experience confusion or even hallucinate. Your ability to make sound judgments may also become impaired. (11)
Altitude sickness can manifest in three different forms, two of which are severe.
Every individual can react to altitude sickness differently.
If you notice symptoms of mild altitude sickness, you have a risk of developing a more serious syndrome. (12)
The types of altitude sickness are as follows:
Acute Mountain Sickness (AMS)
Acute mountain sickness (AMS) is the least serious form of altitude sickness. The symptoms generally mimic those of a hangover.
You will likely experience nausea, headache and feel fatigued. AMS can differ in intensity depending on the person.
Some individuals may be incapacitated by AMS while others may only experience mild sickness. (13)
High Altitude Cerebral Edema (HACE)
HACE is a severe form of altitude sickness, extending from AMS. It results in an build up of fluid on the brain.
An early warning sign of HACE is a worsening headache. You may also have trouble speaking and behave irrationally.
The exact physiological mechanism behind HACE is not completely understood. It is believed to be provoked by very low levels of oxygen at high altitudes. (14)
An individual with HACE may become drowsy and lose consciousness. This syndrome can lead to death due to brain herniation.
Herniation occurs If the brain continues to swell. Eventually, it presses against your skull and the pressure cuts off blood supply to your brain. This could lead to fatal consequences. (15)
High Altitude Pulmonary Edema (HAPE)
HAPE is just as severe as HACE, the difference being is that it causes fluid to accumulate in your lungs.
This syndrome is heralded by the incapability to breath normally even when you are resting. If you are breathless even without exerting yourself, take it seriously because it can indicate HAPE. (16)
As it progresses, you may become feverish or develop a cough. At advanced stages, this cough can be accompanied by frothy pink saliva.
HAPE is caused by the low oxygen levels at high altitudes. The veins and arteries in your lungs constrict and the alveoli (air sacs) in your lungs become impaired.
The alveoli then begin to fill with fluid from the blood vessels instead of air. HAPE is the leading cause of death due to high altitude. (17)
Altitude sickness is suspected when you feel unwell at altitudes above 2,500 meters.
It is important that you and your traveling companions are aware of the telltale signs of altitude sickness before ascending. (18)
If you are showing any typical symptoms of the illness, do not continue your ascent. Stay at the altitude you are currently at and take time to rest for one or two days to see if your symptoms subside.
Make sure you inform your companions you are feeling ill. If your altitude sickness progresses into HACE, you may suffer from impaired judgment.
The optimal treatment for severe altitude sickness (HAPE and HACE) is to descend as soon as possible. (19)
The treatments for altitude sickness include:
Over the counter analgesics can help to relieve some symptoms of acute mountain sickness (AMS). You can take analgesics to relieve your headache.
Acetazolamide is used both as a preventative and a treatment. The drug acidifies your blood, improving oxygen transport in your arteries.
If it is taken before you ascend, it can help your body adapt to the higher altitude at a faster rate.
If you are already affected by altitude sickness, acetazolamide can alleviate your symptoms. (20)
Dexamethasone is a steroid used to treat high altitude cerebral edema (HACE). This drug is commonly used to treat other types of cerebral edema.
It is usually administered when descending to a lower altitude is not immediately possible.
It can also be taken as a preventative measure against AMS and HAPE. (21)
Supplementary oxygen is used to temporarily treat HACE and HAPE.
Bottled oxygen can reduce risk of death from these syndromes while you are transferred to a lower altitude. (22)
What is altitude sickness? Altitude sickness is a condition resulting from ascending to great heights too quickly.
What are the signs of altitude sickness? The symptoms of altitude sickness can include headache, fatigue and nausea. It can also cause vomiting, coughing, cyanosis and irrational behavior.
How do you develop altitude sickness? The illness develops when you travel to elevated heights without giving your body a chance to acclimatize. Oxygen levels deplete the further away from sea level you go and it takes time for your body to adapt.
What is the best treatment for altitude sickness? Treatments for altitude sickness vary depending on the case. They can include: over the counter analgesics, acetazolamide, dexamethasone or oxygen. If your symptoms are severe, you will have to descend to a lower altitude.
What are the long term complications of altitude sickness? HAPE and HACE can require hospitalization if severe. (23)
Is altitude sickness considered a disability? Altitude sickness does not fit the definition of a disability. Although it can be dangerous, it is not a chronic, mental or physical impairment. (24)
Is there any cure for altitude sickness? Altitude sickness can usually be resolved by descending to a lower altitude. However, depending on how serious your condition is, you may also require medical intervention or other treatments. (25)
Is altitude sickness life threatening? Both HAPE and HACE can be fatal if you do not receive immediate treatment. (26)
As far as altitude sickness is concerned, both prevention and preparation are key. Therefore if you are traveling to elevated heights, it is critical you can identify the symptoms.
If untreated, the condition can be fatal. Therefore the sooner complications such as HACE and HAPE are caught, the better your prognosis will be.
Even mild symptoms of altitude sickness should not be taken lightly. It is risky and also irresponsible to continue ascending further if you are feeling unwell. Therefore, do not be afraid to speak up and make your group aware.
To reduce the chances of altitude sickness, allow your body enough time to get used to the levels of ascent.