In this post, we aim to give you some essential facts about the symptoms for altitude sickness, to help protect you from getting seriously ill on a trip at Lhasa’s high elevation. We want to give you an idea of how bad the symptoms are, and how they might impact your trip to Tibet. You will learn about the three main types of altitude sickness and their symptoms. You will also learn some very simple rules that every traveler to Lhasa should know to stay healthy at high altitude.
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What are the Chances of Getting Seriously Ill or Dying?
A very common fear about altitude sickness is that it will ruin your trip or, at worst, kill you.
- The bad news: people do get seriously ill and die from altitude sickness in Tibet
- The good news: while there is no way to guarantee that you won’t get altitude sickness, there is a lot you can do to protect yourself from the most serious outcomes, which are rare.
The US Centers for Disease Control and Prevention (US CDC) says it this way:
“Since the onset of symptoms and the clinical course are sufficiently slow and predictable, there is no reason for anyone to die from altitude illness, unless trapped by weather or geography in a situation in which descent is impossible.”
The US CDC recommends three simple rules to prevent death or severe illness:
- Know the early symptoms of altitude illness, and be willing to acknowledge when they are present.
- Never ascend to sleep at a higher altitude when experiencing symptoms of altitude illness, no matter how minor they seem.
- Descend if the symptoms become worse while resting at the same altitude.
What are the Symptoms for Altitude Sickness?
There are three main forms of altitude sickness, and we’ll look at the symptoms for each below, as well as at your body’s normal reaction to traveling to high altitude.
- Normal reactions to high altitude
- AMS – Acute Mountain Sickness
- HACE – High-altitude cerebral edema, a life-threatening swelling of the brain with fluid
- HAPE – High-altitude pulmonary edema, a life-threatening accumulation of water in the lungs
Normal Physical Reactions to High Altitude
You should know that not all the “symptoms” you get when you travel to altitude are considered altitude sickness. According to the International Society for Mountain Medicine (ISMM), the normal changes you can expect are:
- Hyperventilation (breathing faster or deeper than normal, or both)
- Shortness of breath during exertion
- Changed breathing pattern at night
- Awakening frequently at night
- Increased urination
If these are not symptoms of mountain sickness, what are?
Symptoms of AMS/Acute Mountain Sickness
AMS symptoms range from mild to life-threatening. On the mild end of the scale, there are a cluster of symptoms that usually start 2-24 hours after arrival at an altitude over about 8000 feet/2500 meters and usually begin to decrease after about 3 days.
Headache, along with:
- dizziness or light headedness
- shortness of breath
- loss of appetite
- difficulty sleeping
- general feeling of malaise
At a mild level, the symptoms are often described as similar to an alcohol hangover or having the flu. A mild AMS headache can be treated with pain medications or Diamox, an altitude sickness medicine that we discuss more in another post in this series called How to Avoid Altitude Sickness.
While mild AMS is quite common and is generally not debilitating, it is important to take it seriously. As the ISMM notes, “It is remarkable how many people mistakenly believe that a headache at altitude is “normal”; it is not… be willing to admit that you have altitude illness, that’s the first step to staying out of trouble.”
What to do if you have Mild AMS
- Stay at the same elevation until your symptoms resolve
- Let your travel companions and guide know about your symptoms
- Watch yourself and others for early warning signs that the AMS has progressed, or for HACE or HAPE.
It is rare for the symptoms to progress to life-threatening, but once you have identified AMS in someone, it is important to watch for the development of symptoms that might lead to High Altitude Cerebral Edema (HACE), which is at the severe end of the AMS range.
The great majority of people who get HACE ignored the rule against ascending with symptoms of AMS.
A Typical Scenario of AMS Developing in a Trekker
Symptoms of HACE
As altitude sickness progresses, the brain can swell and stop working well, due to HACE, High Altitude Cerebral Edema. HACE, is rare, but can progress rapidly, and can be fatal in a matter of a few hours to one or two days. It is is important to recognize the symptoms and signs of HACE early and to get the subject to lower altitude immediately.
According to the Lake Louis Consensus on the Definition of Altitude Sickness, HACE can be considered “end stage” or severe AMS. The symptoms can show in one of two ways:
- A person with the symptoms of AMS will also develop one or both of the following:
- Loss of physical coordination (ataxia)
- A change in mental status, such as confusion or disorientation
- A person with no previous symptoms of AMS will develop both of the following:
- Loss of physical coordination (ataxia)
- A change in mental status, such as confusion or disorientation
As HACE worsens, symptoms may include:
It’s important to note that a characteristic sign of HACE is a decreased ability to think and loss of physical coordination. A person ill with HACE will likely be confused, and unable to understand that she or he is in danger.
Warning Signs of HACE
Some warning signs to look for, especially if the traveler has shown symptoms of AMS:
- Splitting headache that is not relieved by medication
- Nausea and vomiting (or increased nausea and vomiting)
- Increasing weakness and fatigue and decreased activity (The person or people is excessively tired/lethargic and is dragging far behind everyone else.)
- Shortness of breath
- Loss of coordination, perhaps an unsteady walk, developing into a staggering walk as if the person is drunk. As a test, have the person by having them walk a straight line. Draw a straight line on the ground and ask the sick person to walk the line, with one foot just in front of the other, heel to toe. If s/he cannot do this with relative ease, you can presume the person has HACE.
- Confusion or disorientation
What to Do if You See Signs or Symptoms of HACE
You must take immediate action to get the person to a lower elevation, hopefully at least 2,000 – 4,000 feet / ~ 600 – 1,200 meters, but even a few hundred feet (~ 100 meters) may help. You do not want to leave it until the person’s illness progresses to the point to which she or he cannot walk at all. Often HACE happens at night, but you cannot wait until morning as delay can be fatal. It is recommended to descend to the last point at which the traveler woke up feeling well, without AMS. (We don’t really discuss treatments in this series of posts about altitude sickness, since we want to focus on knowledge and prevention, but you can learn more in the links in the Resources section below.
Symptoms of HAPE
High Altitude Pulmonary Edema, or HAPE, is a dangerous accumulation of fluid in the lungs. Like HACE, it is a severe form of altitude sickness, but unlike HACE, it is not considered to be a severe form of AMS. People with HAPE often also have AMS, but it is possible to have HAPE without the signs of AMS. According to the Lake Louis Consensus on the Definition of Altitude Sickness definition a person with HAPE will have:
At least two of these symptoms:
- Difficulty breathing at rest
- weakness or decreased exercise performance
- chest tightness or congestion
At least two of these signs:
- crackles or wheezing in at least one lung field
- central cyanosis (bluish or purple discoloration of the lips, tongue and mouth, that is often accompanied with peripheral cyanosis, a blueness which can be seen in the fingernail beds.)
- tachypnea (abnormally fast breathing)
- tachycardia (abnormally fast heart rate)
Warning Signs of HAPE
To look for:
- Increasing breathlessness on exertion leading to shortness of breath even at rest
- Cough, which possibly produces pink or frothy sputum
- Extreme fatigue
- Sounds of gurgling, rattling, wheezing, or crackling when breathing
- Fast, shallow breathing
- Feelings of fullness, tightness, or congestion in the chest
- Gray, blue or purple lips or fingernails.
HAPE commonly occurs on the second night after an ascent.
What to Do if You See Signs or Symptoms of HAPE
It is important to know that HAPE can be even more rapidly fatal than HACE. On first realizing that the traveler may have early signs of HAPE, immediate descent is critical. It is far better to descend while the traveler is still mobile rather than waiting for severe symptoms that would force the victim to be carried. Learn more about treatment of HAPE in the links in the Resources section below.)
A Typical Scenario of HAPE Developing in a Trekker
HAPE can be confused with other respiratory conditions, like bronchitis, a high altitude cough, pneumonia, or asthma. See this post by the International Society for Mountain Medicine (ISMM) for specific recommendations, particularly if you are an asthmatic.
What to Take Away from this Post
Many travelers to Tibet will experience mild AMS, but as the ISMM notes, “there is no reason people should die from AMS.” The great majority of problems comes when people with AMS continue to ascend. “This simply cannot be emphasized too much. If you have symptoms of AMS, do not ascend any higher. Violating this simple rule has resulted in many tragic deaths.” (ISMM website)
At the beginning of this post, we showed you three simple rules that the US Centers for Disease Control and Prevention recommend to prevent death or severe illness at high altitude, and here now, we will leave you with the well-known “Golden Rules” of altitude sickness, originally formulated by Dr. David Shlim at the CIWEC Clinic in Kathmandu.
The Golden Rules of Altitude Sickness
More Posts in this Series on Altitude Sickness in Tibet
- What is my Risk of Getting High Altitude Sickness?
- How to Avoid Altitude Sickness
- Itineraries in Tibet for Preventing Altitude Sickness
You Might Also Like:
Best 100 Tibet Travel Tips: The Ultimate Guide
- The U.S. Centers for Disease Control and Prevention’s CDC Health Information for the International Traveler, chapter on altitude sickness
- International Society for Mountain Medicine ISMM
- Himalayan Rescue Association Nepal
- Princeton University Outdoor Action Guide to High Altitude: Acclimatization and Illnesses
- US National Institutes of Health National Library of Medicine
- Everest.net on Altitude Sickness
- Altitude.org on Altitude Sickness
- WikiVoyage Beta page on Altitude Sickness