High Altitude Sickness

What Is High Altitude Sickness?

High altitude reaction, also known as altitude sickness and mountain sickness, is strictly a type of high altitude disease. It is a common disease that occurs when the people rapidly enters the altitude of 3,000 meters above sea level and is exposed to low-pressure and low-oxygen environment. In short, when people are mountain climbing, hiking or doing any other activity at al high altitude, their bodies are possible to not get enough oxygen, which can cause high altitude sickness.

Why It Happens?

The occurrence of high altitude sickness is related to the speed of the mountain climbing, altitude, residence time and physical fitness. Generally speaking, when people who live on the plains quickly enter into the plateau above 3,000m above sea level, 50%~75% of people have altitude sickness. But after 3~10 days, they get used to the environment, and the symptoms gradually disappear. In terms of the incidence rate of high altitude sickness, the old is lower that of the young and women are less than that of men. The incidence rate of high altitude sickness is positively correlated with the male body mass index, and has nothing to do with female body mass index, which is indicated that obese men are more susceptible.

Types of High Altitude Sickness

The acute and chronic high altitude sickness are determined by the speed and extent of plateau adaptation. Acute mountain sickness is divided into three types, namely acute altitude sickness, high altitude pulmonary edema, and high altitude cerebral edema. They can cross each other or coexist. Chronic mountain sickness, also known as Monge disease, is rare. It mainly occurs in people who have lived in the plateau for a long time or a few people living above 4,000m above sea level. There are four clinical types of chronic altitude sickness, high altitude polycythemia, high altitude blood pressure changes and high altitude heart disease.

1. Acute high altitude reaction

It is  very common. Unadapted patients develop symptoms within 6 to 24 hours after entering the plateau area within one day, with bilateral forehead pain, palpitations, chest tightness, shortness of breath, anorexia, nausea and vomiting. Symptoms of the central nervous system are similar to those of excessive drinking. In some cases, the lips and nail beds are cyanotic. Symptoms usually resolve after 24 to 48 hours of staying in the plateau, and symptoms disappear after a few days. A small number can develop into high altitude pulmonary edema and (or) high altitude cerebral edema.

2. Chronic high altitude reaction

It is generated by an acute altitude sickness that lasts for more than 3 months and does not disappear. It shows headache, dizziness, insomnia, hypomnesis, inattention, palpitations, shortness of breath, anorexia, dyspepsia, numbness of the hands and feet and facial edema, sometimes arrhythmia or transient fainting.

Symptoms of Altitude Sickness

Typical symptoms include headache, nausea, vomiting and dizziness. Different degrees of altitude sickness have different symptoms. The normal symptoms usually come on within 12 to 24 hours of reaching a higher elevation. But it will disappear within a day or two as your body adjusts to the change in altitude. The normal symptoms include:

  • Headache
  • Dizziness
  • Nausea
  • Vomiting
  • Fatigue and loss of energy
  • Shortness of breath
  • Problems with sleep
  • Less appetite

If you suffer a moderate altitude sickness, you might have:

  • More shortness of breath and fatigue
  • Loss of coordination and trouble walking
  • A severe headache that doesn’t get better with medication
  • A tightening in your chest

If you suffer a severe altitude sickness, you might have:

  • Confusion
  • Shortness of breath even at rest
  • Inability to walk
  • A cough that produces a white or pink frothy substance
  • Coma

Who Gets It?

Anyone can develop altitude sickness, no matter how fit, young or healthy they are. In fact, physical activity at high altitudes makes you more likely get it. The faster you climb to a mountain at a high altitude, the more likely you are to experience altitude sickness. Age, gender and general health status appear to have no effect on the risk of altitude sickness. People who live at low altitudes are not used to high altitudes, and people who have experienced altitude sickness before seem to have a higher risk. Besides, people with lung or heart disease may be told to avoid high altitudes. 

How to Treat It?

Once you have the symptoms of altitude sickness, please tell your tour guide immediately, and don’t go higher. Mild AMS symptoms can be treated with proper medication but if it cannot relieve the symptoms, descend to a lower elevation and go to hospital. Giving pure oxygen can help a person with severe breathing problems caused by high altitude sickness. Please remember do not overuse it in the relatively low altitude if you only get gentle altitude sickness.

How to Prevent It?

Make Adequate Preparation

Before visiting a place at a high altitude, you need to get healthy. If you have heart disease, high blood pressure or other organ problems or anemia should consult a doctor before deciding to travel to a place at a high altitude. Be sure not to catch a cold before you go to a place at a high altitude, or you will get altitude sickness due to physical weakness.

Get Acclimatized

The best way you can lower your chance of getting altitude sickness is through acclimatization, which let your body slowly get used to the changes as you travel to higher elevations. Do not over exert and only partake in light activity immediate after your arrival. Have a good rest during the first one or two days. Don’t use tobacco, alcohol, or other medications, such as sleeping pills. Drink plenty of water and eat carbohydrate food to stay hydrated. Remember the importance of gradual ascent. As long as your travel 1,000m higher, spend a night in this place to make better acclimatize to altitude change.

Medical Treatment

Some medicine can be taken before symptoms appear as a preventive measure. In order to be prepared, you can take the pills days before traveling to Yunnan. These kind of medicines include Rhodiola rosea L, also called Hong Jing Tian in Chinese.

Oxygen Uptake

When traveling in Yunnan, you can buy or rent oxygen tank in many hotels or stores. It can help you feel better.