How Altitude Sickness Works

Preventative Treatment

A persistent headache can be a warning sign of altitude sickness.
A persistent headache can be a warning sign of altitude sickness.
©iStockphoto/Diane Diederich

There are some steps you can take to prevent or diminish some of the normal effects of high altitude, as well as more serious conditions, such as AMS, HAPE and HACE.

The best rule of thumb in preventative treatment? If you begin having symptoms, stay put until they disappear. If symptoms get worse, descend. Don't make any sudden changes in altitude -- someone who races up to an elevation of 15,000 feet (4,572 m) will be worse for the wear than someone who slowly acclimates himself or herself to 20,000 feet (6,096 m). If you need to stay at a given elevation, it's better to engage in some light activity than it is to sleep. Generally, your symptoms will worsen as you sleep.

The most important factor in determining your likelihood for altitude sickness is acclimatization. To become acclimated, sleep one night below 10,000 feet (3,048 m) after you begin your ascent. Above 10,000 feet, don't sleep more than 1,000 to 1,500 feet (304.8 to 457.2 m) higher than the elevation at which you previously slept. For every 3,000 feet (914.4 m) gained, sleep two consecutive nights at that altitude. The climbing maxim "climb high, sleep low" refers to the practice of ascending during the day to new heights and then descending at night to sleep. Dehydration is common at high altitudes and can prevent acclimatization. Drink plenty of water before and during your ascent.

There are some drugs you can take to prevent altitude sickness -- and a few that can alleviate mild to moderate symptoms that onset as you ascend.

  • Ibuprofen helps alleviate the pain of normal altitude-related headaches, but it will not affect the underlying causes of the headache. If you treat a headache but it gets worse, descend immediately.
  • Diamox can increase your rate of breathing, leading to increased oxygenation of your blood. It also diminishes symptoms -- especially when you're sleeping. If you're taking it preventively, you should take it a full day before your ascent to allow your body to begin processing it. Like all medications, it may cause side effects and allergic reactions, so you should try it first at low altitude to see if it affects you adversely. In most cases, a careful and cautious rate of ascent will not necessitate the use of Diamox.
  • Acetazolamide or low doses of oral furosemide treats edema in swollen faces, feet and legs [source: Dietz].
  • And speaking of drugs, don't ingest alcohol or any other drug that may alter or decrease your rate of breathing.

Some people are advised to avoid high altitudes altogether. If you have heart disease, lung disease or sickle cell anemia, it's recommended that you not ascend to high altitudes. Diabetics can safely go to high altitudes but must be especially vigilant in monitoring their blood glucose levels -- glucose monitors may be adversely affected by high altitude, and altitude sickness may trigger ketoacidosis (a serious condition caused by a lack of insulin). The CDC recommends that pregnant women shouldn't attempt to go higher than 12,000 feet (3,657.6 m). Researchers don't know whether the effects of altitude sickness can afflict fetuses, but there are concerns that blood vessel leakage could harm them.

If preventative measures fail, you'll need to know how to treat altitude sickness. We'll take a look at some treatments in the next section.