How to Prevent Altitude Sickness

When you travel to high-altitude locations, environmental changes such as temperature drops, increased humidity, stronger UV radiation from the sun, lower air pressure, and reduced oxygen levels can affect you. Altitude sickness is the body's response to lower pressure and changes in oxygen content in the air. This condition typically occurs when you are above 2400 meters. If you think you might experience altitude sickness, follow the tips below to reduce its impact.

Ascend Gradually. When heading to higher altitudes, take it slow. At elevations above 2400 meters, the body generally requires 3-5 days to adjust to the environment. It's recommended to use a device or watch that can measure altitude so you are aware of your current elevation, especially if the area you're exploring lacks altitude markers. These devices can be purchased online or at stores specializing in outdoor gear for activities like mountaineering.

• Avoid certain habits. Do not attempt to climb or ascend to over 2700 meters in one day. Avoid sleeping at locations more than 300-600 meters higher than where you stayed the night before. After reaching 3000 meters, take a rest day to allow your body to acclimate to the new environmental conditions.

Rest. Getting plenty of rest can help you combat altitude sickness. Traveling, whether it's a short or long distance, can disrupt your sleep, leaving you fatigued and dehydrated, both of which increase your chances of experiencing altitude sickness. Therefore, before heading to higher altitudes, take a few days to rest and adjust to the new environment and your sleep routine, especially when traveling abroad.

• Additionally, during the three to five days you spend adjusting to the new altitude, it’s best to dedicate the first one or two days to rest before starting your exploration of the area.

Take preventive medication. Before embarking on your high-altitude adventure, consult a doctor for preventive medication. During the appointment, make sure to inform your doctor of your medical history and let them know that you will be going to altitudes of 2400 to 2700 meters above sea level. If you're not allergic, your doctor may prescribe acetazolamide.

• Acetazolamide is an FDA-approved medication for preventing and treating acute altitude sickness. It is a diuretic that enhances your body's oxygen exchange by improving the gas exchange process.
• Take 125mg of acetazolamide twice a day, starting one day before your trip, and continue for two consecutive days once you reach the highest altitude.

Use dexamethasone. If you're allergic to acetazolamide or your doctor advises against its use, you can try using other non-FDA-approved medications like dexamethasone. Research shows this steroid can reduce both the symptoms and severity of altitude sickness.

• Take the medication as directed by your doctor, usually 4 mg every 6-12 hours, starting one day before your trip and continuing until you fully acclimatize to the highest altitude you reach.
• Taking 600 mg of ibuprofen every 8 hours can help prevent altitude sickness.
• Ginkgo biloba has been studied for its potential to reduce altitude sickness, but the results have been inconsistent, so its use is not recommended.

Check your red blood cell (RBC) count. It may be necessary to get your red blood cells checked before your journey, so make an appointment with your doctor for a blood test. If you have anemia or low red blood cell levels, your doctor may advise treatment for these issues before your trip. This is crucial, as red blood cells are responsible for transporting oxygen to tissues and organs, which is essential for your survival.

• Anemia can be caused by various factors, with iron deficiency being the most common. Vitamin B deficiency can also lead to anemia. Depending on the cause, your doctor may recommend iron or vitamin B supplements.

Buy coca leaves. If you're climbing in Central or South America, you might need coca leaves. Although this is a banned substance in the U.S., the indigenous people of these regions use it to prevent altitude sickness. If you're traveling to these areas, you can purchase some coca leaves to chew on or brew into tea.

• Be aware that drinking a cup of coca tea can cause a positive cocaine test. Coca is a stimulant known to enhance biochemical changes that help your body adapt better to high altitudes.

Stay hydrated. Dehydration will reduce your body’s ability to adjust to higher altitudes. Aim to drink 2-3 liters of water daily, starting well before your departure date. During the climb, it’s important to carry at least 1 liter of water with you. Keep in mind that once you descend, you still need to maintain adequate hydration.

• Avoid alcohol and all alcoholic beverages at least 48 hours before departure. Alcohol can act as a pain reliever, slowing your breathing and contributing to dehydration.
• Stay away from caffeinated drinks like energy drinks or sodas, as caffeine may lead to muscle dehydration.

Eat properly. Certain foods can help reduce the impact of altitude sickness. Research has shown that foods rich in carbohydrates can alleviate altitude sickness symptoms while boosting mood and performance. Studies also suggest that carbohydrates contribute to higher blood oxygen saturation as your body adjusts to altitude. Additionally, consuming carbohydrates improves energy balance. It’s beneficial to consume carbohydrate-rich foods before and during your trek or when heading to higher altitudes.

• Examples of carbohydrate-rich foods include pasta, bread, fruits, and potatoes.
• On the other hand, it’s important to limit salt intake. Excessive salt can lead to dehydration in your body tissues. Therefore, choose foods that either have no salt or contain minimal amounts.
• Physical endurance and strength training may help, but studies show that after a certain altitude, exercise does not significantly reduce altitude sickness.

Different types of altitude sickness. Altitude sickness encompasses three main conditions: acute mountain sickness (AMS), high-altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE).

• Acute mountain sickness occurs due to lower air pressure and oxygen levels.
• High-altitude cerebral edema (HACE) is a severe form of AMS caused by brain swelling, which leads to the dilation and leaking of blood vessels in the brain.
• High-altitude pulmonary edema (HAPE) can develop alongside HACE, after AMS, or 1-4 days after ascending to altitudes above 2400 meters. This condition involves the lungs swelling due to high pressure and constriction of pulmonary blood vessels, causing fluid to accumulate in the lungs.

Identifying Acute Mountain Sickness. Acute mountain sickness is a relatively common condition. It affects 25% of visitors to Colorado’s high-altitude areas above 2400 meters, 50% of tourists trekking the Himalayas, and 85% of those attempting to summit Mount Everest. Various signs and symptoms can signal this illness.

• Headaches lasting 2 to 12 hours, difficulty falling asleep or insomnia, dizziness, fatigue, lightheadedness, increased heart rate, shortness of breath during exertion, and nausea are typical symptoms.

Be Aware of High Altitude Cerebral Edema (HACE). HACE occurs as a severe complication of acute mountain sickness, so it’s crucial to first recognize the symptoms of altitude sickness. As the condition worsens, the symptoms become more noticeable, such as an inability to coordinate movements, meaning you may no longer walk in a straight line, instead staggering or veering off course. You may also experience abnormal psychological symptoms, including drowsiness, confusion, changes in speech, memory, motor skills, thinking, and a loss of focus.

• You could even lose consciousness or fall into a coma.
• What differentiates HACE from acute mountain sickness is its rarity, affecting only 0.1 to 4% of the global population.

Be Cautious of High Altitude Pulmonary Edema (HAPE). HAPE is a more severe form of HACE, meaning you may experience symptoms of both HACE and acute mountain sickness. Since HAPE can occur without transitioning through acute mountain sickness or HACE, you should be vigilant for symptoms such as difficulty breathing or chest pain, increased breathing and heart rate, coughing, and weakness.

• Additionally, physical signs such as bluish or pale lips and fingers may appear.
• Like HACE, HAPE is also a rare condition, affecting between 0.1% and 4% of the global population.

Managing Symptoms. Even with precautions, altitude sickness can still occur. If this happens, it’s important to take action and not let the situation worsen. If you experience acute mountain sickness, wait about 12 hours to see if symptoms improve. During this time, try descending 300 meters to a lower altitude if the symptoms don’t improve or become more severe. If descending isn’t possible, consider using supplemental oxygen and monitor recovery.

• If you show signs or symptoms of HACE or HAPE, immediately descend to a lower altitude and avoid exertion to prevent worsening the condition. Regularly check for signs of improvement.
• If descending isn’t possible due to weather or other obstacles, use supplemental oxygen. Attach the mask and connect the oxygen hose, releasing air. If available, a mobile hyperbaric chamber may be used, potentially eliminating the need to descend if your condition isn’t life-threatening and signs of recovery appear. Hyperbaric chambers are portable devices often carried by rescue teams or found at rescue centers. If possible, contact rescue teams via radio or phone to report your status and location.

Medication Use. In emergency situations, a doctor may prescribe certain medications for acute mountain sickness. These may include acetazolamide or dexamethasone for oral use.

• Your doctor may also prescribe emergency medications for signs of HAPE, including FDA-unapproved drugs for the prevention and treatment of HAPE. Some small studies have indicated that medications like nifedipine (Procardia), salmeterol (Serevent), phosphodiesterase-5 inhibitors (tadalafil, Cialis), and sildenafil (Viagra) could reduce the risk of HAPE if taken within 24 hours before your trip.

• If you begin to experience symptoms of altitude sickness, halt your ascent, especially avoiding sleep at higher altitudes.
• If your condition does not improve after resting, you should descend to a lower altitude.
• If you have certain conditions like arrhythmia, chronic obstructive pulmonary disease (COPD), severe heart failure, coronary artery disease, high blood pressure, pulmonary hypertension, diabetes, or sickle cell disease, you may find your symptoms worsen as you go higher. You might need to consult a doctor or undergo specific training before your trip to ensure your safety. Additionally, if you're on painkillers, you may be more susceptible to illness because these medications can reduce your respiratory rate.
• Pregnant women should avoid sleeping at elevations above 3600 meters.