Understanding the Effects of High Altitude
At high altitudes, the air pressure is lower, which means the partial pressure of oxygen is also reduced. This forces the body to work harder to get enough oxygen, leading to increased heart rate and breathing. For most healthy people, the body can acclimate over time. However, for those with pre-existing health conditions, this additional strain can be dangerous, potentially exacerbating underlying illnesses or triggering severe altitude-related medical emergencies. Travel plans should always be made with these risks in mind.
Absolute Medical Contraindications
Certain medical conditions pose such a significant risk at high altitudes that travel should be strictly avoided. The lower oxygen environment can trigger life-threatening complications. These are some of the most critical contraindications identified by health experts:
- Severe pulmonary hypertension: This condition involves high blood pressure in the arteries leading to the lungs. At high altitude, the reduced oxygen levels cause the pulmonary arteries to constrict further, leading to a dangerous increase in pressure. This is an absolute contraindication for altitude travel.
- Sickle cell anemia: The low oxygen can cause red blood cells to deform into a sickle or C-shape, leading to painful and potentially fatal sickle cell crises, blood clots, and organ damage. While individuals with sickle cell trait can often travel with precautions, those with the disease should not.
- Decompensated or severe heart failure: A weakened heart already struggles to pump blood efficiently. The additional stress and increased heart rate caused by high altitude can easily lead to decompensation and life-threatening complications.
- Severe Chronic Obstructive Pulmonary Disease (COPD): Individuals with severe COPD have significantly impaired lung function. High altitude places an impossible burden on their compromised respiratory systems, leading to severe hypoxia and worsening symptoms.
- Severe, uncontrolled asthma: Poorly controlled or unstable asthma can be triggered by the cold, dry air and hypoxia of high altitude, leading to severe and potentially fatal asthma attacks.
- Recent heart attack or stroke: Travel to high altitude is not recommended for at least 90 days after a major cardiovascular event like a heart attack or stroke, as the body needs time to stabilize.
- High-risk pregnancies: While brief trips to moderate altitude may be possible for low-risk pregnancies with a doctor's approval, high-risk pregnancies or sleeping at altitudes above 10,000 feet should be avoided.
- Untreated intracranial lesions: Conditions like cerebral vascular aneurysms or certain brain tumors are considered absolute contraindications due to the risk of increased pressure and rupture from changes in blood flow and pressure at altitude.
Relative Risks and Cautions
For some conditions, travel is not completely forbidden but requires careful consultation with a healthcare provider and specific precautions. These are considered relative contraindications:
- Infants and young children: Infants under six weeks old should avoid altitudes above 8,000 feet, and a more conservative approach is recommended for all young children due to their sensitivity to hypoxia.
- Well-controlled heart or lung disease: Individuals with stable coronary artery disease, mild COPD, or well-managed heart rhythm issues may travel with close medical supervision and a slower ascent.
- Moderate to severe Obstructive Sleep Apnea (OSA): Hypoxia during sleep is a major concern. Individuals with severe OSA should use supplemental oxygen if traveling to high altitudes.
- Diabetes: The management of blood sugar can be more difficult at altitude, and altitude sickness can complicate things further. Careful monitoring is necessary.
- Patent foramen ovale (PFO): This small hole in the heart can increase the risk of high-altitude pulmonary edema (HAPE) and stroke at high altitudes.
Comparing Risk Levels at High Altitude
It is vital to understand the difference between conditions that demand complete avoidance versus those that simply require extra care. This table provides a quick reference, though it is not a substitute for professional medical advice.
| Condition | Risk at High Altitude | Recommendation |
|---|---|---|
| Severe Pulmonary Hypertension | Extremely High | Avoid high altitude completely |
| Sickle Cell Anemia | Extremely High | Avoid high altitude completely |
| Decompensated Heart Failure | Extremely High | Avoid high altitude completely |
| Severe COPD | Extremely High | Avoid high altitude completely |
| Controlled Diabetes | Moderate | Consult doctor, monitor glucose closely |
| Stable Coronary Artery Disease | Moderate | Consult doctor, ascend slowly, limit exertion |
| Mild to Moderate Asthma | Low to Moderate | Consult doctor, carry inhaler, manage triggers |
| Sickle Cell Trait | Low | Stay hydrated, avoid strenuous exercise |
| High-Risk Pregnancy | High | Avoid high altitude completely, or sleep below 10,000ft |
Making an Informed Decision
Before booking a trip to a high-altitude destination, anyone with a pre-existing medical condition should consult a doctor knowledgeable in altitude medicine. A thorough evaluation can help determine your specific risk factors and the necessary precautions, such as a slower ascent schedule, medication adjustments, or the need for supplemental oxygen. Never assume that a previous trip to altitude guarantees safety on a future one, as factors can change.
An essential component of preparation is knowing the nearest medical facilities. The charming and remote nature of many mountain locations often means limited access to advanced medical care. Having an evacuation plan in case of a medical emergency is prudent for all travelers, but particularly those with underlying health concerns. Discussing travel plans with your physician and travel companions is a key step in reducing risk.
This article is for informational purposes and is not a substitute for professional medical advice. For more detailed guidance, always consult with a healthcare provider. For more information on traveler's health, visit the Centers for Disease Control and Prevention at www.cdc.gov/travel.
Conclusion
Understanding who should not go to high altitude is crucial for preventing severe illness and ensuring a safe and enjoyable trip. Individuals with severe conditions like uncontrolled heart disease, pulmonary hypertension, sickle cell anemia, or severe respiratory illness should avoid high altitudes entirely. Others with stable, chronic conditions, or those who are pregnant or with infants, must consult a specialist to understand their specific risks and take appropriate precautions. Prioritizing slow acclimatization, staying hydrated, avoiding heavy exertion, and having a medical plan are universal recommendations that apply to everyone. Ultimately, an informed and cautious approach is the best way to prevent altitude-related complications and have a healthy trip.
