Harvard Health Letters

Q. Some friends invited me to accompany them to Rocky Mountain National Park. I'd love to go, but I have high blood pressure and worry that high altitudes are dangerous for people with this condition. Is that the case?

A. If you have high blood pressure but are otherwise healthy, your blood pressure is under control, and you take some precautions, a trip to the Rocky Mountains should be fine.

The higher you travel, the less oxygen you take in with each breath. The body responds by increasing the heart rate and the amount of blood pumped with each beat. This temporarily increases blood pressure until the body adapts to the lower oxygen level, usually within a couple of days.

The rule of thumb for spending time at a higher altitude is to go no higher than 8,000 feet in the first leg of the trip, and stay there for at least one night. After that, go up no more than 2,000 feet at a time, with an overnight stay between each ascent. For your trip, I would suggest spending a few days in Granby or Estes Park, two of the "gateways" to the park. Both are at elevations just under 8,000 feet.

Take it easy for a day or two before doing any strenuous hiking or other activity. Pay attention to how you feel. If you are feeling fine, go a couple thousand feet higher each day. Take your blood pressure and other medicines, drink plenty of water, and pay attention to your body.

About one-quarter of people who rapidly travel to 8,000 feet experience some symptoms of mountain sickness. These include headache, nausea, fatigue, and difficulty sleeping. They usually disappear as the body gets used to the higher elevation. If they continue or get worse, or if you find yourself short of breath at rest, become confused, or have trouble walking in a straight line, immediately seek medical attention. A rapid descent, oxygen, and specific medications may be necessary if this occurs.

Doctors once routinely advised people with high blood pressure, coronary artery disease, prior bypass surgery or angioplasty, heart failure, and other cardiovascular conditions not to go to high altitudes. But this advice wasn't based on much evidence. With the growing population of active, relatively fit people with hypertension or other cardiovascular problems who want to ski, hike, or even just sightsee at elevation, there is increasing evidence that, with a gradual ascent, most shouldn't be kept from experiencing the grandeur of the mountains.

High altitudes can be dangerous for people with severe lung diseases (especially pulmonary hypertension) or with unstable cardiac diseases. Some data also suggest that individuals with patent foramen ovale (an opening between the right and left atria) are at increased risk of having fluid accumulate in the lungs (high altitude pulmonary edema).

Talk to your doctor before ascending if you have one of these conditions. But for those with stable, controlled cardiovascular disease, a small but growing body of evidence suggests that they should be able to go to 12,000 feet or so without a problem. When I talk with a patient about going to higher altitudes, the main thing I want to know is if his or her condition is stable and generally under control. If so, a trip to the mountains may be just what the doctor ordered.

-- N. Stuart Harris, M.D., Assistant Professor of Surgery, Harvard Medical School; Chief, Division of Wilderness Medicine, Massachusetts General Hospital

 

 

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