Harvard.edu - Quickly ascending to a high altitude can challenge the healthiest people, but it can stress individuals with a heart problem, according to the July 2008 Harvard Heart Letter . How your heart will respond to the challenges of high altitude depends on how high you are going, what you plan to do there, the state of your heart, and your overall fitness.

The recent issue of the Harvard Heart Letter describes how high altitude affects these common conditions:

Coronary artery disease - If you’ve had a heart attack, bypass surgery, or angioplasty, and your heart function is good, or you have well-controlled angina, you should be able to handle a high-altitude trip. If you plan to hike, ski, or do another strenuous activity, make sure you are able to do similarly stressful activities at home. Have a stress test to see what kinds of activities you might be able to do and talk with your doctor about whether you might need to change your medications.

Heart failure - High altitude increases blood levels of stress hormones, which are already revved up by heart failure and contribute to its complications. More stress hormones may cause blood pressure to rise excessively. But heart failure need not confine you as long as your condition is stable and you are able to exercise.

High blood pressure - Blood pressure tends to increase at higher elevations, so if you have hypertension it is best to get blood pressure under control before traveling. Bring a blood pressure meter and make a plan with your doctor for changing your medications if your pressure increases.