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Harvard Heart Letter | July 2008
Taking heart disease to new heights
With some planning, you can get a Rocky Mountain high even if your heart isn’t in tip-top shape.
Once
upon a time, the only way to get to the top of a mountain was to hike
up. The arduous journey kept all but the healthiest adventurers from
enjoying the world’s loftiest views. Today, autos, buses, cable cars,
cog railways, and helicopters can whisk you from the lowlands to the
highlands without your straining a muscle. Such unprecedented access
means that more people with heart disease are taking high-altitude
trips.
The higher you go, the less oxygen you get with each
breath. The body responds to this in several ways. Breathing becomes
faster and deeper. The heart beats faster and pumps harder. The
sympathetic nervous system pumps more stress hormones into the
bloodstream. Over weeks and months, bone marrow makes more
oxygen-carrying red blood cells, which gradually takes the strain off
the heart and lungs.
Quickly ascending to a high altitude
can challenge the healthiest people. It can spell extra trouble for
individuals with a heart problem. Many physicians, erring on the side
of caution, advise their patients with heart disease to avoid
high-altitude vacations.
Such a wet blanket statement,
while prudent, overlooks creative research into heart disease at high
altitudes. “People with heart disease who can walk, jog, or do other
physical activity at sea level can generally do the same things at
higher elevations, though they might need to take it slower,” says
cardiologist Benjamin D. Levine, a high-altitude expert who directs the
Institute for Exercise and Environmental Medicine at Presbyterian
Hospital of Dallas.
Into thin air
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.
Commercial airliners must
maintain an air pressure equivalent to that at 8,000 feet. So if you
can fly without needing to bring your own supply of oxygen, a passive
trip to Denver — the Mile High City — or Mount Washington in New
Hampshire, both under 6,500 feet, should be fine. But activities more
energetic than oohing and aahing from a scenic overlook, or a
several-day trip to Pikes Peak in Colorado, at 14,000 feet, require
some planning.
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
other strenuous activity, make sure you are able to do similarly
stressful activities at your home elevation with no symptoms. Skiing is
more stressful than many people realize — the heart can easily hit 80%
to 90% of its maximal rate.
Heart failure.
A high-altitude destination poses special challenges for people with
heart failure. It 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. That
said, heart failure needn’t confine you to the lowlands as long as your
condition is stable and you have sufficient left ventricular function
and ability to exercise.
Rhythm disorders.
Exercising at high altitude tends to generate premature contractions
and other harmless arrhythmias. Whether this translates into sustained
trouble isn’t known.
High blood pressure.
Blood pressure tends to increase at higher elevations, so it’s best to
get blood pressure under control before traveling. Bring a blood
pressure meter and work out a plan with your doctor for changing your
medications if your pressure increases.
Pulmonary hypertension.
High altitude can be dangerous for folks with high pressure in the
blood vessels to and from the lungs, many of whom need to bring their
own oxygen when flying. It’s wise to stay below 6,000 feet.
Congenital heart disease. Defects that cause abnormal blood flow from the right side of the heart to the left can pose problems at high altitude.
Travel planning
If
you have your heart set on visiting the Jungfraujoch in the Alps or
Machu Picchu in Peru, you probably can — even if your heart won’t let
you climb it. A travel medicine specialist can determine if you are up
for a high-altitude trip and if you need to take any special
precautions. Here are some things to do before you go:
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Have
a stress test to see what kinds of activities you might be able to do.
Keep in mind that the higher you go, the more your ability to exercise
will decrease, and plan accordingly.
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Talk about whether you might need to change your medications or take new ones at your destination.
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Make sure your blood pressure is stable and under control.
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Accept
the fact that heart attacks and other cardiac problems happen, even at
sea level. If you are headed far from routine medical care, consider
buying travel insurance that includes medical transport.
Then head upward to savor the splendor of the heights.
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