SUNDAY, May 18 (HealthDay News) -- Flying on commercial flights
may put people who suffer from obstructive sleep apnea at greater
risk of cardiac stress, Australian researchers report.
Sleep apnea is a common condition in which breathing stops or
becomes very shallow. Obstructive sleep apnea is the most common
form of the condition. When it occurs, people can't get enough air
through their mouth or nose, and the levels of oxygen in the blood
may drop.
"Falls in oxygen in flight are important but may not be the only
important change that occurs," said lead researcher Leigh Seccombe,
a senior scientist in the Department of Thoracic Medicine at
Concord Repatriation General Hospital in Sydney. "They may not be
the only factor separating normal subjects from those with
obstructive sleep apnea."
People with obstructive sleep apnea clearly have increased
metabolic demands during air travel, Seccombe said. "For many who
have heart or other vascular disease, this may place them at
increased risk of cardiac events such as heart attack or
arrhythmia, but the extent of that risk is uncertain," she
said.
Seccombe said the researchers performed the study, because
obstructive sleep apnea is becoming much more common as obesity
increases. The findings were expected to be presented Sunday at the
American Thoracic Society's 2008 International Conference, in
Toronto.
For the study, Seccombe's team compared oxygen levels and
breathing patterns in healthy people and 22 people with severe
obstructive sleep apnea during a simulated flight. The simulator
replicated the oxygen and pressure levels found in the passenger
cabin during commercial airline flights.
The researchers found that people with obstructive sleep apnea
had lower levels of oxygen in their blood before and during the
simulated flight. They also found that those with obstructive sleep
apnea increased their breathing intensity at about the same rate as
healthy people during the simulation.
However, while it's normal for the rate of breathing to increase
as air pressure falls, people with obstructive sleep apnea
experienced higher heart rates and more demand for oxygen, compared
with healthy people, the researchers found.
"Half of the patients with obstructive sleep apnea would require
supplemental oxygen in-flight if current guidelines for those with
lung disease were strictly followed if these results are typical,"
Seccombe said. "In patients with obstructive sleep apnea or other
cardiac or vascular disease, it might be wise to have a lower
threshold for giving supplemental oxygen until more results are
available."
Dr. Ronald D. Chervin, who's with the Michael S. Aldrich Sleep
Disorders Laboratory at the University of Michigan, said he agreed
that people with obstructive sleep apnea have a greater risk for
heart problems during long airline flights, though there has been
little research on the topic.
"I suspect that part of the problem may arise from co-morbid
conditions, and especially obesity, which can compromise
ventilation and perhaps account for some of the investigators'
findings of differences between groups," Chervin said.
More information
To learn more about sleep apnea, visit the
U.S. National Library of Medicine.
