Stress Underlies Heart Attacks
Stress you didn't even know you had
could kill you, U.S. researchers reported.
They found people whose blood pressure
rose during "mental stress" were six times more likely to have
a heart attack or other severe heart event within six years than
people who handled the stress more calmly.
And it was not stress that people
knew they were feeling -- pulse was not affected and their volunteers
usually had no idea their blood pressure was spiking, the researchers
told a meeting of the American Heart Association in Orlando.
"How do you learn to manage something
when you don't know you have it?" asked Diane Becker of Johns
Hopkins University in Baltimore, who led the study.
The mental stress reaction trumped
everything else. Other risk factors such as smoking, having high
cholesterol, diabetes or being a man paled in comparison, the
"People with hyper-reactive blood
pressure to mental stress were more than six times as likely to
have a coronary heart disease event," they said.
They tested 295 siblings who were
under 60 but already had some signs of coronary artery disease.
They tested this with an angiograph, which measures the thickness
of an artery.
Many had not known they had early
signs of heart disease.
They gave them a stress test during
which they measured pulse and blood pressure, and then watched
them for six years.
An "event" was defined as a heart
attack, severe chest pain known as angina or a 50 percent or more
blockage of an artery.
Hyper-reactive people were those
in the upper 25 percent of reaction, as defined by how much their
blood pressure went up. The "hot" responders saw, on average,
a 20 point rise in blood pressure during the stress test.
TEST THAT ANNOYS EVERYONE
The test was one that stresses
most people, at least consciously, said Becker.
Words such as "red," "green" or
"blue" are displayed on a computer screen. The background is in
one color, the letters themselves are written in another, often
a color not matching the word, and sometimes other distracting
colors are thrown on the screen.
The colors and words change. "You
are told to identify the color in the written word," Becker said.
"It is very confusing. If you don't get it correct, it sends you
a message that says 'wrong'," she added.
"The more you get right, the faster
it goes, so you can never master it."
Becker said she could hear volunteers
swearing at the screen as they took the test. Their pulse and
blood pressure was monitored continuously.
Afterward, the volunteers rated
how much stress they felt.
"There was no relationship between
people's perception of stress and their actual mental stress,"
She believes the effect has to
do with the sympathetic nervous system, which controls blood pressure
and other nonconscious bodily functions. A hormone called catecholamine,
which is related to adrenaline, may be the direct cause although
she says more study is needed.
Becker hopes to identify the gene
or genes responsible. Perhaps a blood test could be developed
to warn those most at risk.
And while some studies have strongly
linked hostility with heart disease, others have had mixed results.
Becker believes conscious stress
and biological stress may be two different things.
"People's capacity to tell you
that they are stressed is worth about nothing," she said. "We
would see people with hideous responses who say they are fine."
Reference Source 89