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Overweight
Boys Show More Blood Pressure Problems
Among boys, those who weigh more experience a greater increase
in blood pressure under stress, and are slower to return
to normal pressure levels once relaxed, new research reports.
However, in girls, having excess pounds did not increase
the risk of blood pressure problems in response to stress.
It is normal for blood pressure to increase during periods
of stress, but larger and longer increases in blood pressure
can, over time, damage the kidneys, blood vessels and other
organs, study author Dr. Gregory A. Harshfield stated.
"The more load you have on your system the more damage
you have," Harshfield said.
Harshfield, who is based at the Medical College of Georgia
in Atlanta, said he was surprised that stress-related problems
in blood pressure occurred only in overweight boys. Experts
are often more concerned about weight issues in girls, he
noted, because they tend to have more body fat than boys.
However, "even though girls have more weight, the effect
on the cardiovascular system (of being overweight) is greater
in boys," he said.
During the study, published in the journal Hypertension,
Harshfield and his team measured blood pressure changes
in 151 boys and 141 girls of different weights between the
ages of 15 and 18. To determine how their blood pressure
responded to stress, the researchers asked participants
to play a video game with money at stake for one hour.
Along with showing a higher increase and a slower decrease
in blood pressure under stress, boys who weighed more also
tended to rid their bodies of less salt, relative to boys
who weighed less.
Harshfield explained that when blood pressure increases
under stress, the kidneys respond by increasing output in
order to get rid of excess salt. With the salt comes excess
fluid, thereby decreasing the volume of fluid in the blood,
and lowering blood pressure, he noted.
Once again, girls who weighed more were just as able to
excrete salt after a spike in blood pressure as normal weight
girls, the researcher noted, suggesting that something is
"protecting" overweight girls from stress-related
blood pressure problems.
Harshfield explained that the protection may come from the
female hormone estrogen, which blunts the effects of stress
hormones and increases levels of substances that open up
blood vessels.
In contrast, male sex hormones tend to increase the blood
pressure response to stress, perhaps making it "a bigger
problem in boys," Harshfield noted.
He added that many questions remained unanswered, and more
research is needed to better understand the role of stress
in cardiovascular disease linked to obesity.
SOURCE: Hypertension, November 2003.
Article Source: Reuters Health
Article Author: N/A
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