Overweight boys outweigh girls in stress response, s...( NOTE: This release has been updated on...),Health

Overweight boys have greater increases in blood pressure in response to stress than their female peers and decreased ability to restore normal pressures, researchers say in the journal Hypertension.

A Medical College of Georgia study showed that, despite typically having a greater height/weight ratio, overweight girls blood pressures respond less to stress and their natural mechanisms for decreasing blood pressure work significantly better, said Dr. Gregory A. Harshfield, principal author on the paper published online in November and scheduled for the print version in December.

What we observed is that the boys had higher levels of blood pressure throughout, including during stress and recovery, but they did not show an equally greater level of sodium excretion to compensate for higher levels of blood pressure during stress, said Dr. Harshfield. What we are showing is that the mechanisms driving salt-sensitive hypertension are having more impact in males than females, he said, noting that larger studies are needed before reaching any conclusions.

The body naturally responds to stress with an increase in blood pressure, by increasing blood vessel constriction as well as fluid volume inside vessels. The kidneys help with volume by holding onto sodium. Natriuresis is the bodys natural way of eliminating that sodium after the stress is gone to return blood pressure to pre-stress levels.

The study assessed the blood pressure levels of 151 boys and 141 girls ages 15 to 18 during and following stress using a protocol designed by Dr. Harshfield. Subjects were put on a diet for three days to normalize sodium levels. They then came to MCGs Georgia Prevention Institute to participate in the protocol that includes two hours of rest, followed by an hour of playing challenging video games, followed by two more hours of rest.

Blood pressure and sodium excretion were measured throughout the
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Contact: Toni Baker
tbaker@mcg.edu
706-721-4421
Medical College of Georgia
5-Nov-2003