Published: March 31, 2003

The University Colorado at Boulder's kinesiology and applied physiology department is seeking healthy postmenopausal women 45 to 65 years old to participate in research involving hormone replacement therapy, or HRT.

The goal is to test and see if estrogen and/or moderate exercise may improve body functions, said Associate Research Professor Kerrie Moreau of the kinesiology and applied physiology department.

Specifically, the researchers are interested in determining if three different types of HRT and/or endurance exercise like walking can improve the function of women's arteries, hearts and nervous systems by reducing levels of "oxidative stress." Oxidative stress is the exposure of one's body cells to molecules that are generated continuously in human bodies as a function of normal metabolism.

But such molecules also can produce damage to cells and interfere with normal body functions. Advancing age and menopause generally are associated with an increase in artery stiffness in women, which can have negative effects on health including blood-pressure increases. The levels of oxidative stress also increase with age.

"Hormone replacement is a controversial topic right now," said Moreau, principal investigator of the HRT study at CU-Boulder. "But we are looking at three different types of estrogen replacement therapy. Because progesterone has been thought to negate the beneficial effects of estrogen, we will use a cyclic, natural progesterone therapy every two months in women who have a uterus instead of the daily medroxyprogesterone acetate that has been most widely used in clinical trials.

"We hope that we will be able to identify which estrogen has greater potential benefits and possibly those that don't - only with regard to the cardiovascular and nervous system. Moreover, we will be looking at the combined effects of HRT and exercise on eliciting benefits."

The study will take place at the General Clinical Research Center located in CU-Boulder's Wardenburg Heath Center. Opened in 2001 and funded by the National Institutes of Health, the center is a multi-million dollar venture. It is a satellite facility of the University of Colorado Health Sciences Center's Adult General Clinical Research Center in Denver.

The CU-Boulder researchers are testing a theory that levels of oxidative stress will decrease by taking HRT and by participating in a walking exercise program. The regimen is predicted to decrease stiffness of the arteries. The researchers also believe the effects may be different depending on the different kinds of HRT used in the study.

Participants will begin with five testing sessions at the Wardenburg facility. They then will randomly be given either a placebo or a type of HRT for the next six months. After the first three months, they will be asked to return to the lab four times to repeat some of the tests and see if HRT has improved their health.

After the second three months, participants will be in a 12-week, home-based walking program, returning to Wardenburg's General Clinical Research Center every two weeks to monitor their progress through additional tests.

Women participating in the trials will be financially compensated for their time. For more information or to sign up for the research study, call (303) 492-3010.