discovers effects of exercise in women on HRT
researchers have found that women who take hormone replacement
therapy through a skin patch have higher estrogen levels during
exercise than women who exercise and take HRT orally. The findings,
published in the June issue of the journal Fertility and Sterility,
should help doctors advise their patients about HRT options on
a more individualized basis. There are concerns about a possible
connection between elevated estrogen levels and the development
of certain kinds of cancers.
were wondering whether increased absorption of estrogen from the
patch during exercise could be high enough and prolonged enough
to reach a threshold for concern for increasing the risk of adverse
effects of excessive doses of estrogen such as breast cancer,
said Dr. Christopher Williams, assistant professor of obstetrics
and gynecology at the U.Va. Health
System and principal investigator of the study.
this randomized study, 11 postmenopausal women on standard diets
were given either estrogen pills or estrogen skin patches to take
for one month. After that period, they exercised for 45 minutes
during office visits. At 15-minute intervals during their exercise,
each participant gave blood samples. The samples were tested for
growth hormone, cortisol, insulin, lactate and glucose, plus estradiol
and estrone two potent human estrogens. After four weeks,
participants switched to the alternate form of HRT administration
and repeated the treatment, exercise and blood-sampling regimen.
researchers found that estradiol levels changed significantly
during exercise for the participants using the estrogen patch.
However, the elevated hormone levels returned to normal 30 minutes
after participants finished exercising. The other hormones did
not change significantly during exercise when administered by
the oral or transdermal methods.
estrogen levels increased with exercise in the transdermal estrogen
patch users compared to the oral estrogen users, the
levels stayed elevated for only a short period of time following
exercise, Williams said. It seems unlikely that there
are any increased risks due to elevated levels of estrogen in
active patch users. Perhaps an exception might be women who use
transdermal estrogen patches and have frequent and prolonged exercise,
such as marathon runners or long distance bikers.