For women, apparently there's nothing like the smell
of a man's sweat.
Researchers at the University
of California at Berkeley said women who sniffed a chemical
found in male sweat experienced elevated levels of an
important hormone, along with higher sexual arousal, faster
heart rate and other effects.
They said the study, published this week in the Journal
of Neuroscience, represents the first direct evidence
that people secrete a scent that influences the hormones
of the opposite sex.
The study focused on androstadienone, considered a male
chemical signal. Previous research had established that
a whiff of it affected women's mood, sexual and physiological
arousal and brain activation. Its impact on hormones was
less clear.
A derivative of testosterone, it is found in male sweat
as well as in saliva and semen. It smells somewhat musky.
"It really tells us that a lot of things can be triggered
by smelling sweat," Claire Wyart, who led the study, said
in an interview on Wednesday.
The researchers measured levels of the hormone cortisol
in the saliva of 48 female undergraduates at Berkeley,
average age of about 21, after the women took 20 sniffs
from a jar of androstadienone. Cortisol is secreted by
the body to help maintain proper arousal and sense of
well-being, respond to stress and other functions.
Cortisol levels in the women who smelled androstadienone
shot up within roughly 15 minutes and stayed elevated
for up to an hour. Consistent with previous research,
the women also reported improved mood, higher sexual arousal,
and had increased blood pressure, heart rate and breathing.
YEAST
For comparison's sake, women also smelled baking yeast,
which did not trigger the same effects.
This was the first time that smelling a specific chemical
secreted by people was shown to affect hormonal levels,
the researchers said. The women had no skin contact with
androstadienone.
The researchers used only heterosexual women in the study
out of concern that homosexual women may respond differently
to this male chemical.
Wyart said while this marked the first time a specific
component of male sweat was demonstrated to influence
women's hormones, other components of sweat may do similar
things.
The study did not determine whether the increase in cortisol
levels triggered mood or arousal changes or whether those
changes themselves caused the cortisol elevation.
The researchers also said their findings suggest a better
way to stimulate cortisol levels in patients who need
it, such as those with Addison's disease. Instead of giving
cortisol in pill form, which has side effects such as
peptic ulcers, osteoporosis, weight gain and mood disorders,
smelling a chemical like androstadienone could be used
to affect cortisol levels, they suggested.
