EMBARGOED
FOR RELEASE UNTIL
August 8, 2007
APS Contact
Donna Krupa
Office:
(301) 634-7253
Cell: (703) 967-2751
dkrupa@the-aps.org
Cardio Exercise Benefits In
Male Vs. Female Hearts
Study
conducted in an animal model
Austin, TX – While cardiovascular disease occurs
in both men and women, it does not affect them in the same way. Risk factors
and protective factors for heart diseases are likewise unequal. The
molecular mechanisms responsible for these differences are so far unknown,
but some believe it is due to chromosomal linked genes or sexual hormones
such as estrogen and testosterone. While the mechanisms behind the
differences are unknown, the physiological differences are clear. A new
study examining chronic exercise in male and female mice finds that moderate
long-term exercise provokes a sex-dependent cardiac adaptation that is
different for females versus males. The findings may eventually help improve
treatment strategies for women and men with heart disease.
The study is entitled “Voluntary Exercise Induces
Sex-Specific Physiological Cardiac Remodeling.” It was conduced by Sebastian
Brokat, Kathleen Cantow, Nadine Ehrenberg, Arne Kuhne, Jenny Thomas, and
Vera Regitz-Zagrosek, all of the Center for Cardiovascular Research in
Berlin, Germany. Dr. Brokat will discuss his team’s findings at the upcoming
conference, Sex and Gender in Cardiovascular-Renal Physiology and
Pathophysiology, being held August 9-12, 2007 at the Hyatt Regency
Austin on Town Lake in Austin, TX. The meeting is the second scientific
event to be sponsored by the American Physiological Society (APS;
www.The-APS.org) this year.
Background
Exercise is an important factor in preventing
cardiovascular disease. Frequent exercise leads to the physiological
remodeling (change) and hypertrophy (beneficial enlargement) of the heart.
This type of hypertrophy is different from pathological hypertrophy (an
abnormal enlargement that leads to problems such as heart failure).
Pathological hypertrophy is also irreversible. There have been several
descriptions on the effects of estradiol and testosterone (female and male
hormones, respectively) on pathologic hypertrophy, but very little research
has been conducted on the physiological remodeling of the heart.
Methodology
In this study, the researchers focused on chronic
voluntary exercise, an important factor which protects the heart against
cardiovascular diseases. The researchers observed the voluntary exercise
(using a running wheel) of both male and female mice during the course of 5½
weeks. They also held a control group of mice under the same conditions, but
without the exercise wheel. Each mouse's daily distance, time, and average
speed were recorded. Their hearts were monitored using an echocardiograph to
better evaluate any cardiac changes during the course of the study. They
also isolated and analyzed the RNA of each mouse to look at any changes at
the molecular level.
Results
The researchers found that the female mice:
-
showed a much higher level of exercise performance (9.2
km/d vs. 6.4 km/d)
-
had a greater increase in LV mass (15 percent vs. five
percent of left ventricular hypertrophy) compared to their sex-matched
sedentary controls
-
experienced a 20 percent decrease in the protein that
promotes cell function while there were no changes in males
-
decreased β/α–MHC ratio by 41 percent while the males
experienced no change
Conclusions
According to Dr. Brokat, the lead researcher, “This
study finds that exercise appears to help females more than males. The
findings bring us a step closer to explaining the sex bias in physical
activity that protects the heart.”
***
The
American Physiological Society (APS;
www.The-APS.org) has been an integral part of the scientific discovery
process since it was established in 1887. Physiology is the study of
how molecules, cells, tissues and organs function to create health or
disease.
# # #
NOTE TO EDITORS: The APS meeting is being held
August 9-12, 2007 at the Hyatt Regency Austin on Town Lake, Austin, TX.
Members of the media are invited to attend the sessions. To schedule an
interview with Dr. Brokat, please contact Donna Krupa at 301.634.7209
(direct dial), 703.967.2751 (cell) or
DKrupa@the-APS.org.
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