FOR IMMEDIATE RELEASE
March 18, 2009
Contact: Christine Guilfoy
Office: (301) 634-7253
cguilfoy@the-aps.org
Symposium to Look at Genetic Basis of
Exercise
Research could one day shed light
on muscle diseases
 BETHESDA,
Md. (Mar. 18, 2009) ‘Adaptation to exercise’ is a familiar phenomenon,
even if the phrase is not: A sedentary person takes up jogging and can
barely make it around the block. After jogging regularly for a few weeks,
the person can jog a mile, then two, then three. With regular exercise, the
body adapts, becoming fitter and more efficient. The heart can pump more
blood, delivering more oxygen to the muscles. The muscles get stronger, and
so on.
There are individual differences in the ability to
adapt to exercise. Some sedentary individuals who take up jogging will be
able to run three miles after a short training period, while others will
take much longer to get to the same level. What accounts for this difference
in a person’s ability to adapt to exercise? One important factor is our
genes.
Research into the role genes play in exercise has been
gaining steam over the past few decades and is the topic of a symposium at
the Experimental Biology conference in New Orleans on April 20. Mark
Olfert of the University of California at San Diego and Claude Bouchard of
the Pennington Biomedical Research Center have organized the symposium, the
Genetics of the Adaptation to Exercise. The American Physiological
Society is sponsoring the symposium.
Speakers at the symposium will include Eric Hoffman of
the Children’s National Medical Center, Washington, D.C. and Tuomo Rankinen
of the Pennington Biomedical Research Center. Dr. Hoffman will discuss
Genetics and skeletal muscle adaptation to exercise, while Dr. Rankinen
will talk on Genetics and the response to exercise in human populations.
The symposium will also include presentation of selected abstracts.
Focus on individual genes
So far, scientists have identified about 200 genes that
play a role in the body’s ability to adapt to exercise. Although the
research includes the term ‘exercise’ this work extends well beyond athletic
performance. For example, it will lead to greater knowledge of how the
muscles work, and to understanding muscle diseases such as muscular
dystrophy.
Some of the research into the genetics of exercise has
focused on individual genes. Dr. Olfert has looked at thrombospondin, a gene
that limits the growth of small blood vessels, known as capillaries, in the
muscles. Removing the gene allows greater capillary growth. The more
capillaries in the muscle, the more oxygen the muscle will have available
during exercise.
In one study, Olfert compared sedentary mice that did
not have the thrombospondin gene in their skeletal muscle to mice that did
have the gene. He found the mice without the thrombospondin, as expected,
could exercise at a much greater capacity compared to the normal sedentary
mice with the gene. What’s more, the mice without thrombospondin could
exercise at almost the same level as the mice with thrombospondin that
exercised regularly.
Multi-gene approach
While this research is exciting, it has its
limitations, Dr. Olfert said. Many genes play a role in exercise adaptation,
most of these genes probably have a minor effect, and the way these genes
work and interact with each other is quite complicated.
Dr. Bouchard has focused his research on gene patterns,
using the power of computing to sift through thousands of genes. He has been
involved with the Heritage Family Study, which began in 1992. In this
program, family members undertake a standard exercise program while
researchers measure changes in maximal oxygen uptake (a measure of aerobic
fitness), blood pressure and glucose and insulin metabolism.
The researchers compared measures of adaptation to
exercise on individuals within families and between families on a variety of
measures, including maximum oxygen uptake. Because families share a similar
genetic makeup, the research has helped uncover the role that genetics plays
in exercise. For example, the researchers calculated that 25-50% of the
variation in increase in maximum oxygen uptake was due to heredity.
They also found that one gene, the FHL-1 gene, played
an important role in determining an individual’s insulin sensitivity and
glucose disposal ability in response to exercise. This gene, like other
genes, comes in different variants. Individuals with one variant of this
gene improved their insulin sensitivity and glucose disposal ability with
exercise while people with another variant did not. This helps explain why
some people who exercise are better at improving their glycemic level in the
blood and avoiding diabetes, Dr. Bouchard said.
The research will have implications not just for those
of us who are healthy, but for those of us whose genes make it hard to get
the full benefits of exercise.
Editor’s Notes: To arrange an interview with Dr.
Olfert or Dr. Bouchard, please contact Christine Guilfoy at
cguilfoy@the-aps.org or (301) 634-7253.
A fuller audio interview with them is available in
Episode 19 of the APS podcast, Life Lines, at
www.lifelines.tv. More information on the symposium is available at:
http://www.the-aps.org/meetings/eb09/abs/eep-bouchard.htm.
Physiology is the study of how
molecules, cells, tissues and organs function to create health or disease.
The American Physiological Society (APS) has been an integral part of this
scientific discovery process since it was established in 1887.
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