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UNTIL 12:01 AM EST
Thursday,
September 25, 2008
Contact: Donna Krupa
Office: (301) 634-7209
Newsroom Phone: 843-681-0794 or 95
Cell: 703-967-2751
dkrupa@the-aps.org
For
Overweight Patients With Insulin Sensitivity, Even One Session Of Exercise
Can Improve Metabolic Health
  HILTON
HEAD, SC—One out of every three Americans is obese. These
individuals are at greater risk for additional diseases, since obesity
leads to other health problems, such as diabetes.
Obesity-related complications are associated with an
abnormal fat metabolism in the muscle. As a result, accumulated fat
by-products inside the muscle affect insulin resistance. To avoid the build
up of fat by-products, fat must either be oxidized (burned, as in exercise)
or stored (as benign fat) in muscle.
A team of researchers has examined the effect of
exercise on fat accumulation in a new study involving five obese women. In
one session the women overate and did not exercise; in a follow-on session
they overate and did exercise. The researchers found that:
the body’s fat-burning oxidation rate was reduced after one
day of overeating;
conversely, just one session of exercise increased the rate of
fat-burning oxidation; and
exercise increased the amount of fat that would eventually be
stored in the muscle.
The findings indicate that even one bout of exercise
helps to reduce the fat by-products inside the muscle, which affects the
insulin sensitivity. The findings also suggest that a single session of
exercise “steers” muscle fat towards oxidation, thereby avoiding the
accumulation of fat by-products.
The study was conducted by Andrea Cornford, Minghua Li,
Simon Schenk, Matthew Harber and Jeffrey Horowitz, Division of Kinesiology,
University of Michigan, Ann Arbor. Their research is entitled "Alteration in
Lipid Metabolism After One Day of Overeating Are Reversed by a Single
Session of Exercise.” They will present their findings at a meeting
sponsored by the American Physiological Society (APS;
www.The-APS.org). The conference, The Integrative Biology of
Exercise V, will be held September 24-27, 2008 in Hilton Head,
SC.
Study Summary
The aim of the study was to assess changes in fatty
acid (FA) metabolism in response to acute overeating and exercise. Five
obese women performed three separate two-day trials in which they consumed
(1) a weight-maintaining diet [Control]; (2) a hypercaloric diet (700
calories above normal); and (3) the same hypercaloric diet, but exercised to
the point where they expended the 700 excess calories.
The morning after each trial, researchers measured
whole-body FA oxidation [FAO] and calculated non-oxidative FA disposal as
the difference between FA uptake and FAO.
A muscle biopsy was performed to measure the presences
of triglycerides that are involved in fat storage.
The morning after the trials, the researchers observed
that overeating suppressed fatty acid oxidation below the control levels,
while exercising increased oxidation. Non-oxidative FA disposal was the same
in each trial and a direct correlation between FA uptake and muscle GPAT
activity were found.
Conclusions
According to Andrea Cornford, a member of the research
team, “Exercise decreases everyone’s insulin resistance and therefore
reduces the chances of developing diseases such as type 2 diabetes. This
study shows that even a single bout of exercise helps obese individuals
increase their body’s fat-burning rate and improve their metabolic health.”
*******
Physiology is the study of how molecules, cells, tissues and organs
function to create health or disease. The American Physiological Society (APS;
www.The-APS.org/press) has been an integral part of this discovery
process since it was established in 1887.
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NOTE TO EDITORS: The APS Conference, The
Integrative Biology of Exercise V, is being held September 24-27, 2008
in Hilton Head, SC. Members of the media are invited to attend. To register,
or to schedule an interview with the research team, please contact Donna
Krupa at 301.634.7209 (office), 703.967.2751 (cell) or
DKrupa@the-APS.org. There will be an APS newsroom onsite.
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