Different brain biology may explain why some
people tend to be couch potatoes while others
are more active.
That's the conclusion of a U.S. study that found
some brains may naturally encourage restless behaviors
that burn calories and help control weight.
Researchers found that the brains of rats bred
to be lean are more sensitive to a chemical produced
in the brain called orexin A. This chemical stimulates
appetite and spontaneous movement such as fidgeting
and other minor unconscious movements.
The study also found that the lean rats had a
far greater expression of orexin receptors in
an area of the brain called the hypothalamus,
compared to rats bred to be obese.
"The greater expression of orexin receptors
suggests the lean rats' brains were more sensitive
to the orexin the brain produces. The results
point to a biological basis for being a couch
potato," senior researcher Catherine M. Kotz,
of the VA Medical Center, University of Minnesota,
and the Minnesota Obesity Center, said in a prepared
statement.
She said this line of research suggests that
frequent unconscious movement, such as fidgeting,
may burn calories and help control weight. It
also suggests a possible new way to control weight
and could lead to the development of drugs to
stimulate minor physical activity.
The study was published in the online edition
of the American Journal of Physiology-Regulatory,
Integrative and Comparative Physiology.
