Why Do Obese People Struggle To Exercise? Scientists Have An Answer

Posted: Dec 31 2016, 3:39am CST | by , in News | Latest Science News

 

Why Do Obese People Struggle to Exercise? Scientists have an Answer
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Starting regular exercise is a common New Year's resolution. Study on mice hint at why many people cannot stick with exercise program for very long

It is widely believed that obesity makes a person inactive and leads to even more weight gain. A new study, however, suggests that there is a relationship between both the aspects but they are connected in a different way than we expect.

According to the new study, obesity changes the chemistry of our brain so dramatically that our natural desire to move around is also suppressed. The study can provides clues about why it may be so hard for many overweight people to stick with an exercise program for very long.

“We know that physical activity is linked to overall good health, but not much is known about why people or animals with obesity are less active,” said lead author Alexxai Kravitz from National Institute of Diabetes and Digestive and Kidney Diseases. “There’s a common belief that obese animals don’t move as much because carrying extra body weight is physically disabling. But our findings suggest that assumption doesn't explain the whole story.”

To understand the whole process, researchers conducted experiments on mice. They fed one group of mice with standard food while gave other a high-fat diet for 18 weeks. The mice that consumed high fat diet showed decreased and much slower movement than that of other group. But the lack of movement began to show even before they gained significant weight, suggesting that excessive weight alone was not responsible for this reduced movement. Researchers hypothesized that altered dopamine receptors triggered inactivity in mice. To their surprise, when they added DR2 receptor in the mice, the obese mice also started to move the same way as the other mice.

“Other studies have connected dopamine signaling defects to obesity, but most of them have looked at reward processing - how animals feel when they eat different foods,” said Kravitz.

“We looked at something simpler: dopamine is critical for movement and obesity is associated with a lack of movement.”

To confirm, researchers inactivated DR2 receptors in lean mice. They found that lean mice too lost the impulse to move or run like the mouse on high-fat diet. They did not however become obese. 

Alexxai Kravitz says. “In many cases, willpower is invoked as a way to modify behavior. But if we don’t understand the underlying physical basis for that behavior, it’s difficult to say that willpower alone can solve it.”

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Hira Bashir covers daily affairs around the world.

 

 

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