Why carrying extra kilos makes you less likely to exercise
Jan 01 2017 by Kathy Alvarado
Kravitz had studied Parkinson's before, and when he began to study obesity, the similarities made him think that the reason why obese mice did not move around as much as thin mice could be due to a defect in their dopamine system.
"Other studies have connected dopamine signaling defects to obesity, but majority have looked at reward processing - how animals feel when they eat different foods", Kravitz said.
By week four, the mice with the unhealthy diet spent less time moving and moved much more slowly than the lean mice.
The research also noticed that the excess weight changes our reward-seeking behavior related to physical activities.
Alexxai Kravitz, Ph.D., corresponding author, and investigator with the Eating and Addiction Section, Diabetes, Endocrinology, and Obesity Branch of the NIH, said that while overall good health is linked to exercise, there is not much known about why obese people are less active, Tucson.com reported.
Obese people are often less active, and scientists have discovered that the reason might not just be down to the difficulty of carrying more weight.
For the study, Kravitz and his team fed normal and high-fat diets to mice. "But our findings suggest that assumption doesn't explain the whole story", Kravitz says.
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. This indicates that the extra weight to carry on their bodies was not exclusively responsible for their inactivity.
Around 80 percent of people give up on their resolutions by the second week in February, according to clinical psychologist Joseph Luciani, writing for U.S. News and World Report. The brain chemical dopamine may be a key to the inactivity and obesity in mice.
Similarly, when the researchers "turned up" the receptors in obese mice, they became more active. The results showed that the obese mice had deficits in the D2 dopamine receptor.
"We looked at something simpler: Dopamine is critical for movement, and obesity is associated with a lack of movement", he said.
Health reported Kravitz as saying willpower is a way to modify behavior. "But if we don't understand the underlying physical basis for that behavior, it's hard to say that willpower can solve it".
He believes that studying the physiological causes of why people with obesity move less will reduce the stigma associated with the disease and will help affected people to start losing weight.
A new study published by journal Cell Metabolism has found that in mice, obesity disrupts the proper functioning of dopamine receptor in the brain's striatum.
"Exercise is a healthy thing to do, but its impact on weight has been overstated".