Exercise found to improve the brain function of overweight people
Previous studies had shown that obese and overweight individuals are likely to have insulin resistance in their brains – as well as the rest of their body – where insulin provides information about their current nutritional status. For this study, the researchers wanted to determine whether exercise can improve insulin sensitivity in the brain and also improve cognition in overweight individuals.
The research team, led by Dr. Stephanie Kullman, performed brain scans on 22 sedentary adults who were overweight or obese. These brain scans were done before and after an 8-week exercise intervention that included cycling and walking. An insulin nasal spray was used to measure brain function and insulin sensitivity in the brain. Study participants were also assessed for cognition, mood, and peripheral metabolism.
While the findings showed that the exercise regimen resulted in only marginal weight loss, they also found that brain functions integral to metabolism “normalized” after only 8 weeks. Exercise also led to increased regional blood flow in areas of the brain needed for motor control and reward processes – both of which are dependent on the neurotransmitter dopamine. Given the results, it appears that exercise also improves dopamine-related brain function.
The area of the brain known as the striatum had such an enhanced sensitivity to insulin after the 8-weeks of exercise that the brain response of the study subjects resembled the response of a person with normal weight. Additionally, results showed a correlation between the increased loss of belly fat and a greater improvement in brain function. And participants also reported improved mood and task switching, which indicates improved executive function.
“The bottom line is that exercise improves brain function,” says Kullmann. “And increasing insulin sensitivity in dopamine-related brain regions through exercise may help decrease the risk of a person to develop type 2 diabetes, along with the benefits for mood and cognition.”
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