A new German study finds that, on top of its benefits for general health and mood, exercise can also improve dopamine-related brain function in overweight and obese adults, even before any significant weight loss occurs.
Dopamine is an important neurotransmitter for learning new motor skills and in reward-related learning.
Previous research has shown that people with obesity are prone to insulin resistance in the brain, which can lead to faster cognitive decline. In the new study, researchers from the University of Tübingen in Germany wanted to know whether exercise could improve insulin sensitivity in the brain and therefore boost cognition in overweight individuals.
The researchers observed 22 sedentary adults who were overweight or obese (an average BMI of 31). All of the participants underwent two brain scans before and after an 8-week exercise intervention, including cycling and walking.
Brain function was measured before and after using an insulin nasal spray to measure insulin sensitivity in the brain. Participants were also assessed for cognition, mood, and peripheral metabolism.
Even though the exercise intervention only resulted in marginal weight loss, brain functions important for metabolism “normalized” only after 8-weeks. The findings show that the exercise regimen boosted regional blood flow in areas of the brain important for motor control and reward processes, both of which depend on the neurotransmitter dopamine.
These findings confirm that exercise can significantly improve dopamine-related brain function.
One area in particular, the striatum, showed enhanced sensitivity to insulin after the eight weeks of exercise such that the brain response of a person with obesity after exercise training resembled the response of a person with normal-weight.
Interestingly, the greater the improvement in brain function, the more belly fat a person lost during the course of the exercise intervention. Belly fat has previously been linked to insulin resistance, diabetes, cardiovascular disease and high blood pressure.
Behaviorally, participants reported an improvement in mood and task switching, which is an indicator for improved executive function.
“The bottom line is that exercise improves brain function,” said study leader Dr. Stephanie 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.”