Exercise improves brain function in overweight and obese individuals
July 9, 2019
Science Daily/Society for the Study of Ingestive Behavior
New findings out of the University of Tübingen show that, on top of its benefits for metabolism, mood, and general health, exercise also improves brain function. In recent studies, researchers learned that obese and overweight individuals are prone to insulin resistance in the brain, where it provides information about current nutritional status, as well as the rest of the body. So researchers wanted to know whether exercise can improve insulin sensitivity in the brain and improve cognition in overweight individuals.
In the current study, led by Dr. Stephanie Kullmann, 22 sedentary adults with overweight or obesity (an average BMI of 31) 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 investigate insulin sensitivity of the brain. Participants were also assessed for cognition, mood, and peripheral metabolism.
Even though the exercise intervention only resulted in a marginal weight loss, brain functions important for metabolism "normalized" only after 8-weeks. Exercise increased regional blood flow in areas of the brain important for motor control and reward processes, both of which depend on the neurotransmitter dopamine. Dopamine is an important neurotransmitter for learning new motor skills and in reward-related learning and this research shows that exercise significantly improves dopamine-related brain function. One area in particular, the striatum, had enhanced sensitivity to insulin after the 8-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. 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 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."
https://www.sciencedaily.com/releases/2019/07/190709171815.htm
Exercise gives older men a better brain boost
Men have stronger positive correlation between fitness and brain function
February 13, 2019
Science Daily/American Physiological Society
New research suggests that the relationship between physical and brain fitness varies in older adults by virtue of their sex.
Cardiorespiratory fitness is the measure of how much -- and how well -- oxygen is delivered to the muscles during exercise. Fitness level has also been associated with changes in the brain's nerve-rich tissue, called gray matter, and better cognitive function in later life. Previous studies have also found cardiorespiratory fitness to be related to how the brain functions during periods of rest. Nerve connectivity in the brain during rest changes with age. These changes can negatively affect cognitive function. However, "the neural basis of sex differences in the relationship between fitness and brain function in older adults has not been directly explored," wrote researchers from York University and McGill University in Canada.
The research team studied one group of men and one of women, both with an average age of 67. The volunteers self-reported their typical daily physical activity level. The research team recorded the participants' height, weight, age, sex and resting heart rate to determine their cardiorespiratory fitness. They also administered imaging tests of the brain to record nerve function both within specific brain networks (local efficiency) and among all networks (global efficiency).
The men were found to have higher cardiorespiratory fitness levels than the women. However, the women had higher local network efficiency and lower global network efficiency than the men. This pattern of connectivity was more robust in the women and has been positively associated with executive function, which are skills that contribute to being able to focus, pay attention and manage time. Fitness levels, however, were more strongly associated with improving this brain efficiency pattern for men than women.
"Our findings that [cardiorespiratory fitness] is associated with brain function in a sex-dependent manner underscore the importance of considering sex as a factor when studying associations between exercise and brain health in older adulthood," the researchers wrote.
https://www.sciencedaily.com/releases/2019/02/190213124408.htm