A study led by scientists at Rutgers University-New Brunswick has found that exercise may directly improve brain function by activating specialized cells involved in how the body responds to insulin.
These findings open the door to new therapies targeting brain insulin action, potentially slowing or preventing the progression of dementia. The study, published in the journal Aging Cell, highlights the link between physical activity, brain health, and insulin sensitivity.
Insulin is a hormone that helps regulate blood sugar levels. When the body becomes less sensitive to insulin—a condition known as insulin resistance—it can lead to various health problems, including type 2 diabetes.
Insulin also plays an important role in brain function, helping neurons communicate effectively and supporting memory and learning processes. When brain cells become resistant to insulin, cognitive functions such as memory, problem-solving, and processing speed may decline.
The research team, led by Steven Malin, an associate professor at Rutgers University, collaborated with the National Institute on Aging to investigate how exercise influences brain insulin sensitivity. Their work focused on neuronal extracellular vesicles, tiny particles released by brain cells.
Once considered cellular waste, these vesicles are now known to transport important proteins between cells, including those involved in insulin signaling. One key protein studied was Akt, which plays a critical role in the body’s response to insulin.
The researchers conducted a two-week trial involving 21 participants with an average age of 60. All participants had prediabetes, a condition where blood sugar levels are higher than normal but not high enough to be classified as diabetes.
Over the course of the study, participants engaged in 12 supervised, 60-minute exercise sessions at moderate to high intensity. Before and after these sessions, they drank a glucose solution, and blood samples were collected to analyze changes in their insulin response.
The results were striking. After the exercise sessions, the number of extracellular vesicles carrying insulin-related proteins increased, especially those containing Akt. This was the first study to demonstrate that exercise directly impacts insulin signaling in the brain through these vesicles.
According to Malin, this indicates that exercise improves the brain’s ability to respond to insulin, which is critical for maintaining healthy cognitive function.
This finding is particularly significant for people with prediabetes or those at risk of developing dementia, including Alzheimer’s disease. Insulin resistance in the brain has been linked to cognitive decline and neurodegenerative diseases. By enhancing the brain’s sensitivity to insulin, exercise may help preserve cognitive abilities and delay the onset of dementia.
Insulin is vital for forming and retrieving memories, maintaining processing speed, and enabling effective communication between brain cells. When brain cells lack insulin, they may become dysfunctional, disrupting these processes.
Malin compared this to playing a game of telephone: if the message is garbled due to insulin resistance, brain communication breaks down, leading to cognitive issues.
Although exercise has long been associated with better brain health, the exact mechanisms have been unclear. This study sheds light on how physical activity improves brain function by enhancing insulin action.
High blood sugar levels, which are common in insulin-resistant individuals, have been shown to impair learning and memory. Exercise reduces blood sugar, which may further support cognitive health.
Malin and his team are now exploring whether a single exercise session can boost the effects of intranasal insulin—a treatment designed to improve cognitive health in aging adults.
If you care about brain health, please read studies about how the Mediterranean diet could protect your brain health, and Omega-3 fats and carotenoid supplements could improve memory.
For more information about brain health, please see recent studies about antioxidants that could help reduce dementia risk, and higher magnesium intake could help benefit brain health.
The research findings can be found in Aging Cell.
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