- New research shows that 8 weeks of exercise can restore healthy insulin activity in the brain.
- Restored insulin sensitivity was also connected to improved metabolism, reduced hunger, and loss of abdominal fat.
- According to the study authors, the findings could help pave the way for therapies to treat obesity and type 2 diabetes.
Insulin resistance occurs when the body is unable to respond to insulin, a hormone produced by the pancreas.
Rather than convert sugar into energy, the cells don’t react, leading to excessive sugar in the blood. The brain’s inability to respond to insulin can negatively impact metabolism and eating habits.
Researchers at DZD, Tübingen University Hospital, and Helmholtz Munich, Germany, explored whether physical activity could positively affect the way the brain and body responded to insulin.
The study, recently published in JCI Insight, found that 8 weeks of exercise improved insulin sensitivity in the brain among adults with obesity.
Excess abdominal fat (visceral adipose tissue) is one of the main risk factors for developing insulin resistance.
“The brain can also become insulin resistant, especially in those with higher belly fat,” study author Stephanie Kullman, PhD, a scientist at the Institute of Diabetes Research and Metabolic Diseases (IDM) of Helmholtz Munich at the University of Tübingen and the Department of Diabetology and Endocrinology at Tübingen University Hospital, told Healthline.
“Brain insulin sensitivity is a predictor if a person is successful at weight loss.”
For the study, researchers observed 14 women and 7 men between the ages of 21 and 59 years with a body mass index (BMI) of 27.5–45.5 for an 8-week period. They used an MRI to measure insulin sensitivity in the brain during pre-endurance training and post-endurance training.
“The 8-week training included aerobic training of 1 hour, 3 times a week. The intensity of the training was based on the individual’s fitness,” Kullman said.
By the study’s end, researchers found that the exercise program restored insulin activity in the part of the brain connected to hunger and satiety to the same level as someone with a healthy BMI.
In addition, improved insulin sensitivity in the brain boosted metabolism, reduced feelings of hunger, and reduced abdominal fat.
According to Kullman, aerobic training improved insulin sensitivity in the brain, which was related to lower feelings of hunger and visceral adipose tissue.
Endurance exercises, like those performed in the study, are effective when it comes to improving insulin resistance.
“Exercise training — both aerobic and resistance training — have been associated with improvements in insulin sensitivity or the responsiveness of cells at absorbing blood sugar,” said Kathryn Starr, PhD, assistant professor in medicine at Duke University and chief scientific officer for Vivo, a virtual personal fitness program for older adults.
“Evidence consistently indicates that 8 weeks of 30 minutes of moderate aerobic exercise at least 3 times a week leads to improvements in insulin sensitivity, and the combination of both aerobic and resistance exercise may lead to even greater improvements,” Starr told Healthline.
Nancy Mitchell, RN, a geriatric nurse, explained that endurance exercises work to keep your heart rate up for prolonged periods, even after a workout.
“[Endurance exercises] usually involve engaging muscles like the heart and those in the lower body,” Mitchell said.
Muscle is highly metabolic tissue because it demands high energy to recover from exercise. That said, you don’t have to go hard on intense endurance exercises to start seeing improvements.
Mitchell added that weighted exercises, swimming, or brisk walking are enough to activate your muscles and elevate your heart rate.
Insulin plays a major role in how the organs and bodily systems function.
“When the brain and body don’t respond to insulin normally, it affects all organs including the brain, muscle, liver, and how we store fat cells,” said Dr. Rekha Kumar, endocrinologist and head of medical affairs at Found, a weight management program.
“When this happens, the pancreas needs to make more insulin in order to metabolize carbohydrates and turns [the] carbs we eat into useful energy. When we make high insulin over long periods of time, we store fat better, particularly abdominal fat,” Kumar added.
Appetite is also affected when a person is insulin resistant.
“Insulin resistance facilitates the accumulation of belly fat and increases food craving, which leads to a vicious cycle of further weight gain,” Kullman said.
Another health concern of insulin resistance is the risk of developing type 2 diabetes.
“In excess, adipose tissue releases pro-inflammatory cytokines and free fatty acids that lead to insulin resistance, impaired glucose handling, and type 2 diabetes,” Starr said.
“Increasing evidence supports a direct detrimental effect of diabetes on muscle quality and performance such that individuals with type 2 diabetes have an increased risk for disability and lower extremity mobility limitations.”
Healthy insulin activity in sedentary adults with obesity can be achieved after 8 weeks of exercise, according to a new study.
The findings also show a link between restored insulin sensitivity and improved metabolism, decreased hunger, and weight loss.
The results are encouraging, which could point health experts toward effective therapies to help treat obesity and type 2 diabetes.
Despite the promising findings, however, study authors noted that more vigorous research is still needed.
If you have obesity and are interested in the many health benefits of exercise, remember that it’s never too late to get started. You may wish to talk with your healthcare professional for more guidance.