Exercise can positively change subcutaneous fat tissue and thus improve metabolic health

Exercise can positively change subcutaneous fat tissue and thus improve metabolic health

Exercise is one of the first strategies to treat obesity-related health problems such as type 2 diabetes and other cardiovascular diseases. However, scientists don't understand exactly how it helps improve metabolic health.

To that end, researchers at the University of Michigan studied the effects of three months of exercise on people with obesity and found that exercise can positively change the subcutaneous fat of the abdomen, the fatty tissue just under the skin, in ways that can improve metabolic health—even without weight loss.

Surprisingly, moderate and high-intensity exercise produced the same positive changes in the composition and structure of adipose tissue, and fat cells shrank somewhat even without weight loss, said lead researcher Jeffrey Horowitz, a UM professor of kinesiology.

The results appear in the Journal of Physiology. Co-first authors are UM graduate student Cheehoon Ahn and Ben Ryan, a UM postdoctoral fellow now at the U.S. Army Research Institute of Environmental Medicine.

U of Michigan News · UM kinesiology professor Jeffrey Horowitz on exercise, fat tissue and weight loss

Exercise has changed the appearance and behavior of fatty tissue

The aim of the study was to better understand the effects of exercise on metabolic health in people with obesity. Thirty-six adults with obesity were divided into either a moderate-intensity exercise group (45 minutes, 70% of maximum heart rate) or a high-intensity exercise group (10 one-minute intervals at 90% of maximum heart rate, 60 seconds between low-intensity active recovery).

Blood samples and biopsies of abdominal fat were taken the day after the end of the 12-week sessions and again three days later. There were no exercises between these tests. Results from both exercise groups showed several structural changes in adipose tissue, including slightly smaller and more fat cells, increased collagen type, increased capillary density and changes in proteins that regulate body fat turnover.

Horowitz said that many of the changes in factors that regulate body fat turnover observed one day after exercise were no longer significant by the fourth day of testing, and this underscores the importance of regular, sustained exercise.

The improvements disappeared when training stopped

Many adjustments to exercise training allow a person to train longer or harder, Horowitz said.

However, most of the benefits of exercise that improve metabolic health in people who are at risk of metabolic complications or who have a metabolic disease come from the response to each exercise session - and these responses to exercise are relatively short-lived, often lasting only a year or a few days at most. This is one of the main reasons why it is so important to be physically active most days.”

Jeffrey Horowitz, UM professor of kinesiology

The finding that moderate and high-intensity exercise produce similar responses could be good news for people who prefer to avoid the more demanding high-intensity interval training (HIIT).

Moderate exercise is just as beneficial as HIIT

“Our results suggest that options are open,” Horowitz said. "The similar response between HIIT and more conventional moderate-intensity exercise was one of the bigger surprises for us. It's impressive that despite fairly large differences in exercise stimulus (exercise time, calories burned, intensity) we observed very similar responses between these two exercise programs."

While the results are not related to weight loss, they are related to metabolic health and disease prevention in people with obesity, and these in turn impact quality of life, Horowitz said.

“Although some of our positive results were relatively short-lived, others are longer-lasting, such as adipose tissue capillary density and fat cell structure,” he said. "Therefore, we hypothesize that a physically active lifestyle may help protect people from developing chronic metabolic health complications as they gain weight with age, and there is strong evidence that most of us, even regular exercisers, gain weight as we age." .”

Horowitz said it's important for people to understand that fat tissue is simply where our bodies store extra energy and is not the reason people gain weight.

"Weight gain can only occur when you consume more calories than you burn. And in situations where we gain weight, particularly when people become obese or become overweight, it is ideal to have so-called healthy fat tissue in which to store this extra energy."

Several of the lab's recent studies, and a new five-year NIH-funded project starting soon, focus on understanding how exercise can positively impact adipose tissue to make it a safer haven for fat storage when people are experiencing obesity, weight gain or weight gain.

Source:

University of Michigan

Reference:

Ahn, C., et al. (2022) Exercise remodels subcutaneous adipose tissue in adults with obesity, even in the absence of weight loss. Journal of Physiology. doi.org/10.1113/JP282371.

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