Not all body fat is created equal. We already know that white and brown adipocytes, or fat cells, are distinct from each other in that white adipocytes store and release lipids while brown adipocytes burn them. But we’re still learning how body fat formation differs from individual to individual based on their diet and exercise regimen. In general, fat tissue in obese adults contains large fat cells, few blood vessels, and a bevy of inflammatory immune cells. Experts have determined that these characteristics intertwine with health complications like insulin resistance and cardiometabolic problems.
But according to a new finding, this typical adipose tissue formation and behavior changes when regular exercise is part of the mix. A new study by researchers at the University of Michigan, published today in the journal Nature Metabolism, demonstrates that in overweight or obese people who exercise regularly, fat tissue structure and composition are “healthier.” How so? Thanks to less collagen and fewer inflammatory white blood cells, it would seem these plus-size exercisers store fat more efficiently than those who don’t routinely work out. This discovery further affirms how breaking a sweat keeps us healthy, even before losing excess bodyweight.
The authors compared fat tissue samples from two groups of people. One group comprised 16 overweight or obese adults who exercised at least 4 times a week for at least 2 years, while the other group of 16 was overweight or obese but sedentary. Their comparisons homed in on the structure and composition of these biopsy samples, accounting for crucial differences like sex, fat mass, and percent body fat of the people who supplied samples.
Fat tissue in the exercise group, the analysis revealed, appeared healthier than fat tissue from the sedentary group. This healthier fat contained more blood vessels, less of a certain type of metabolism-meddling collagen, and fewer inflammatory white blood cells called macrophages. Differences even abounded at the cellular level. Adipocytes from the exercising group boasted more mitochondria and more lipid-storing proteins, as well an a souped-up metabolism.
After comparing adipose, the researchers also cultured lab-grown fat tissue using the biopsied samples. Cultivated tissue from the exercising group could store lipids more efficiently than that of the sedentary group.
Given this, part of exercise’s benefits don’t just come from decreasing the amount of body fat. Exercise actively transforms this tissue into a healthier, more efficient substance, making us healthier in turn.
