Endurance exercise can help the body store healthier fat

• Regular endurance exercise can improve the health of the fat-storing subcutaneous adipose tissue directly beneath the skin, says a new study from the University of Michigan.
• This is particularly important for people with overweight and obesity, as this type of tissue can develop abnormalities that can, in turn, lead to a range of serious health issues, including insulin resistance and metabolic conditions.
• The new study finds that adipose tissue from people who have engaged in endurance exercise for more than 2 years is more likely to have more fat-storing blood vessels and an expanded capacity for storing lipids.

Regular endurance exercise can maintain health in the subcutaneous adipose tissue in which fat is stored, says a new study from the University of Michigan.

The study, which appears in Nature Metabolism, found that adipose tissue samples taken from regular endurance exercisers with overweight or obesity exhibited key differences compared to similar cell samples from people with overweight or obesity who did not exercise. These differences mean that the adipose tissue of regular exercisers is capable of storing fat in a healthier manner.

The study notes that metabolic abnormalities in the adipose tissue of people with overweight or obesity have been linked to various health complications.

Such abnormalities include capillary scarcity, pro-inflammatory macrophage infiltration, and changes in metabolic function, including dysregulated lipid (fat) metabolism.

Issues such as these may limit storage capacity, pushing fat into systemic circulation. It may find its way into organs such as skeletal muscle and the liver — a driver of whole-body insulin resistance — or cause local and systemic inflammation and other obesity-related conditions.

The researchers who conducted the recent study recruited 52 adults with overweight or obesity, 24 of whom were classified as exercisers for over 2 years, and 28 as nonexercisers.

From this group, a subset of participants was also selected, which included 16 exercisers and 16 sedentary individuals. Each group was composed of eight males and eight females. Participants in this subgroup were closely matched for body fat percentage and fat mass, and were “very similar” in age, body weight, and body mass index.

Samples of subcutaneous adipose tissue were taken and analyzed from all individuals.

The researchers found that adipose tissue from exercisers exhibited increased angiogenesis — more blood vessels — higher lipogenic storage capacity, beneficial proteins, mitochondria, and a reduction in a form of collagen that can interfere with metabolism and cause inflammation.

In addition to the subgroup, adipose cells from the original larger group — minus the subgroup members — were examined ex vivo. This confirmed an enhanced capability for angiogenesis and lipid storage among exercisers.

The finding could also mean that should a person who exercises gain weight, as most people do as they age, the fat stored in adipose tissue may find a healthier environment in which to reside.

Fat in the human body is, broadly speaking, stored in three places: Just under the skin in subcutaneous adipose tissue, in visceral or abdominal fat cells deep inside the body that may surround the organs, and inside the organs themselves.

Of these three locations, subcutaneous adipose tissue is generally considered the most benign.

Speaking to Medical News Today, Jason Ng, MD, who teaches endocrinology and metabolism in the Department of Medicine at the University of Pittsburgh and who was not involved in this study, explained that:

“Subcutaneous adipose tissue is right under the skin, and can usually be pinched by someone on the belly. Subcutaneous adipose tissue can help store lipids and triglycerides, which can help maintain good metabolic regulation.“

“Subcutaneous adipose tissue,” added Ng, “can have different effects on the body depending upon the location of the adipose tissue, with some adipose tissue depots working to increase insulin sensitivity and reduce insulin resistance, for example.”

In contrast, he pointed out, “visceral fat tissue is known to generate inflammation leading to insulin resistance and eventually diabetes.”

Mir Ali, MD, a board-certified bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, who was likewise not involved in the study, further explained for MNT that:

“The way somebody[‘s body] distributes fat is really determined primarily genetically, and there are some general considerations. Men tend to deposit fat more around the middle of the belly, women tend to be more on the hips, but, it’s really something you can’t change.”

Ng cited various factors that can cause a person to gain fat as they age.

“As you get older, you generally replace muscle mass with fat mass, hormonal changes such as menopause in women for example, and generally less physical activity, and dietary reasons. All of these can contribute to weight gain as we age,” he pointed out.

“There’s a popular belief,” said Ali, “that if you do a lot of sit-ups you’re going to get rid of fat around the belly, but it just doesn’t work that way.”

However, he explained: “You lose fat all around, and if you deposit more fat in your belly you’ll notice more fat loss if you’re losing weight in the belly, but it doesn’t necessarily mean that any particular exercise or thing can direct where the body loses fat.”

“Fat cells have the capacity to stretch and gain in size,” said Ali, “but they don’t really go away unless you remove fat cells.” Ali noted that while some surgeries, such as liposuction, do remove fat, a person cannot get rid of it altogether, nor should they.

“A normal body has fat cells,” he said. “So when patients go up and down in weight, they deposit the fat back in the cells they have, and then as they lose weight they burn that fat off, but the fat cells don’t go away.”