A new study from the University of Michigan reveals that obese people who exercise regularly have better belly fat tissue than obese people who do not exercise. Long-term exercise appears to modify adipose tissue in ways that improve its ability to store fat more effectively, potentially lowering health risks. 

The researchers, led by Jeffrey Horowitz, a professor of movement science at the University of Michigan School of Kinesiology, examined belly fat tissue from two groups: 16 people who exercised at least four times a week for two years or more (the average was 11 years) and 16 people who had never exercised regularly. Both groups were matched in terms of body fat mass, weight, and gender. 

The study discovered significant variations in the adipose tissue of exercisers versus non-exercisers. "Our findings indicate that in addition to being a means to expend calories, exercising regularly for several months to years seems to modify your fat tissue in ways that allow you to store your body fat more healthfully if or when you do experience some weight gain—as nearly everyone does as we get older," Horowitz explained. 

Exercisers' adipose tissue had more blood vessels, mitochondria, and helpful proteins, as well as fewer inflammatory cells and collagen, which can disrupt metabolism. These alterations boost the ability to store fat in subcutaneous adipose tissue, which is the healthiest place to keep it. In contrast, non-exercisers lacked these favourable tissue features. 

Long-term exercise, according to Horowitz, causes fat to store in a healthier location beneath the skin, as opposed to hazardous locations like the organs. He stated: "What it means is that if or when people experience weight gain, this excess fat will be stored more 'healthfully' in this area under the skin, rather than in the fat tissue around their organs (visceral fat) or an accumulation of fat in organs themselves, like the liver or heart." 

The study emphasizes the importance of long-term exercise in preventing diseases caused by fat accumulation in unhealthy environments, such as nonalcoholic fatty liver disease. This disorder, which is common in obese people, can result in serious complications, such as cirrhosis or liver cancer. 

The researchers also generated fat tissue in the lab using cells from both groups. Exercisers' cells transformed into tissue that stored fat more efficiently. Horowitz emphasised the importance of long-term studies to investigate how adipose tissue changes over time with exercise and whether certain types or intensities of exercise produce greater benefits. 

The team now intends to look at how adipose tissue from exercisers and non-exercisers behaves differently and how these distinctions affect general health.