Comparing the fat tissue of exercisers and non-exercisers
Researchers from the University of Michigan set up a study to compare the long-term differences between fat storage in people who exercise and people who don’t. They looked at two groups of adults with obesity. The first group included 16 people who reported exercising at least 4x per week for at least 2 years (the average was 11 years). The second included 16 people who never exercised regularly but had similar body fat mass, weight and sex to the people from the first group. The team took samples of belly fat tissue from both groups and analysed them.
Exercisers have healthier fat tissue
The study found that people who do regular endurance exercise, such as cycling, have distinct structural and biological characteristics in their fat tissue that non-exercisers don’t have. Specifically, exercisers have more blood vessels, mitochondria and beneficial proteins, fewer cells that cause inflammation, and less of a type of collagen that can interfere with metabolism.
“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,” said Prof. Jeffrey Horowitz.
Non-exercisers store fat in dangerous places
The study also found that those who exercise have an increased the capacity to store fat under the skin. This is important because the healthiest place to store fat is the subcutaneous adipose tissue, or in other words, the fat under the skin. Increased capacity to store fat reduces the need to store fat in unhealthy places, like around or inside vital organs.
“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,” commented Prof Horowitz.
Fat storage around and inside organs can be a serious health risk. For example, non-alcoholic fatty liver disease, which is common for people with overweight or obesity, is on the rise. If excess fat builds up in the liver, it can cause diseases like cirrhosis, which used to be exclusive to people with alcoholism, plus it increases the risk of cancer.
