When older, overweight people lose belly fat from exercise, a chemical called chemerin in their blood also drops—so chemerin might be a sign that their fat tissue is getting healthier.

When older, overweight people do intense exercise for 12 weeks, a fat-related chemical in their blood called chemerin goes down—and that drop is linked to losing belly fat, better cholesterol numbers, and less insulin being released after eating sugar.

When older overweight people exercise and their blood chemerin drops, their bad fats (cholesterol and triglycerides) also go down—so chemerin might be connected to how the body handles fats.

Exercise makes muscles better at using insulin and the liver produce less sugar—but those improvements don’t match up with changes in chemerin levels, meaning chemerin isn’t the main reason exercise helps insulin work better.

After doing intense exercise for 12 weeks, older overweight people’s pancreases release less insulin right after eating sugar—and that drop matches a drop in a chemical called chemerin, hinting chemerin might tell the pancreas how much insulin to make.