When you hit the gym you’re not thinking about race or gender, but scientists are. Overall health benefits of exercise depend on sex and race, according to a new study
 reported by Reuters.

Researchers from the University of North Carolina in Chapel Hill compiled data of more than 15,000 middle-aged African-American and Caucasian who have been participating since the late 1980s in a large study about buildup in the arteries (atherosclerosis).  

The study found that exercise decreased harmful triglycerides—but only in Caucasians. In addition, more activity improved artery-clogging LDL cholesterol levels in women—but not in men. Similarly, exercise decreased total cholesterol levels—but only in black women.

Why the differences?

Researchers explained that these findings are mostly new. Though they’re unsure of the reasons, they speculate that hormonal and genetic differences play a part.

“Overall, our results highlight the importance of physical activity on plasma lipid profiles,” researchers said. For example, participants who included weekly mild or moderate exercise showed higher levels of heart-healthy “good” HDL cholesterol.

Learn the best types of exercise for managing diabetes here.