Why Exercising as a Teen May Matter for Breast Cancer

Early Start: It’s well established that exercise is one of the best things you can do for your health. But when you start moving may matter just as much as how much you do it. A new study published in Breast Cancer Research suggests that being physically active during the teen years could influence breast health decades later.

The Study: Researchers followed 191 girls ages 11–20, tracking their recreational physical activity alongside several breast cancer–related biomarkers, including breast tissue composition, inflammation, and oxidative stress. Teens who were more active showed healthier markers later on, even after accounting for body fat.

The Takeaway: About 90% of breast cancer cases are linked to non-genetic factors, and lifestyle changes may help prevent roughly a quarter of them. Physical activity can lower estrogen and insulin levels, both of which play a role in cancer development. Building exercise habits early may help set the stage for better long-term health, regardless of weight.

Keep in Mind: This study looked at biomarkers, not actual cancer rates, and focused on Black and Hispanic adolescents. More research is needed to understand how broadly these findings apply across the population.