Recreational exercise associated with breast tissue composition and stress biomarkers during a critical developmental window.
A new study from Columbia University Mailman School of Public Health and the Herbert Irving Comprehensive Cancer Center suggests that recreational physical activity (RPA) during adolescence may influence breast tissue composition and stress-related biomarkers—factors linked to future breast cancer risk.
Researchers found that girls who engaged in at least two hours of recreational physical activity in the previous week had lower breast tissue water content (an indicator of lower breast density) and lower levels of urinary stress biomarkers compared with girls who reported no activity. These associations were independent of body fat and mirror findings in adult women, where higher physical activity is linked to lower breast density and reduced breast cancer risk.
The study included adolescent girls (average age 16), most of whom were Hispanic or Black/African American, drawn from a long-running urban birth cohort in New York City. Notably, more than half of participants reported no recreational physical activity in the past week.
The authors emphasize that adolescence is a critical window for breast development and that physical activity during this period may shape biological pathways relevant to later breast cancer risk. They call for longitudinal studies to determine whether these biomarker changes translate into lower cancer risk and highlight the importance of promoting physical activity early in life, especially in historically underrepresented and higher-risk populations.