WEDNESDAY, Nov. 5, 2025 (HealthDay News) -- For digestive system cancers (DSCs), higher physical activity levels are associated with lower risk and mortality, according to a study published online Oct. 30 in JAMA Oncology.Yiwen Zhang, Ph.D., from the Harvard T.H. Chan School of Public Health in Boston, and colleagues examined the association between physical activity and DSC risk and mortality with a focus on the optimal amount and long-term consistency. The study included data from the Health Professionals Follow-Up Study, the Nurses' Health Study, and the Nurses' Health Study II.A total of 6,538 incident DSCs and 3,791 DSC deaths were documented among 231,067 men and women during up to 32 years of follow-up. The researchers found that higher physical activity levels were associated with lower DSC risk and mortality (≥45 versus <3 metabolic-equivalent task [MET] hours/week; hazard ratios, 0.83 and 0.72, respectively). The inverse associations were seen for digestive tract and accessory organ cancers (hazard ratios for ≥45 versus <3 MET hours/week: 0.85 and 0.73, respectively). The lowest DSC risk was achieved at approximately 50 MET hours/week in a traditional dose-response analysis. Compared with those with minimal activity, consistently reaching the guideline at moderate levels (median, 16.9 MET hours/week) over three decades was associated with significant reductions in DSC risk (hazard ratio, 0.83), while no further benefit was seen with much higher amounts (median, 38.5 MET hours/week; hazard ratio, 0.87)."The fact that consistency is important allows someone to do something at lower levels over time, repeatedly," Christine Molmenti, Ph.D., M.P.H., associate professor and cancer epidemiologist at Northwell Health in New Hyde Park, New York, said in a statement.Abstract/Full Text (subscription or payment may be required).Sign up for our weekly HealthDay newsletter