The Best Exercise Modality and Dose to Reduce Cancer-Related Fatigue in Breast Cancer: A Systematic Review with Network and Dose–Response Meta-Analyses

Objectives This study investigates the dose-response relationship between various exercise modalities and cancer related fatigue (CRF) in breast cancer patients, aiming to establish evidence-based, tailored exercise prescriptions for clinical guidance.Methods Exercise dose was calculated as the product of duration, frequency, and intensity, expressed in metabolic equivalents of task minutes per week (MET-min/week), for comparison across studies. Bayesian network and dose-response meta-analyses using a random-effects model were conducted to evaluate the impact of exercise on fatigue.Results Eighty seven studies with 6,916 patients were included. An inverted U-shaped dose-response was observed between exercise and CRF, with an effective dose range being 0 to 1200 MET-min/week, peaking at 720 MET-min/week (SMD = 1.01, 95% Credible Interval [CrI]: 0.72, 1.34). Subgroup analysis showed that for cancer survivors who have completed primary treatments, the peak effect occurs at 690 MET-min/week (SMD = 1.24, 95% CrI: 0.69, 1.81), whereas for patients undergoing primary treatment, the peak effect is observed at 780 MET-min/week (SMD = 0.92, 95% CrI: 0.6, 1.29). When stratified by exercise modality, aerobic exercise (0-120 min/week), resistance training (140-270 min/week), combined aerobic and resistance training (0-240 min/week), and yoga (0-340 min/week) were all significantly associated with fatigue reduction. The ranking suggested that 75 minutes of aerobic exercise per week (SMD = 1.28, 95% CrI: 0.7, 1.86) may be optimal.Conclusions Aerobic exercise, resistance training, combined aerobic and resistance training, and yoga significantly improved CRF in breast cancer population, with moderate-to-vigorous aerobic exercise at approximately 75 min/week showing the greatest potential benefit. These findings may inform evidence-based exercise prescriptions and optimize CRF management in breast cancer population.