Breast Cancer Survivors (BCS) have clusters of related symptoms. One proposed treatment related symptom cluster includes fatigue, cognitive changes, depression, pain, and sleep disturbances. The continuation of this cluster and effects of exercise after treatment has not been thoroughly studied. Understanding how exercise impacts this symptom cluster will expand our knowledge of BCS and may lead to improved quality of life. Team triathlon training is a unique and effective type of exercise for this population. PURPOSE:To examine the effects of triathlon training on a treatment related symptom cluster in BCS to determine the relationships in the cluster. METHODS: Female BCS (n = 207) participated in one of 7 seasons of a 14-week sprint triathlon training program. Training consisted of 2 supervised and 3 unsupervised sessions per week. Baseline and Post- training measures over the years included fatigue (FACIT-F), and PROMIS questionnaires for cognition (Applied Cognition-General Concerns-Short Form), depression (Emotional Distress-Depression), pain (Pain Interference-SF), and sleep (Sleep Disturbance-SF). Except FACIT-F, higher questionnaire scores represent worse function. T-tests, including Cohen's d for effect sizes, were calculated on pre- and post-training data.RESULTS: Data are mean (SD). Fatigue, (pre= 38.9 (10.2), post= 46.5 (5.2), p< 0.01, d=-0.79), cognition (pre= 16.6 (7.8), post= 13.7 (6.4), p< 0.01, d= 0.42), depression, (pre= 12.0 (5.4.), post= 9.9 (3.7), p< 0.01, d=0.38), and pain (pre=11.2 (4.6), post= 10.0 (4.1), p< 0.05, d=0.30) presented such that is unlikely that these means are equal over time. In contrast, it is not unlikely for sleep that the mean is equal over time (pre= 14.5 (5), post= 13.8 (3.4), p=0.25, d=0.22). CONCLUSIONS: Triathlon training for BCS improved all symptoms in a cluster, we only failed to reject the null for the smallest effect size presented in sleep. The effect size was medium for fatigue and small for cognition, depression and pain. The symptoms in this cluster of fatigue, cognitive changes, depression, and pain all were present and improved, except sleep disturbances which did not improve in this group of post-treatment female cancer survivors.