Rogers, L.Q., Vicari, S., Trammell, R., Hopkins-Price, P., Fogleman, A., Spenner, A., . . . Verhulst, S. (2013). Biobehavioral factors mediate exercise effects on fatigue in breast cancer survivors. Medicine and Science in Sports and Exercise, 46, 1077-1088.

DOI Link

Study Purpose

To examine mediators of fatigue effects of an exercise intervention

Intervention Characteristics/Basic Study Process

Patients were randomized to an exercise intervention or control group. The intervention combined walking and strength training with resistance bands. Walking was gradually increased by week 9 to 40 minute sessions of moderate intensity, four times per week, and participants attended 26 individual exercise sessions supervised by an exercise specialist. Resistance training was two times per week in the last 10 weeks of the study with the supervised aerobic walking sessions. Resistance was advanced as tolerated. Six group meetings with a psychologist also were provided every other week to provide support and improve exercise adherence. The control group was instructed to maintain usual exercise behavior.

Sample Characteristics

  • N = 42  
  • MEAN AGE = 56.2 years (SD = 7.7)
  • KEY DISEASE CHARACTERISTICS: All patients had breast cancer, were at least four weeks post-completion of primary treatment, had an average fatigue score of at least 3 in the past week, or had sleep dysfunction
  • OTHER KEY SAMPLE CHARACTERISTICS: Multiple chronic concurrent conditions were excluded

Study Design

  • RCT

Measurement Instruments/Methods

  • MTI actigraph
  • Fatigue Symptom Inventory
  • PROMIS general fatigue scale
  • PROMIS scales for depression, anxiety, and sleep/wake disturbance
  • Serum samples for interleukins (IL-6, -8, -10) and tumor necrosis factor alpha


Adherence to supervised exercise sessions was 91%–93%. Exercise goals for at home were met in 65% of the weeks during the study. General fatigue declined significantly in the intervention group compared to controls (d = –0.49, p < .01). Fatigue interference (d = –0.38, NS) declined in the intervention group. Fatigue intensity increased in the intervention group and declined in controls (d = 0.3, NS). There were no significant differences in depression. Anxiety declined in the intervention group (d = –0.54, p < .05). Sleep/wake dysfunction declined in both groups over time, but more in the intervention group (d = –0.054, p < .01). Positive effects in fatigue intensity were significantly mediated by IL-6, IL-10, IL-6:IL-10, and TNF alpha:IL-10.


The exercise program used here showed a small to medium non-significant effect on fatigue intensity and interference, as measured in this study. Effects of exercise on fatigue were mediated by some cytokine system responses.


  • Small sample (< 30)
  • Baseline sample/group differences of import
  • Risk of bias (no blinding)
  • Risk of bias (no appropriate attentional control condition)
  • Other limitations/explanation: Fatigue and sleep disruption measures at baseline were lower in the intervention group, although the difference was not statistically significant, these could have influenced the general trends shown in the study.

Nursing Implications

Although this study has limitations, findings do provide additional support for positive effects of exercise on cancer-related fatigue among cancer survivors. Findings here show evidence of potential effects through the cytokine system. Adherence to the exercise program in this study was very good, using a support group interaction and the combination of supervised exercise sessions and home-based exercise recommendations. This type of additional support may help many patients adhere to an exercise program.