Evidence Hub

Biobehavioral factors mediate exercise effects on fatigue in breast cancer survivors

Rogers LQ, Vicari S, Trammell R, Hopkins-Price P, Fogleman A, Spenner A, Rao K, Courneya KS et al.

Medicine and science in sports and exercise, 2014

46 participants · 70 citations

Abstract

Purpose: This study aimed to examine mediators of fatigue response to an exercise intervention for breast cancer survivors in a pilot randomized controlled trial.

Methods: Postmenopausal breast cancer survivors (n = 46; ≤stage 2), off primary treatment, and reporting fatigue and/or sleep dysfunction were randomized to a 3-month exercise intervention (160 min·wk of moderate-intensity aerobic walking, twice weekly resistance training with resistance bands) or control group. Six discussion group sessions provided behavioral support to improve adherence. Fatigue, serum cytokines, accelerometer physical activity, cardiorespiratory fitness, sleep dysfunction, and psychosocial factors were assessed at baseline and 3 months.

Results: The exercise intervention effect sizes for fatigue were as follows: fatigue intensity d = 0.30 (P = 0.34), interference d = -0.38 (P = 0.22), and general fatigue d = -0.49 (P = 0.13). Using the Freedman-Schatzkin difference-in-coefficients tests, increase in fatigue intensity was significantly mediated by interleukin 6 (IL-6) (82%), IL-10 (94%), IL-6/IL-10 (49%), and tumor necrosis factor-α (TNF-α):IL-10 (78%) with reduced sleep dysfunction increasing the relationship between intervention and fatigue intensity rather than mediating intervention effects (-88%). Decrease in fatigue interference was mediated by sleep dysfunction (35%), whereas IL-10 and pro-anti-inflammatory cytokine ratios increased the relationship between intervention and interference…

How strong is the evidence?

Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 46 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

Read the paper

Related studies

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free