ASPO Abstracts
Prolonged, uninterrupted bouts of sedentary behavior are associated with fatigue in breast cancer survivors
Category: Lifestyles Behavior, Energy Balance & Chemoprevention, Survivorship & Health Outcomes/Comparative Effectiveness Research
Conference Year: 2018
Abstract Body:
Purpose: Sedentary behavior (SB) has been investigated as a factor in the development of several chronic diseases (e.g., obesity, diabetes). However, the relationship between SB and fatigue in cancer survivors has not been explored. This study examined associations between physical activity (PA), SB, and fatigue in breast cancer survivors. Methods: A subsample of breast cancer survivors who completed an 8-week PA intervention (N=7) wore an activPAL accelerometer for seven-consecutive days at post-intervention. activPAL variables of interest were step count, minutes of moderate to vigorous PA (MVPA), bouts of MVPA >10 minutes, minutes in SB, and prolonged, uninterrupted bouts of SB >30 and >60 minutes. The Functional Assessment of Chronic Illness Therapy (FACIT) Fatigue questionnaire measured fatigue, higher scores indicate less fatigue. Pearson correlations explored associations between post-intervention fatigue and activPAL variables. Hierarchical regression models to predict post-intervention fatigue included cancer stage, baseline fatigue and significant (p<.05) univariate predictors. Results: Fatigue improved from baseline to post-intervention [Mˆ†+10.43±10.74, t(6)=-3.76, p=.009]. Post-intervention fatigue was associated with bouts of SB >30 (r= -.876, p=.01) and >60 minutes (r=-.861, p=.01). No PA variables were associated with fatigue (p>.05). Cancer stage, baseline fatigue and SB >30 minutes predicted post intervention fatigue [F(3,6)=23.29, p=.014, R2=.96]. SB >30 minutes accounted for an additional 32.5% of the variance [B=-2.26, SE=.464, t(3)=-4.866, p=.017]. The regression analysis for sedentary bouts >60 minutes was not significant [F(3,6)=3.13, p=.187]. Conclusion: Reducing and/or interrupting prolonged sedentary time may improve fatigue in breast cancer survivors. These analyses found that eliminating 1.6 bouts of SB >30 minutes per day improved fatigue by 3.7 points on the FACIT, exceeding the minimal clinically important difference of 3. However, these large effects should be interpreted with caution due to the small sample size. In addition, SB and fatigue may have a bi-directional relationship, with higher levels of fatigue leading to more time in SB. Further research is needed to test how reductions in SB impact changes in fatigue.
Keywords: physical activity; sedentary behavior; fatigue; breast cancer