Inflammation and psychosocial factors mediate exercise effects on sleep quality in breast cancer survivors: pilot randomized controlled trial

Abstract

Objective To improve mechanistic understanding, this pilot randomized controlled trial examined mediators of an exercise intervention effects on sleep in breast cancer survivors (BCS). Methods Forty-six postmenopausal BCS (≤ Stage II, off primary treatment) were randomized to a 3-month exercise intervention or control group. Intervention included 160 minutes/week of moderate intensity aerobic walking, twice weekly resistance training (resistance bands), and six discussion groups (to improve adherence). Blinded assessments at baseline and post-intervention included sleep disturbance (PSQI and PROMIS®), objective sleep quality (accelerometer), serum cytokines, accelerometer physical activity, cardiorespiratory fitness, body composition, fatigue, and psychosocial factors. Mediation was tested using Freedman-Schatzkin difference-in-coefficients tests. Results When compared with control, the intervention group demonstrated a significant increase in PSQI sleep duration (i.e., fewer hours of sleep/night) (d=0.73, p=.03). Medium to large but non-significant standardized effect sizes were noted for PSQI daytime somnolence (d=-0.63, p=.05) and accelerometer latency (d=-0.49, p=.14). No statistically significant mediators were detected for PSQI sleep duration score or accelerometer latency. Daytime somnolence was mediated by tumor necrosis factor (TNF)-alpha (mediated 23% of intervention effect, p<.05), interleukin (IL)-6: IL-10 (16%, p<.01), IL-8:IL-10 (26%, p<.01), and fatigue (38%, p<.05). Mediating or enhancing relationships for several of the sleep outcomes were noted for accelerometer physical activity, PROMIS® fatigue, exercise social support, and/or physical activity enjoyment. Conclusions Inflammation and psychosocial factors may mediate or enhance sleep response to our exercise intervention. Further study is warranted to confirm our results and translate our findings into more effective interventions aimed at improving sleep quality in BCS.

Sleep Quality in Women with Breast Cancer: An Integrative Review

“…In another study, when compared with controls, the intervention group demonstrated a significant increase in sleep duration with MBSR [18].…”

“…tance of longitudinal studies because analyzing the patient in 2 or more stages of treatment and documenting the difference in quality of sleep, may be helpful to nurses in managing their patients care. Nine articles reported randomized clinical trials [8,10,[16][17][18][19][20][21]] and 3 were a secondary analysis [4,[22][23].…”

“…In the studies selected for this review, the most common instrument used for data collection was the Pittsburgh Sleep Quality Index (PSQI) in 9 studies [2-4, 6, 9, 10, 14-17, 19-22, 24, 25], followed by actigraphy in 7 studies [6,17,18,22,[25][26][27] , sleep diaries in 6 studies [6,17,18,22,[25][26][27] and general questions in 1 study [15].…”

Physical Activity and Sleep Quality in Breast Cancer Survivors

“…The inability of this meta-analysis to detect sleep quality benefits is not unexpected given that currently published randomized controlled trials (RCTs) of aerobic exercise (e.g., home-based walking, supervised aerobic exercise) in breast cancer survivors specifically have not consistently reported beneficial intervention effects on sleep (10,22,27,30–32,34,37). In the seven trials measuring self-report, significant intervention effects were reported for overall sleep quality in four studies (two occurred during chemotherapy/radiation) (10,22,27,37), efficiency in one study (during chemotherapy) (10), latency in two studies (one during chemotherapy) (10,31), and sleep duration in one (post-chemotherapy/radiation) (30).…”

“…In the seven trials measuring self-report, significant intervention effects were reported for overall sleep quality in four studies (two occurred during chemotherapy/radiation) (10,22,27,37), efficiency in one study (during chemotherapy) (10), latency in two studies (one during chemotherapy) (10,31), and sleep duration in one (post-chemotherapy/radiation) (30). Another post chemotherapy/radiation trial reported beneficial effects on accelerometer measured efficiency, latency, and awake time (34).…”