Low heart rate variability and cancer-related fatigue in breast cancer survivors.
Cancer-related fatigue is a common and often long lasting symptom for many breast cancer survivors. Fatigued survivors show evidence of elevated inflammation, but the physiological mechanisms driving inflammatory activity have not been determined. Alterations in the autonomic nervous system, and particularly parasympathetic nervous system activity, are a plausible, yet understudied contributor to cancer-related fatigue. The goal of this study was to replicate one previous study showing an association between lower parasympathetic activity and higher fatigue in breast cancer survivors (Fagundes et al., 2011), and to examine whether inflammation mediates this association. Study participants were drawn from two samples and included 84 women originally diagnosed with early stage breast cancer prior to age 50. Participants completed questionnaires, provided blood samples for determination of interleukin (IL)-6 and C-reactive protein (CRP), and underwent electrocardiography (ECG) assessment for evaluation of resting heart rate variability (HRV), a measure of parasympathetic activity. Results showed that lower HRV was associated with higher fatigue (p<.05), as predicted. In bivariate analyses, HRV was also correlated with circulating concentrations of IL-6 and CRP. However, path analyses did not support inflammation as a mediator of the association between HRV and fatigue; instead, associations among these variables appeared to be driven by age and BMI. These findings identify HRV as a potential contributor to cancer-related fatigue, but suggest that inflammation does not mediate this association in younger, healthy breast cancer survivors who are several years post-treatment. The autonomic nervous system merits additional attention in research on the etiology of cancer-related fatigue.
UCLA Department of Psychology, 1285 Franz Hall, Box 951563, Los Angeles, CA 90095-1563, USA. Electronic address: ahdupont@ucla.edu.
Alexandra D
AD
Crosswell
University of Pittsburgh, Department of Psychology, 210 South Bouquet Street, Sennott Square 3rd Floor, Pittsburgh, PA 15260, USA.
Kimberly G
KG
Lockwood
UCLA Schools of Medicine & Public Health, 650 Charles Young Drive South, Room A2-125 CHS, Los Angeles, CA 90095-6900, USA; UCLA Jonsson Comprehensive Cancer Center, 650 Charles Young Drive South, Room A2-125 CHS, Los Angeles, CA 90095-6900, USA.
Patricia A
PA
Ganz
UCLA Department of Psychology, 1285 Franz Hall, Box 951563, Los Angeles, CA 90095-1563, USA; UCLA Jonsson Comprehensive Cancer Center, 650 Charles Young Drive South, Room A2-125 CHS, Los Angeles, CA 90095-6900, USA; UCLA Department of Psychiatry and Behavioral Sciences, 1285 Franz Hall, Box 951563, Los Angeles, CA 90095-1563, USA.
Julienne E
JE
Bower
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008875:Middle Aged; D001943:Breast Neoplasms / Q000097:blood / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology; D005221:Fatigue / Q000097:blood / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology; D018836:Inflammation Mediators / Q000097:blood; D019122:Meditation / Q000523:psychology; D064866:Mindfulness; D009043:Motor Activity; D017741:Survivors / Q000523:psychology / Q000706:statistics & numerical data; D064887:Observational Studies as Topic; D016032:Randomized Controlled Trials as Topic
D018836:Inflammation Mediators
Autonomic functioning; Autonomic nervous system; Inflammation; Parasympathetic activity; Symptoms