A new study shows that respiratory sinus arrhythmia (RSA) is a significant predictor of insomnia in women with breast cancer and confirmed that longer nocturnal wake episodes were associated with a flatter diurnal cortisol slope.
Results of this study confirmed a relationship between frequent awakenings and abnormal cortisol (a steroid hormone that regulates blood pressure), rhythms in metastatic breast cancer, thus concluding that a disrupted cortisol rhythm may have serious medical implications in women with breast cancer.
With the addition of demographics, disease severity and psychological variables, findings suggest that Vagal regulation, assessed via RSA, an important marker of parasympathetic tone, is the most consistent and significant predictor of sleep continuity disturbance.
Diminished RSA has been associated with both worse medical and psychiatric health. Previous studies suggest that RSA is associated and may even be predictive for insomnia in healthy subjects.
“It was surprising to see that the strongest association was between a parasympathetic nervous system dysregulation and sleep problems even after we considered patients’ age, their disease severity, type of treatment and psychological variables such as pain and stress,” said the study’s lead author, Oxana Palesh, PhD, Research Assistant Professor at the University of Rochester Cancer Center.
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