 The investigators will use the Hochberg procedure12 to control false discovery rates at 5. Analyses will be based on intent to treat with two-sided tests. The effect of HRV-B on coherence and other HRV variables will be analyzed using linear mixed models for repeated measures data from sequential time assessments, and a between-subjects factor to evaluate the intervention after adjusting for potential confounding factors e.g., age, standard therapy, medications, co-morbid disease. Baseline relationships between HRV and endpoints will be examined using multiple regression models. Few studies have examined the multivariate relationship between pain, autonomic dysfunction, stress, depression, sleep, restactivity rhythms, fatigue, and cognition. 