Robust efficiency and actuator saturation explain healthy heart rate control and variability.

The correlation of healthy states with heart rate variability (HRV) using time series analyses is well documented. Whereas these studies note the accepted proximal role of autonomic nervous system balance in HRV patterns, the responsible deeper physiological, clinically relevant mechanisms have not been fully explained. Using mathematical tools from control theory, we combine mechanistic models of basic physiology with experimental exercise data from healthy human subjects to explain causal relationships among states of stress vs. health, HR control, and HRV, and more importantly, the physiologic requirements and constraints underlying these relationships. Nonlinear dynamics play an important explanatory role--most fundamentally in the actuator saturations arising from unavoidable tradeoffs in robust homeostasis and metabolic efficiency. These results are grounded in domain-specific mechanisms, tradeoffs, and constraints, but they also illustrate important, universal properties of complex systems. We show that the study of complex biological phenomena like HRV requires a framework which facilitates inclusion of diverse domain specifics (e.g., due to physiology, evolution, and measurement technology) in addition to general theories of efficiency, robustness, feedback, dynamics, and supporting mathematical tools.

Resident education and perceptions of recovery in serious mental illness: observations and commentary.

OBJECTIVE: Recovery is emerging as a guiding influence in mental health service delivery and transformation. As a consequence, the expectations and curricular needs of trainees (as future stakeholders in a transformed, recovery-oriented system) are now of considerable importance. METHOD: To this end, resident-led focus groups were held at the Medical College of Georgia to obtain perceptions of the Recovery Model. Certified Peer Support Specialists (CPSS) attended and topics covered were the Recovery Model, the CPSS training curriculum, and developing a Wellness Recovery Action Plan (WRAP) with consumers. RESULTS: Advantages and disadvantages of the Recovery model were discussed, with residents generally expressing cautious optimism regarding implementation of these principles, yet concern regarding the potential for diminishing confidence and support for traditional professional services. All residents indicated an interest in obtaining more information about the Recovery Model, including how to incorporate WRAPS and the role of CPSS in Recovery. Almost half of the residents selected a recovery-oriented workshop as the best method for further education about these concepts, with less support for other options of didactic handouts and expert lecture. CONCLUSIONS: Future efforts should be directed at implementing recovery curricula into resident education and evaluating the changes in resident knowledge, attitude toward recovery, and plans to implement recovery-oriented principles into their own professional practice.