Korman Center, Room 245, 15 South 33rd Street, Philadelphia, PA 19104
Colloquium: Why Breathing Deep and Slow is Good for You - Insights from Respiratory Sinus Arrhythmia
Wednesday, April 23, 2014
3:00 PM-4:00 PM
Alona Ben-Tal, PhD, senior lecturer, Massey University
Respiratory sinus arrhythmia (RSA) is a heart rate variability at the frequency of breathing. It is widely accepted that the loss of RSA is a prognostic indicator for cardiovascular disease and that the prominent presence of RSA indicates a healthy cardiac system, yet the reasons for this are still being debated. We have shown using a variety of mathematical techniques and mathematical models that RSA may serve to minimize the energy expenditure of the heart while keeping arterial carbon dioxide levels at physiological tensions; our theoretical study did not support a previously suggested hypothesis that the physiological function of RSA is to match ventilation and perfusion in the lungs and thus optimize oxygen uptake and carbon dioxide removal. The models range from a 2D simplified model of gas exchange in which the optimal heart rate can be calculated directly, to a model that takes into account variation in heart rate due to changes in blood pressure, lung volume and neural respiratory drive and can mimic a range of experimental observations including key features of RSA. The models as well as other new insights they provided will be described. The work was done in collaboration with Sophie S. Shamailov (Massey University) and Julian F.R. Paton (University of Bristol) and was partly supported by NIH Grant R01 NS069220.