Simultaneous recordings of beat-by-beat values of HR (by ECG of Thoracic Electrical Bioimpedance System), SI (by TEB System) and MAP (by FinaPress) over a 10-minute period in a reclining, resting adult male. Courtesy David Shannahoff-Khalsa, The Research Group for Mind-Body Dynamics, Institute for Non-linear Science, University of California San Diego, California