Restorative yoga postures that make use of forward bends are believed to activate parasympathetic nervous system (PNS) activity and to provide some relief. (yogauonline.com)
It is reported using several different metrics: high frequency (HF - HRV), a measure of parasympathetic nervous system activity, low frequency (LF - HRV), a measure of sympathetic nervous system activation, and LF: HF ratio, a measure of parasympathetic and sympathetic nervous system balance. (yogauonline.com)
Mindful entrainment of sympathetic and parasympathetic nervous system with HeartMath techniques (saragottfriedmd.com)