“…More precisely, this practice, executed in supine position, naturally stimulates a hypnagogic state wherein an individual is physiologically asleep yet maintains an internal/external awareness (Sharpe et al, 2021); there is a withdraw from other senses, and only the auditory channel is open so that the participant stays aware of the directions coming from the instructor, but practices detachment from all other stimuli. YN interventions have been associated with significant improvements in sleep parameters such as sleep onset latency and sleep quality (Datta et al, 2017;Moszeik et al, 2020) because of a general parasympathetic dominance (Markil et al, 2012) and a subsequent high cardiac vagal control (Werner et al, 2015; see also YN Effects and Potential Benefits on Athletes); it first stimulates the parasympathetic nervous system increasing heart rate variability (HRV), or its high-frequency components (Markil et al, 2012), and alpha waves, to then demonstrate the symptoms of deep, non-REM sleep, including theta and delta brain waves (Parker et al, 2013).…”