Abstract—Sleep onset latency (SOL) is an objective indicator of sleepiness and is being used clinically as a diagnostic tool for sleep deprivation.Thisstudyproposesanewandlessintrusiveapproach toestimateSOLbasedonthebloodpressure(BP)regulatoryreflex mechanism.Wehypothesizedthatthearterialbaroreflex,onekind of reflex mechanism for BP regulation, maintains the toning-down effect sleep has on…