Biological Sleep Need (Homeostatic Quota)Duration in Decimal Hours (AASM & NSF Gold Standard)
The genetically and developmentally determined nightly sleep duration required to maintain optimal neurocognitive, metabolic, and immunological function without daytime somnolence. Governed by the Two-Process Model of Sleep Regulation (Borbely, 1982), where Process S homeostatic sleep pressure (adenosine accumulation) balances with Process C circadian wake drive. Clinical guidelines from the American Academy of Sleep Medicine (AASM) establish 7.0 to 9.0 hours for adults (18-64), 7.5 to 9.5 hours for young adults, and 8.5 to 10.0 hours for high-performance athletes.
Default: 8.0 Hours (Adult Baseline)
Actual Total Sleep Time (TST)Effective Restorative Duration in Hours
The exact physiological duration spent in non-rapid eye movement (NREM Stages N1, N2, N3 Slow-Wave Sleep) and rapid eye movement (REM) sleep, distinct from total Time in Bed (TIB). TST excludes sleep onset latency (time to fall asleep, typically 10-20 minutes) and wake after sleep onset (WASO nocturnal awakenings). Only actual TST clears adenosine from the basal forebrain and allows glymphatic brain waste clearance.
Default: 6.5 Hours (Typical Deficit Input)
Sleep Efficiency Index (SEI)Percentage Ratio (TST / TIB x 100%)
The proportion of time spent in bed that is actually spent sleeping. A clinical gold standard SEI is 85% or greater; values below 80% indicate significant sleep fragmentation, insomnia, or environmental sleep disturbance. When SEI falls below 85%, nominal bed time severely overestimates restorative sleep, causing unmeasured, compounding sleep debt.
Default: 88.0% (Normal Clinical Benchmark)
Cumulative Sleep Debt BalanceRunning Delta Balance in Hours (Negative Hours Deficit)
The cumulative mathematical deficit accrued over a rolling 7-to-14 day window, calculated as the sum of nightly deficits: Sum(Biological Need - Actual TST). Clinical thresholds define debt severity: Nominal (0 to 2 hrs), Mild (2 to 5 hrs, modest daytime drowsiness), Moderate (5 to 10 hrs, measurable executive function decline), Severe (10 to 15 hrs, vigilance lapses matching BAC 0.05%), and Chronic Sleep Deprivation (>15 hrs, severe neurobehavioral impairment and metabolic dysregulation).
Default: -6.5 Hours (Subclinical Moderate Deficit)
Catch-Up Repayment VelocityIncremental Sleep Extension Rate (Minutes per Night)
The clinically safe nightly sleep extension increment applied to repay accumulated debt without disrupting the central circadian pacemaker (suprachiasmatic nucleus). Research from sleep physiology demonstrates that extending sleep by 30 to 60 minutes per night—combined with 20-minute afternoon power naps—efficiently clears debt across 7 to 10 days while preventing sleep drunkenness (sleep inertia) and circadian phase delay.
Default: +45 Minutes / Night (Safe Repayment Pace)
Social Jetlag (Delta Midpoint of Sleep)Chronobiological Discrepancy in Hours / Minutes
The absolute time difference between the midpoint of sleep on workdays (MSW) and the midpoint of sleep on free weekend days (MSFsc = Sleep Start + 0.5 x Sleep Duration). A social jetlag exceeding 1.0 hour indicates substantial circadian misalignment, which elevates cardiometabolic risk, promotes Sunday night insomnia, and impairs Monday cognitive performance regardless of total hours slept.
Default: 1 Hour 15 Minutes (Moderate Social Jetlag)
