Sleep Optimization & Circadian Biology

Circadian rhythm is the 24-hour biological clock governing sleep, hormones, and metabolism. Understand its mechanism and how to optimise your clock.

Deep sleep (NREM N3) drives memory consolidation, glymphatic clearance, and growth hormone release. What it is, why it declines, and how to protect it.

Blue light (460-480 nm) suppresses melatonin via melanopsin retinal cells, delaying sleep onset by up to 1.5 hours and reducing REM sleep quality.

The glymphatic system flushes amyloid beta and tau from the brain during sleep. Impaired clearance from poor sleep is linked to Alzheimer’s disease risk.

Lux is the SI unit of illuminance. Covers the 100 lux melatonin threshold, melanopsin photoreception, and why dim screen light still disrupts sleep.

Melatonin is the body’s darkness signal, not a sedative. Learn how it works, the correct dosage, and why most OTC supplements are mislabelled.

The pineal gland is a pea-sized endocrine structure that secretes melatonin nocturnally to signal sleep onset and synchronise the body’s circadian clock.

Sleep debt is the cumulative gap between your sleep need and what you get. Learn why weekend catch-up cannot fully reverse the neurobehavioural deficit.

Social jet lag is the chronic mismatch between the internal clock and work schedules. Learn its metabolic cost, how to measure it, and how to reduce it.

Sleep onset latency is the time from lights-out to falling asleep. Healthy adults take 10-20 minutes; under 8 minutes signals pathological sleepiness.