Sleep Optimization

What it is

Sleep is divided into REM and non-REM stages; deep (N3) non-REM dominates the first part of the night, REM the second. Both are essential. Sleep duration, regularity, and circadian alignment all influence health outcomes independently.

Why it matters

Habitual short sleep (<6 h) and very long sleep (>9 h) both associate with elevated cardiovascular, metabolic, and all-cause mortality. Sleep fragmentation predicts cognitive decline and dementia risk. Glymphatic clearance of brain interstitial waste, including amyloid-β, is markedly higher during deep sleep.

Mechanisms

• Glymphatic clearance of metabolic waste from the CNS.
• Memory consolidation in REM and non-REM.
• Metabolic regulation — even one night of restriction worsens insulin sensitivity.
• Immune function — vaccination response and viral susceptibility track with sleep.
• Cardiovascular — short sleep raises blood pressure and atherogenic risk.

Practical levers

• Regular timing (consistent sleep and wake times) is one of the highest-leverage variables.
• Morning bright-light exposure anchors the circadian rhythm.
• Avoid alcohol close to bedtime — suppresses REM, increases fragmentation.
• Cool, dark, quiet sleep environment.
• Screen for sleep apnoea in habitual snorers and anyone with excessive daytime sleepiness; untreated OSA is a major modifiable cardiovascular risk.

Safety

Sleeping medications — benzodiazepines, “Z-drugs” (zolpidem, zopiclone) — have meaningful side-effect profiles in older adults including falls and cognitive impairment. Cognitive behavioural therapy for insomnia (CBT-I) is first-line for chronic insomnia.

Related entries

See also: Chronic inflammation, Altered intercellular communication.