Sleep Hygiene: The Evidence-Based Guide to Better Sleep Every Night

Sleep hygiene isn't about dimming your phone before bed — it's about systematically aligning your environment and behaviours with your circadian biology. These are the interventions with the strongest clinical evidence for improving sleep quality in people who struggle to fall or stay asleep.

The Foundation: Circadian Rhythm Anchoring

Your circadian clock is set by two primary inputs: light and timing. Getting these right is more powerful than any supplement.

Morning Light: The Most Important Sleep Habit

10-30 minutes of outdoor light within 60 minutes of waking anchors your circadian clock and sets the timer for melatonin production 14-16 hours later. This single habit improves both sleep onset and sleep quality more reliably than most pharmaceutical interventions. On cloudy days, the light intensity outdoors (1,000-10,000 lux) still significantly exceeds indoor lighting (50-500 lux) — go outside regardless of cloud cover.

Consistent Wake Time: The Non-Negotiable

Waking at the same time every day — including weekends — is the single most evidence-based sleep intervention. Irregular wake times disrupt circadian timing and reduce sleep drive accumulation. If you must vary your schedule, allow no more than 60 minutes of variation. Consistent wake time matters more than consistent bedtime.

Light Management in the Evening

Blue light: Screens emit blue light (wavelength 430-490nm) that directly suppresses melatonin by up to 80% within 2 hours of bedtime. Options: blue light blocking glasses (worn 2+ hours before bed), enabling Night Mode/warm display settings on all devices, or simply reducing screen time after 8pm. The glasses have the most consistent evidence for maintaining melatonin levels.

Dim all lights: Bright overhead lighting also suppresses melatonin — switch to lamps and lower-intensity lighting after 9pm. Even 100 lux can delay melatonin onset by 90 minutes in sensitive individuals.

Temperature: The Overlooked Lever

Core body temperature must drop 1-2°C to initiate and maintain deep sleep. Optimal bedroom temperature: 65-68°F (18-20°C). Warmer rooms reduce slow-wave sleep time measurably. Hot bath or shower 60-90 minutes before bed paradoxically improves sleep by triggering vasodilation — heat dissipates from the skin surface, accelerating core temperature drop on return to the cool bedroom.

Sleep Drive: Building the Pressure

Sleep drive (adenosine accumulation) builds throughout wakefulness and dissipates during sleep. Two mistakes destroy sleep drive: napping after 3pm (dissipates evening sleep pressure) and spending excessive time in bed awake (trains the brain to associate bed with wakefulness). If you can't fall asleep in 20 minutes, get up and do something calm until sleepy — this is Stimulus Control Therapy, the most evidence-based non-drug insomnia treatment.

The Evidence-Based Sleep Stack

For people doing all the above correctly but still struggling:

• Magnesium glycinate: 300-400mg elemental, 30-60 minutes before bed. Reduces sleep onset time, improves sleep quality via GABA support.
• L-theanine: 200-400mg before bed. Promotes relaxed alpha wave state conducive to sleep onset.
• Passionflower: 2-3g tea or 300-500mg extract, 30-60 minutes before bed. GABA-A modulation, clinical evidence for sleep onset improvement.
• Ashwagandha: 300mg with dinner (not at bed — too stimulating for some). Reduces cortisol over weeks, improving sleep quality long-term.

The magnesium + L-theanine baseline covers most people. Add passionflower if sleep onset remains slow. Add ashwagandha if stress and wired-tired feeling are prominent features.

What Doesn't Work (Despite Popularity)

Alcohol: Promotes sleep onset but fragments sleep architecture — dramatically reduces REM sleep, worsens sleep quality in the second half of the night.

High-dose melatonin (5-10mg): More isn't better. 0.5-1mg is the physiologically appropriate dose. High doses cause next-day grogginess, suppress natural melatonin production over time.

Sleeping in on weekends: "Social jet lag" — the circadian disruption from variable wake times causes more harm than the extra sleep provides benefit.