Sleep & Recovery — Overview

Why Sleep is the Foundation of Health

Sleep is not downtime — it's active restoration. During sleep:

•Brain: Clears metabolic waste (amyloid beta), consolidates memories, processes emotions

•Body: Repairs tissue, synthesizes proteins, releases growth hormone

•Immune system: Produces cytokines, fights infection

•Heart: Blood pressure drops 10-20% (non-dippers have higher cardiovascular risk)

Impact of sleep deprivation (even 1 week of 6hr sleep):

•Cognitive performance equivalent to 24 hours without sleep

•Immune response drops by 30%

•Cortisol rises, testosterone falls

•Insulin sensitivity decreases (pre-diabetic glucose response)

How Much Sleep Do You Need?

Age Group	Recommended Sleep

|-----------|------------------|

Adults (18–64)	7–9 hours
Older adults (65+)	7–8 hours
Teenagers (14–17)	8–10 hours
School age (6–13)	9–11 hours

Quality matters as much as quantity. 8 hours of interrupted sleep ≠ 8 hours of continuous sleep.

Sleep Architecture — The 4 Stages

Stage 1 (N1): Light sleep, 5–10 min, easy to wake, hypnic jerks common
Stage 2 (N2): True sleep onset, 20 min, body temperature drops, heart slows
Stage 3 (N3): Deep sleep (slow-wave), 20–40 min, hardest to wake, physical restoration
REM:          Dream sleep, 20–25% of total sleep, memory consolidation, emotional processing

One sleep cycle = ~90 minutes. 5 cycles = 7.5 hours.
Deep sleep dominates early cycles; REM dominates later cycles.

Evidence-Based Sleep Hygiene

Environment (most impactful)

•Temperature: 65-68°F (18-20°C) is optimal for sleep onset

•Darkness: 0 lux during sleep. Blackout curtains or sleep mask.

•Noise: < 30 dB or use consistent white/pink noise

•Phone: Outside bedroom, or at minimum face-down, Do Not Disturb on

Timing (circadian entrainment)

•Consistent wake time: The most powerful circadian signal. Even weekends.

•Morning light: Get outside within 30 minutes of waking (no sunglasses). Sets cortisol peak.

•Evening light: Dim lights after sunset. Blue light from screens delays melatonin by 1.5–3 hours.

Behaviours

•Caffeine cutoff: 12–14 hours before bed (half-life = 5–7 hours; quarter-life = 10–14 hours)

- If you sleep at 11pm, last coffee should be 10–11am

•Alcohol: Disrupts REM sleep and causes fragmented sleep second half of night

•Exercise: Improves sleep quality, but intense exercise < 3 hours before bed can delay sleep

•Wind-down routine: 30–60 minutes of low stimulation before bed

Common Sleep Problems

Can't fall asleep (sleep onset insomnia)

•Racing thoughts → Try 4-7-8 breathing or body scan meditation

•Too warm → Drop room temperature

•Caffeine too late → Track intake timing

•Blue light → Use f.lux or Night Shift after sunset

Wake up in middle of night (sleep maintenance insomnia)

•Alcohol → Avoid after 7pm

•Bladder → Limit fluids 2 hours before bed

•Stress → Write tomorrow's tasks before bed ("offloading")

•Sleep apnea → Suspect if snoring, morning headaches, unrefreshed after sleep

Can't wake up (delayed sleep phase)

•Social jet lag (late weekends) → Fix wake time 7 days a week

•Insufficient morning light → Go outside immediately upon waking

•Too much evening light → Strict light discipline after 8pm

Tracking Sleep

•Oura Ring: Most accurate consumer device (HRV, sleep stages, temperature)

•Apple Watch / Fitbit: Good for trends, less accurate on stages

•Free: Just track bedtime, wake time, and subjective morning freshness (1–10 scale)

Key metric to track: HRV (Heart Rate Variability) — higher = better recovered, lower = stressed/ill/overtraining

Sleep & Morning Routine — Overview