Sleep stages and why they matter
Across a healthy night the body cycles 4–6 times, ~90 minutes each. Every cycle contains:
- NREM 1–2 — light sleep, transition phase
- NREM 3 (deep sleep) — physical recovery, growth hormone, immunity, glymphatic clearance of the brain
- REM — dreaming, emotional processing, memory consolidation, creativity
Deep sleep dominates the first half of the night, REM the second. Evening alcohol, caffeine after midday and an irregular bedtime break that architecture.
Morning protocol
- Wake at the same time every day (±30 min), weekends included — calibrates the circadian clock
- Daylight in the eyes for 15 minutes within the first hour (outdoors, not through a window)
- Breakfast within 1–2 hours of waking (or skip if you fast)
- No coffee for the first 90 minutes after waking (so adenosine clears naturally)
Daytime protocol
- Movement: 30 min of moderate activity a day raises deep sleep by 20–30%
- Caffeine stop at midday — half of a 4 p.m. coffee is still affecting sleep that night
- Lunch 12–13, dinner 18–19 — last meal at least 3 h before bed
- Naps: if needed, max 20 min and before 3 p.m.
Evening protocol (starts 3 h before bed)
3 h before — last meal
Protein and vegetables; avoid heavy carbs and alcohol. Alcohol helps you fall asleep but destroys REM.
2 h before — dim the lights
Reduce bright light — prefer warm yellow under 2700K. Blue light suppresses melatonin.
1 h before — screens off
Phone, TV, computer off. Book, conversation, gentle stretching. If a screen is unavoidable, use blue-light blockers.
30 min before — cool the body
A warm shower or bath — the body cools faster after being warmed, which is the falling-asleep signal. Bedroom 17–19°C.
Sleep
Completely dark room, silence (or pink noise), phone in another room or on airplane mode.
Measurable targets (smartwatch)
| Marker | Good | Optimal |
|---|---|---|
| Sleep duration | 7 h | 7.5–8.5 h |
| Deep sleep | 1.0–1.5 h | 1.5–2 h |
| REM sleep | 1.0–1.5 h | 1.5–2 h |
| HRV (nightly average) | 30–50 ms | 50–80 ms |
| Resting heart rate | 60–70 | 50–60 |
Sleep duration
- Good
- 7 h
- Optimal
- 7.5–8.5 h
Deep sleep
- Good
- 1.0–1.5 h
- Optimal
- 1.5–2 h
REM sleep
- Good
- 1.0–1.5 h
- Optimal
- 1.5–2 h
HRV (nightly average)
- Good
- 30–50 ms
- Optimal
- 50–80 ms
Resting heart rate
- Good
- 60–70
- Optimal
- 50–60
If sleep problems persist after 4 weeks of consistent protocol, book a consultation — there may be hidden sleep apnoea or a hormonal cause: info@synage.ee