Technology & Sleep
Screens, trackers, shift work, and jet lag — how modern life disrupts sleep and what to do about it
Modern technology creates both problems and solutions for sleep. Screens disrupt circadian rhythms, but trackers can reveal patterns. Shift work is devastating for health, but strategic light exposure can help. Here's what actually matters.
Screens & Blue Light
The conventional wisdom is that blue light from screens ruins sleep. The reality is more nuanced — blue light matters, but mental stimulation and time displacement may matter more.
📱 The Real Problems
- Mental stimulation: Engaging content activates the brain when it should be winding down
- Time displacement: "One more episode" pushes back bedtime
- Blue light: Suppresses melatonin by 50%+ at night, but this is a smaller effect than stimulation
- Emotional activation: News, social media, work email create arousal
✅ What Actually Helps
- Screen curfew: 30-60 minutes before bed (most important)
- Night mode: Reduces blue light exposure by ~50%
- Dimming: Lower brightness in evening hours
- Content choice: Boring > stimulating if you must use screens
- Blue-blocking glasses: Modest help, not magic
Sleep Trackers: What They Can (and Can't) Tell You
Consumer sleep trackers have exploded in popularity. They're useful for identifying patterns, but their accuracy has limits — especially for sleep stage classification.
| Metric | Accuracy | Notes |
|---|---|---|
| Sleep vs. Wake | ~90% | Reliable for total sleep time estimates |
| Sleep Onset | ~85% | Good at detecting when you fall asleep |
| Light Sleep (N1/N2) | ~70% | Often overestimated; treat as approximate |
| Deep Sleep (N3) | ~65% | Frequently misclassified; use for trends only |
| REM Sleep | ~60% | Least accurate; don't obsess over numbers |
| Sleep Quality Score | Variable | Proprietary algorithms; limited validation |
✅ Good Uses for Trackers
- Identifying bedtime and wake time patterns
- Tracking consistency over weeks/months
- Spotting correlations (alcohol, exercise, etc.)
- Motivating behavior change
❌ Don't Rely on Trackers For
- Precise sleep stage percentages
- Diagnosing sleep disorders
- Daily optimization decisions
- Replacing how you actually feel
Shift Work
Approximately 20 million Americans work night shifts or rotating schedules. The health consequences are significant — shift work is classified as a probable carcinogen by the WHO due to circadian disruption.
🛡️ Harm Reduction Strategies
- Bright light during shift: Helps shift circadian rhythm
- Sunglasses on commute home: Blocks morning light
- Blackout bedroom: Essential for daytime sleep
- Consistent schedule when possible: Permanent nights may be less harmful than rotating
- Strategic napping: Before or during shift can help
⚠️ What to Monitor
- Metabolic markers (blood glucose, weight)
- Cardiovascular risk factors
- Mental health symptoms
- Drowsy driving risk
- Total weekly sleep hours
Jet Lag
Jet lag results from desynchronization between your internal clock and local time. Eastward travel is generally harder than westward because your natural rhythm is slightly longer than 24 hours.
✈️ Eastward Travel (Harder)
- Requires advancing your clock (going to bed earlier)
- Get bright light in the morning at destination
- Avoid light in evening before travel
- Consider low-dose melatonin in evening
- Recovery: ~1 day per timezone crossed
✈️ Westward Travel (Easier)
- Requires delaying your clock (staying up later)
- Get bright light in the evening at destination
- Avoid morning light initially
- Melatonin less necessary
- Recovery: ~0.7 days per timezone crossed