SLEEP LOG // ARCHIVE
Field Notes from
the Sleep Lab
Logged records on on-device sleep tracking, phone-sensor sleep science, and building AI that never phones home. Every entry is processed locally — just like the app.
FEATURED RECORD // SPEC.001
On-Device AI Sleep Coaching: How It Works Without the Cloud
Can an AI sleep coach really run entirely on your phone? Here is how on-device AI analyzes your sleep patterns and gives guidance without sending anything to the cloud.
ARCHIVE // 21 RECORDS
SPEC.002
What Is Chronotype? Morning Lark vs Night Owl Explained
Your chronotype is your body's natural sleep timing. Learn whether you're a morning lark or night owl, and how to work with your pattern for better sleep.
SPEC.003
How to Fix a Broken Sleep Schedule (Jet Lag and Shift Work)
Willpower won't fix a broken sleep schedule. Here's how jet lag, shift work, and drifted bedtimes throw off your rhythm, and a realistic plan to reset it.
SPEC.004
Sleep Consistency vs Sleep Duration: Which Matters More?
Is sleeping 8 hours at random times better than 7 hours on a steady schedule? Here's how sleep consistency and duration work together, and why regularity wins.
SPEC.005
How Naps Affect Your Nighttime Sleep: What Science Says
Do naps wreck your nighttime sleep? It depends on how long you nap and when. Here's what the science says about nap timing, duration, and sleep pressure.
SPEC.006
Blue Light and Sleep: What the Research Actually Says (2026)
Does blue light from phones really ruin your sleep? We dig into the actual research on blue light, melatonin, and circadian rhythm — and what actually matters more.
SPEC.007
What Is Sleep Efficiency? How to Improve Yours in 2026
Sleep efficiency measures the share of your time in bed actually spent asleep. Learn what the number means, what a healthy range looks like, and how to improve yours.
SPEC.008
How Accurate Is Phone-Based Sleep Tracking in 2026?
Can your phone really measure your sleep? Here is what phone-based sleep tracking gets right, where it falls short, and how to get the most accurate results.
SPEC.009
Do Sleep Trackers Drain Battery Overnight? Explained
Worried sleep tracking will kill your phone battery? Here is how much battery sleep trackers actually use, what drains it most, and how to keep usage low.
SPEC.010
The Best Time to Sleep, According to Sleep Science
There is no single perfect bedtime. Sleep science shows consistent timing aligned with your circadian rhythm matters most. Here is how to find yours.
SPEC.011
How to Improve Sleep Quality Without Buying Anything
You do not need a new mattress, supplements, or gadgets to sleep better. Here are the free, evidence-based habits that actually improve sleep quality.
SPEC.012
Why Most Sleep Apps Upload Your Data (and What to Use Instead)
Most sleep apps upload your nightly data to the cloud. Here is why they do it, what it costs you, and the on-device alternatives that skip the cloud entirely.
SPEC.013
Sleep Tracking and Privacy: Where Your Sleep Data Goes
Most sleep apps upload your sleep data to the cloud. Here is what happens to it there, the real privacy risks, and how to keep your data on your device.
SPEC.014
How Much Deep Sleep Do You Really Need?
Chasing a deep sleep target is less useful than you think. Here is how much deep sleep adults typically get, what actually drives it, and how to read your own sleep data.
SPEC.015
REM vs Deep Sleep: What Each Stage Does for Your Brain
Deep sleep restores your body and consolidates memory; REM sleep processes emotions and powers dreaming. Here is what each stage does for your brain.
SPEC.016
What Is Sleep Debt and Can You Actually Repay It?
Sleep debt is the gap between the sleep you need and what you get. Here is what research says about naps, weekends, and catch-up sleep repaying it.
SPEC.017
Circadian Rhythm Explained: The Science of Sleep Timing
Your circadian rhythm is the internal clock that times your sleep. Here is how it works, what disrupts it, and how to get back in sync.
SPEC.018
Can Your Phone Detect Snoring? How It Works
Your phone's microphone can detect snoring and map when it happens overnight. Here is how snore detection works, its limits, and how to set it up.
SPEC.019
How Phones Detect Sleep With Just an Accelerometer
How does a phone know when you fall asleep? A look at how accelerometer sleep detection works, what it measures well, and its honest limits.
SPEC.020
What Is a Hypnogram? How to Read Your Sleep Stages
A hypnogram is a step graph of your night's sleep stages. Learn what the lines mean, what healthy patterns look like, and how to read your own sleep graph.
SPEC.021
Phone vs Smartwatch Sleep Tracking: Which Is More Accurate?
Your phone and your smartwatch both claim to track sleep, but they measure it in completely different ways. Here is an honest comparison of what each one gets right.
SPEC.022
How to Track Sleep Without a Wearable in 2026
Your phone's motion and sound sensors can map your sleep windows with no watch or ring required. Here's how on-device sleep tracking actually works in 2026.
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