Use Case: Sleep
Find your optimal sleep duration
The Problem
Sleep trackers tell you how long you slept and estimate sleep stages, but they don't measure the actual cognitive impact. You might feel fine on 6 hours, but is your brain actually performing well?
The Solution
Thalen directly measures next-day cognitive performance. Correlate sleep duration with your score: '7.5h = 1680, 6h = 1475.' Find your personal optimum with real numbers.
How It Works
How to optimize your sleep
Use objective cognitive data to find your ideal sleep duration.
Test at the same time each morning
Complete your Thalen session within 30 minutes of waking, before caffeine. This captures your cognitive state as directly influenced by the previous night's sleep.
Log your sleep duration
Note how many hours you slept the night before. You can use a sleep tracker or simple self-report. The key is consistency in how you measure.
Collect data across different sleep amounts
Over 2-4 weeks, you'll naturally have nights of varying sleep duration. Let the data accumulate rather than forcing artificial sleep deprivation.
Find your cognitive optimum
Correlate sleep hours with your composite cognitive score. Most people find a specific range (e.g., 7-7.5 hours) where performance peaks, not necessarily the most sleep.
Real Data
Discovering that 7.5 hours = +100 points
A user tracked their cognitive performance alongside sleep duration for 6 weeks. They expected more sleep would always be better, but the data revealed a clear optimum at 7.5 hours, with diminishing returns beyond that.
| Metric | Before | After | Change |
|---|---|---|---|
| 6 hours sleep | User avg: 1580 | 1475 | -105 points |
| 7 hours sleep | User avg: 1580 | 1595 | +15 points |
| 7.5 hours sleep | User avg: 1580 | 1680 | +100 points |
| 8+ hours sleep | User avg: 1580 | 1600 | +20 points |
Key Insight
The user's Thalen Score peaked after 7.5 hours of sleep: 1680 vs 1600 for 8+ hours. That 80-point difference is meaningful. It's the gap between solid Potent and approaching Coherent territory. They reclaimed 30 minutes each day with data Oura couldn't provide.
This is a hypothetical example for illustration. Individual results vary based on baseline, consistency, and intervention.
The Science
Why cognitive testing beats sleep trackers
Sleep trackers measure sleep. Thalen measures what you actually care about: cognitive performance. These aren't the same thing.
According to Van Dongen et al. (2003), individuals show significant variation in their vulnerability to sleep deprivation. Some people function well on 6 hours; others need 9. Population averages don't apply to you specifically.
"Substantial inter-individual differences exist in the degree of cognitive performance impairment experienced as a result of sleep loss."
Your Oura ring can't tell you whether your brain is actually performing well. Only direct cognitive measurement can answer that question.
What to Track
Sleep variables that affect cognition
Total Sleep Duration
The most impactful variable. Even 30 minutes less than your optimum can show up in PVT lapses the next day.
Sleep Timing
Same duration, different times. Test whether 11pm-7am performs differently than 1am-9am for you.
Sleep Consistency
Irregular sleep schedules (social jet lag) can impair cognition even when total hours are adequate.
Sleep Debt Recovery
How many nights of good sleep does it take to recover from one bad night? Your data will tell you.
Get early access.
Thalen is coming to iOS first. Join the TestFlight beta and start building your cognitive baseline.
Free. Your data stays on your device. No account required.