Your Whoop can tell you your nervous system is stressed. It can't tell you your reaction time is 80ms slower than yesterday. BASLN measures your brain directly with six research-validated cognitive tests. Five minutes. Every morning.
Free for first 10 sessions · End-to-end encrypted in iCloud
HRV, sleep stages, and respiratory rate tell you about your autonomic state. They don't tell you how fast you react, how much you remember, or how well you focus. Those require cognitive tests.
Each test is a compressed version of an instrument used in peer-reviewed cognitive research. Together they cover the core dimensions of operational cognitive performance.
Reaction time · Vigilance
Tap the moment a counter appears. No learning effect. The gold-standard measure of fatigue in sleep deprivation research.
Run on the ISS as the astronaut Reaction Self-Test. Used in thousands of peer-reviewed sleep studies.
Working memory
Watch a shape appear in one of 9 positions. Report when the current position matches the one two steps ago.
The spatial N-back paradigm is a canonical working-memory task, validated in neuroimaging work by Jonides et al. (1993). NASA's Cognition battery uses a fractal-identity variant for spaceflight research.
Processing speed
Match digits to symbols as fast as possible against a reference key. The single best predictor of complex operational performance.
In NASA-funded research, DSST average response time explained 34% of the variance in simulated 6DF spacecraft docking performance.
Executive function · Inhibitory control
Identify the color a word is printed in, not the word itself. Measures your ability to override automatic responses.
One of the most validated executive-function instruments in experimental psychology.
Processing speed under load
Verify whether simple equations are true or false, under time pressure. A compact proxy for cognitive throughput.
Serial addition / subtraction tasks have been a core component of operational cognitive batteries since the Walter Reed Performance Assessment Battery (WRPAB).
Cognitive flexibility · Task switching
Connect alternating numbers and letters as fast as possible. Measures the cost of switching rules on the fly.
Core measure in clinical neuropsychology since Reitan (1958).
BASLN has no servers. We collect nothing. Zero analytics, zero tracking, no accounts. Your cognitive history stays in your private iCloud, end-to-end encrypted.
The same experimental loop used in operational fatigue research, compressed for daily use on your phone.
Take the battery once a morning for five sessions. BASLN learns your personal cognitive signature across the six dimensions.
Every subsequent session scores you 0–100 against your own norm. No population percentiles. Just you versus you.
Low score? The app surfaces evidence-ranked recovery protocols (caffeine timing, bright light, HIIT, nap) with time-to-effect estimates and citations.
Retest later in the day. See whether the intervention actually moved your numbers, or whether you were placebo-ing yourself.
BASLN gets more useful the longer you keep logging. Every session sharpens your baseline. Every week adds signal.
BASLN gives you your first readiness reading. Early scores are directional more than definitive; the Starting Baseline keeps sharpening through session 21.
21 days of data in your rolling window. The baseline continues rolling forward, sensitive to real changes in sleep, stress, or the interventions you're testing on yourself.
Enough sample size for statistics to bite. Cold plunge, creatine, late caffeine. The things you track stop being anecdotes and start being signal.
Your weekday rhythm. Your worst month. Your morning peak. Patterns that only become visible with a full year of honest data.
A longitudinal record of your own cognition that no wearable, no doctor, no device has ever captured for you.
A missed week is a week-shaped hole in your record that can't be refilled.
Baseline for a week. Start an intervention. Test daily. Watch the number move, or don't. Either way, you have data.
iPhone · iOS 17+ · End-to-end encrypted in iCloud