Reflex – Reaction Test
Carsten Schaal Health & Fitness iPhoneiPadiPod touch
Reflex – Reaction Test is a free Health & Fitness app for iPhone and iPad by Carsten Schaal. Requires iOS 18.0. Updated September 25, 2026.
- Price
- Free
- on the App Store
- Size
- 2 MB
- Age 4+
- Updated
- Sep 25
- 2026 · v1.01
Screenshots
About Reflex – Reaction Test
Reflex measures in 20 seconds how sharp your mind is today – and shows you over weeks what really affects your reactions: sleep, activity, resting heart rate, HRV, coffee or exercise. One test a day, one number, one clear picture. NO ACCOUNT. NO TRACKING. NO ADS. All data stays on your device. Apple Health is only read, never shared and never stored in iCloud. The daily test is free and always will be. 20 SECONDS A DAY Tap as soon as the screen turns green – as fast as you can. Reflex measures the moment your finger touches the screen, detects false starts and lapses, and takes the median of all reactions. The method is a compact form of the Psychomotor Vigilance Task that sleep researchers use to measure alertness. YOUR DAY AT A GLANCE The Today tab shows your score compared to your 7-day average, your streak, your best and the day's health context: last night's sleep, yesterday's steps, resting heart rate, HRV and when you woke up. HISTORY OVER WEEKS Trend chart with moving average and personal best, every session with all trials in detail. A weekly recap sums up average, best day and the comparison to last week – shareable as an image. WHAT MAKES YOU FASTER After seven days with data, Reflex calculates the relationship between your reaction time and each health metric: "From 7 h of sleep: 8% faster." Not from studies, but from your own numbers. EXPERIMENTS Tag days with coffee, alcohol, exercise, stress or little sleep – and see what makes the difference for you. DAILY FORECAST In the morning, Reflex predicts from your sleep and heart data what today has in store. After the test you see whether you did better than expected. WIDGET, SIRI, REMINDER Home and Lock Screen widgets with today's score and streak, the "Start Reflex test" shortcut for Siri and the Action button, and a daily reminder only on days you haven't tested yet. REFLEX PRO – €7.99 PER YEAR OR €19.99 ONCE • All insights in detail: steps, resting heart rate, HRV, time since waking • Daily forecast "expected vs. actual" • Experiments: with and without coffee, exercise, alcohol • Patterns by weekday and time of day • Unlimited history, CSV export, weekly recap as an image • iCloud sync of your test results across your devices The yearly plan starts with 7 days free. The sleep insight and the daily test always stay free. Reflex is not a medical device. Its analyses show relationships in your own data and do not replace medical advice. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy: https://csappworks.de/reflex/datenschutz
What’s new
Version 1.01 · Updated September 25, 2026
Bugfixe
App privacy
The developer, Carsten Schaal, reported these privacy practices to Apple.
Data Not Collected
The developer does not collect any data from this app.
Alternatives to Reflex – Reaction Test
Looking for apps like Reflex – Reaction Test? Here are 6 similar apps on the App Store. The highest rated is CogniTrack: Reaction Time Test (5.0/5), and 5 of the 6 are free to download.
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| App | Rating | Price | Last updated | Compare |
|---|---|---|---|---|
| Reflex – Reaction Test | – | Free | September 25, 2026 | |
| CogniTrack: Reaction Time Test | 5.0 / 5 (2) | Free | Mar 23, 2026 | Compare |
| Step Stats - Pedometer | 4.3 / 5 (31) | Free | Mar 26, 2026 | Compare |
| Stress Tracker HRV | 5.0 / 5 (2) | 7.99 USD | May 20, 2026 | Compare |
| Nutrelino: More Than Calories | 5.0 / 5 (2) | Free | Jun 7, 2026 | Compare |
| NASA PVT+ | 4.8 / 5 (10) | Free | Dec 9, 2025 | Compare |
| 100 Squats: Butt & Leg Trainer | 4.9 / 5 (132) | Free | Oct 19, 2026 | Compare |