Zing Sessions vs Sleep Ledger
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Zing Sessions
Enhance cognitive and physical performance with personalized exercises designed to boost brainpower. This mobile app offers on-screen skill tests and physical activities based on neuroscience research to improve attention, memory, and coordination.
- On-the-go accessibility
- Personalized exercise programs
- Cognitive, emotional, and social performance training
- Improved attention and memory
- Enhanced coordination and spatial awareness
- Stress management benefits
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A light version of the full app. This app has been designed to help you complete your exercises whilst on the go as it can be downloaded to a mobile or tablet to complete your sessions. Neuroscience is constantly evolving to show us how to increase our brainpower. At Zing Performance we’re passionate about bringing this possibility to EVERYONE. The Zing Performance programs are made up of on-screen skill tests and a personalized range of simple physical activities, that together, are designed to support and strengthen key parts of your brain. Research shows that stimulating specific parts of the brain using carefully chosen coordinative exercises can increase its speed and efficiency. Using this research, Zing Performance has developed a personalized online program made up of balance exercises to help improve your overall mental and physical performance. Through the brain-body connection it brings benefits to your everyday life – at school, at work, at home, and in your sports and hobbies. FEATURES: - Specifically designed to be easily accessible from anywhere when on the go. - Over 200 exercises personalized for your current development needs using our advanced algorithm. - Sleek and elegant design with fluid and lifelike animations. - Programs targeting and refining cognitive, emotional and social performance in personal and professional life. POTENTIAL RESULTS: - Stimulating the part of the brain responsible for attention, memory and coordination, making it more efficient and automatic. - Creating a balance between a fit body and mind, allowing for a more efficient management of stress. - Absorbing knowledge swiftly while effectively determining and selecting important sections of information when needed. - A greater and more precise spatial awareness. For more information, visit our website www.zingperformance.com. Download today to start your Zing Performance journey!
Sleep Ledger
This app analyzes your sleep data from Apple Health to calculate your sleep debt and provides a personalized daily plan to help you recover. It offers insights into sleep quality and a clear path to reaching your sleep goals.
- Sleep debt calculation
- Personalized recovery plan
- Quality-weighted sleep score
- Calendar-based schedule
- Lock screen widgets
- On-device processing
- Siri Shortcuts
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Are you running on a sleep deficit? Sleep Ledger reads your Apple Health sleep data to calculate how much sleep you owe your body — and builds a personalized, day-by-day recovery plan to help you pay it back. WHAT MAKES SLEEP LEDGER DIFFERENT Unlike other sleep apps that drown you in data, Sleep Ledger gives you two things: a number (your sleep debt) and a plan (when to go to bed tonight). - Quality-Weighted Debt Score Not just hours — Sleep Ledger uses Apple Watch sleep stage data (Deep, REM, Core) to calculate how effective your sleep really was. Six hours of deep, restorative sleep counts differently than eight hours of restless tossing. - Calendar Recovery Plan See exactly when you'll be debt-free. Sleep Ledger generates a day-by-day schedule with recommended bedtimes, adjustable for late nights and per-weekday wake times. - Lock Screen, Home Screen & Apple Watch Complications Your debt balance and tonight's bedtime — always one glance away on your lock screen, home screen, or watch face, without opening the app. - Private by Design, On-Device Processing No account creation. No analytics SDKs. No advertising code. No third-party trackers. Your sleep, heart rate, and HRV data is processed entirely on your device. The only network request happens when you choose to send us feedback from Settings → Contact, and the diagnostic details are shown in the form before you send them. HOW IT WORKS 1. Download and grant read access to Apple Health sleep data. 2. Sleep Ledger analyzes your past 14 days of sleep history. 3. See your current sleep debt balance instantly. 4. Follow your personalized recovery plan to reach zero debt. FEATURES Free: - Sleep debt calculation (14-day rolling window) - Recommended bedtime based on your wake time and current debt - Manual sleep entry (add, edit, delete nights) - Lock Screen widgets (debt balance & recovery gauge) - Home Screen widget, Small (debt balance + days to zero) - Apple Watch complications (circular gauge, rectangular, corner) - Bedtime reminder and morning summary notifications - Siri Shortcuts (check debt, get bedtime, last night summary) - Works with or without Apple Watch - English, Japanese, German, French, and Korean Premium: - 14-day debt trend charts - Day-by-day recovery plan with target zero-debt date - Quality-weighted debt score (sleep stages + HRV) - Sleep stage breakdown (Deep / Core / REM) - Home Screen widget, Medium (debt · last night · bedtime) - Workouts & Sleep — workout timing vs. your sleep (optional permission) - CSV data export (date, duration, stages, HR/HRV) ABOUT SLEEP DEBT Sleep debt is the gap between the sleep your body needs and the sleep you actually get. Research shows that accumulated sleep debt affects energy, mood, focus, and long-term health. The good news: you can pay it back. Sleep Ledger shows you how. PRICING Sleep Ledger is free to download. Core features — today's debt balance, tonight's bedtime recommendation, manual sleep entry, Lock Screen widgets, Apple Watch complications, and Small Home Screen widget — are always free. Premium unlocks the full recovery plan, sleep trend history, quality-weighted scoring, sleep stage breakdown, Home Screen Medium widget, and CSV data export. Annual plan includes a 2-week free trial. PRIVACY Sleep Ledger contains zero analytics SDKs, zero advertising code, and zero third-party trackers. Your sleep, heart rate, and HRV data is processed entirely on your device — it never leaves your iPhone. The only network request is triggered when you tap Settings → Contact to send feedback, and the full diagnostic payload (iOS version, device model, app version, HealthKit fetch status, Premium status) is visible in the form before you send it. We believe your health data belongs to you and only you. Note: Sleep Ledger is a general wellness app. It is not a medical device and is not intended to diagnose, treat, or prevent any disease. Consult a healthcare professional for medical concerns.
Screenshots
Verdict
The clearest difference is rating: Sleep Ledger at 5.0 against Zing Sessions's 2.9. Sleep Ledger also leads on update cadence (every 8 days vs every 4 months). Zing Sessions's advantage is in-app purchases (none vs 3) and ratings volume (17 vs 2). On price, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Sleep Ledger sells 3 in-app purchases, starting at $4.99 per month. Zing Sessions asks for nothing beyond the download.
Sleep Ledger holds the better App Store score, 5.0 against 2.9. That said, the two scores are not equally well evidenced: Zing Sessions has 17 ratings behind it against 2, so its average is the more settled of the two.
Zing Sessions ships an update every 4 months, Sleep Ledger every 8 days. The most recent releases landed on October 2, 2026 and October 8, 2026 respectively.
| Parameter | Zing Sessions | Sleep Ledger |
|---|---|---|
| Price | Free | Free |
| Rating | 2.9 (17 ratings) | 5.0 (2 ratings) — better |
| Positive reviews | 80.0% of reviews | — |
| Number of ratings | 17 — better | 2 |
| Update frequency | Every 4 months | Every 8 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Freemium |
| Devices | iPhone, iPad, iPod — better | iPhone, Apple Watch |
| Requires iOS | 13.0 — better | 18.0 |
| Further details — not scored | ||
| Size | 824 MB | 8 MB |
| Age rating | 17+ | 12+ |
| Developer | Zing Performance Ltd | Takumi Kanzaki |
Customer experience
Zing Sessions
Sleep Ledger
In-app purchases
Zing Sessions
No in-app purchases
Sleep Ledger
- Monthly$4.991 Month
- Annual14 Days trial$29.991 Year
- Lifetime$79.99









