Qronos: Charge, Load & Sleep

Qronos turns the data from your fitness tracker into three simple daily scores: Charge, Load and Sleep. See how ready you are each morning, how hard you pushed during the day and how well you slept, all in one place.

Qronos works best with Fitbit Air and equivalent trackers. It connects to Google Health (through Health Connect) to read your heart rate, sleep, steps and workouts.

PRIVATE BY DESIGN
All of your data is processed on your phone. Nothing is sent to or processed on any server. Qronos has no account, no ads and no analytics, and the app does not even request internet access. Your history stays in the app's private storage until you delete it.

CHARGE
One clear reading each morning, set when your sleep comes in. Charge compares last night's resting heart rate, heart-rate variability and sleep with your own baseline, so it reflects you and not an average person.

LOAD
A 0 to 21 scale of how much your heart worked today, from all-day activity and workouts. Load builds gradually through the day and the ring shifts from green to yellow as you push harder.

SLEEP
How much you slept compared with what your body needed, based on your sleep goal, recent sleep debt and the day's Load. See your sleep stages each night, and get a suggested bedtime based on your usual wake time.

ALWAYS LEARNING
Qronos calibrates from your first few nights and keeps adapting to you every day. No manual setup or heart-rate entry is needed.

MORE FEATURES
- Dashboard with weekly charts of Charge, Load, Sleep and heart rate
- Biometric Age: a weekly estimate built from six months of your sleep, activity and fitness habits
- Activity details with heart-rate zones and graphs
- Automatic activity detection, plus your recent workouts from Google Health
- Quick activity logging with dozens of activity types
- Bedtime reminder and a 10 PM daily summary
- Home-screen widgets
- Encrypted backup to Google Drive or your phone, with daily automatic backup, so you can restore everything on a new phone
- Export your data to JSON or CSV at any time

GET THE BEST RESULTS
Go to Google Health → Partner apps → Qronos and enable all permissions to get better Charge and Load results. Heart-rate variability, resting heart rate and sleep stages make the biggest difference. Wear your tracker day and night, including while you sleep. To keep widgets up to date, set Qronos's battery usage to Unrestricted in Android settings.

PLEASE NOTE
Qronos is a fitness and wellness app. It is not a medical device and does not diagnose, treat or prevent any condition. Talk to a doctor about any health concerns.
Qronos is an independent app and is not affiliated with or endorsed by Google or Fitbit. Fitbit and Google Health are trademarks of Google LLC.

Recent changes:
Welcome to Qronos!
- Charge, Load and Sleep: three simple daily scores from your tracker
- Calculated entirely on your phone. No account, no ads, no internet access
- Dashboard, Biometric Age, activity details and home-screen widgets
- Bedtime reminder and 10 PM daily summary
- Encrypted backup to Google Drive or your phone
Tip: Google Health → Partner apps → Qronos → enable all permissions for best results.