Fasting Window vs Sleep Debt Tracker & Coach

Record your own fasting times, without an account. YOUR TIMES IN ONE WINDOW - Read your planned time to eat again, with its date - Correct an active start within the past 24 hours - Choose no goal to record elapsed time without a planned time - Keep your selected 16:8, 18:6, 20:4, OMAD or Custom preset (Custom is saved as 16 hours) - Receive a reminder at your chosen goal, when notifications are allowed - End at any time, including before your chosen goal KEEP YOUR RECORDS - See actual lengths and summaries from your last 90 records - Correct the end time of records that ended within the past 24 hours - Existing local records and settings are preserved SAFETY INFORMATION This is a time record, not a medical tool. It does not measure metabolism or provide medical advice. Goals are personal settings, not recommendations to fast longer. Talk with a healthcare professional before considering fasting, especially if you are under 25, pregnant or breastfeeding, take insulin or diabetes medicines, take medicines that require food, have a seizure disorder, work night shifts or operate heavy machinery. If you have or have had an eating disorder, avoid fasting and consult a healthcare professional. If you feel unwell, stop regardless of your goal and seek professional advice. Sources: NIH News in Health, To Fast or Not to Fast, December 2019; https://newsinhealth.nih.gov/2019/12/fast-or-not-fast Johns Hopkins Medicine, Intermittent Fasting: What is it, and how does it work?, updated April 7, 2026; https://www.hopkinsmedicine.org/health/wellness-and-prevention/intermittent-fasting-what-is-it-and-how-does-it-work

How much sleep did you really miss over the last 14 nights? This app reads the sleep in Apple Health, from your Apple Watch, another tracker or nights you enter yourself, and answers three questions: How much sleep debt do you have? How regular is your sleep? And what should you do tonight to pay it back? Every night you sleep a little less than you need, the shortfall quietly adds up. Research shows that two weeks of 6-hour nights can affect attention about as much as a night without sleep, and most people don't feel it. Your sleep debt makes that hidden shortfall visible, and the plan closes it night by night. TODAY • Sleep debt over the last 14 nights, recent nights counting more, with a clear level: Balanced, Mild, Moderate or High • A moon that fills as you catch up: the fuller the moon, the more rested you are • Tonight's recommended bedtime, wake-up time and last caffeine on one timeline • A catch-up plan built around your alarm, at a steady or fast pace: bedtime moves earlier step by step • Your sleep debt tomorrow morning if you follow the plan • Evidence-based notes, last night's summary and a 14-night chart RHYTHM • Sleep Regularity Index (SRI): how consistent your sleep timing is from day to day • Social jetlag: how your sleep shifts between workdays and days off • Chronotype: are you an early bird or a night owl? • Sleep window and debt trend charts MORNING REPORT AND REMINDERS • Morning report: once your watch has saved the night, last night against your need, how your debt changed and tonight's plan. On the first day of the week, a weekly summary. • Bedtime reminder, 15 to 60 minutes before your recommended bedtime • Last-caffeine reminder All of them are optional. WIDGETS AND APPLE WATCH • Home Screen and Lock Screen widgets with your sleep debt and tonight's plan • On Apple Watch: your debt and the moon, tonight's plan with a live countdown, the last 7 nights and today's notes • Watch face complications for your sleep debt and tonight's bedtime LEARN • 13 short articles: what sleep debt is, why we don't notice it, how to pay it back, finding your own sleep need, caffeine and sleep, smart napping, how accurate Apple Watch is, when to see a doctor, and more • Direct links to 27 scientific sources TUNED TO YOU • Sleep need by age group, adjustable • Your workday alarm and mornings without one • Caffeine habit: none, light, moderate or a lot • No Apple Watch? Enter your nights by hand, or use another sleep app SCIENCE-BASED AND TRANSPARENT Every calculation is grounded in peer-reviewed research: Van Dongen 2003, Kitamura 2016, Banks 2010, Phillips 2017, Windred 2024, Wittmann 2006, Roenneberg 2012, Gardiner 2023 and others. Sleep debt is calculated only from total sleep time and sleep timing, which Apple Watch measures reliably. Deep and REM stages are not used in any score, because stage accuracy on wearables is low. PRIVACY The app reads your sleep data from Apple Health, saves to it only the nights you enter yourself, and processes it on your iPhone and Apple Watch. No account, no ads, no tracking: your health data never leaves your devices. Apple Watch gives the most accurate results. The app also works with other devices and apps that save sleep to Apple Health, and with the nights you enter yourself. SLEEP DEBT PLUS Your sleep debt, tonight's plan, the morning report, the reminders, the widgets and the sleep debt pages and complications on Apple Watch are part of Sleep Debt Plus, an auto-renewing yearly or monthly subscription. Last night, your 14-night chart, your sleep rhythm and all articles are available without a subscription. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Not a medical device, and not intended for diagnosis or treatment. If you have ongoing fatigue, loud snoring or long-lasting sleep problems, talk to a doctor.