Open-ended & multi-day fasts

What “open-ended” means here

Open-ended means the timer keeps counting without a forced stop and without asking you to pay. You can still set a goal (16 hours, 24 hours, a custom target) if you want a ring to fill. You can also run with no goal. The hour buttons are Presets on this clock. This page is still why the cap is gone.

The stage names keep moving as hours pass. They are not proof that a biological switch flipped. Read What the stages on the timer mean before you treat “Autophagy Window” as a destination.

Ending early is always allowed. The End Fast button is the most important control on a long session.

A long fast is not two 16:8s stacked

A daily eating window still includes food every day. A 36, 48, or 72 hour stretch does not. Hydration, electrolytes, sleep, medications, and how you refeed all change. Water and minerals past a day is the mineral note for a stretch past a day. Hydration and electrolytes stays daily windows. Breaking a fast gently is the landing.

Human trials of alternate-day and prolonged fasting are fewer, shorter, and more often supervised than headlines suggest. Read Alternate-day and prolonged fasting studies before you treat a 72-hour preset as “what the science says.” Nineteenth- and twentieth-century clinics packaged long fasts as treatment; that history is Therapeutic fasting in the 19th–20th centuries, not a ladder after 16:8.

Social media “water fasts” and app badges are a weak basis for an unsupervised project at home. If you do not already have a clinician who knows you, do not start with a multi-day target.

Who should not use the long presets as a first step

Anyone in Who should be careful should not use 36h, 48h, or open-ended as a beginner setting. Those presets exist so people who already have a plan can time it. They are not a ladder after 16:8.

If you are new, start near the overnight gap you already have. How to start fasting is day one. If you already mean a stretch past a day, Before a longer fast is that on-ramp. This page is still why Open exists.

If you feel worse as hours accumulate (dizziness, confusion, chest pain, fainting, severe weakness), stop. Eat. Get help. No badge is worth those signals.

How to use unlimited without turning it into a dare

Write the plan before you press Start: why this length, when you will stop even if you “feel fine,” and who you will tell. A plan you can explain in one sentence is safer than a mood.

Keep water nearby. Keep an exit. Do not add heat, hard training, or alcohol as extra challenges.

Use History as a log, not a leaderboard. This product will not rank you against friends by hours fasted.

The how-to cluster for a stretch you already mean is Longer fasts. If you already mean many days, Very long fasts is the companion, not a dare. This page is the product stance: no time cap is flexibility, not a ward.