Circadian Rhythm & Sleep: ARC

You are not lazy at 3pm. You are running on a clock nobody showed you.

ARC works out the shape of your day — when your energy peaks, when it drops, and when a coffee stops being a good idea — then plans around it. Not a generic routine. Yours, built from what you actually log.

ONE ANSWER, NOT A DASHBOARD

Open the app and there is one sentence explaining why you feel like this right now, and one thing worth doing about it. Underneath, the rest of your day as a plan you can work through. Nothing else competes for your attention.

The plan is not a schedule. Log a walk and its block closes. Miss your morning light and a compensatory walk appears that was not there at breakfast. Report a low before the app expected one and the whole afternoon re-times.

YOUR LAST SAFE COFFEE, ACTUALLY CALCULATED

Most apps give you a rule of thumb. ARC solves for the latest moment a drink your size still clears your system before bed — from your bedtime, how fast you personally metabolise caffeine, and everything you have already had today.

Two people with the same bedtime and the same cup can get cutoffs three hours apart. That is not a bug. That is the point.

IT CHANGES ITS MIND ABOUT YOU

You tell ARC when you crash. After about ten days of check-ins it stops taking your word for it and uses the hour you actually crash — and it tells you when the
two turn out to differ. Everything timed around your dip moves with it.

PROOF, NOT PROMISES

The Trends tab is the receipt for everything the app has told you: your crashes per week, whether the number is falling, when your dip really lands, and what each
habit changed. Every claim is built from your own check-ins and each one knows whether it has enough history to mean anything. When it does not, it says so
instead of drawing a line through three points.

ONE CHANGE, FIVE DAYS

Every so often ARC proposes a single experiment — an earlier cutoff, light before nine, a walk before your dip — runs it for five days, and scores it against the fortnight before. "No difference" is one of the possible verdicts, and it is a real result: it takes something off your list for good.

LEARN

23 briefings on light, caffeine, sleep and timing, in English and German. A reference you go to, not a feed pushed at you.

WHAT IT DOES NOT DO

No sleep score. No streaks. No badges. No congratulating you. The app will tell you that you slept badly; it will never tell you that you are doing badly.

No account. No login. No wearable required. Your history lives on your phone.

REQUIRES

iPhone. Notifications are optional. Location is never requested — sunrise comes
from your time zone.

ARC is a wellness app. It is not a medical device and does not diagnose, treat or
prevent anything.

SUBSCRIPTION

ARC Pro unlocks the full app after setup: the daily plan, the caffeine cutoff,
Trends, the weekly experiments and Learn.

• ARC Pro – Weekly: $4.99 per week
• ARC Pro – Annual: $39.99 per year with 7 days free trial

Payment is charged to your Apple Account at confirmation of purchase. Subscriptions renew automatically unless auto-renew is turned off at least 24 hours before the end of the current period. Your account is charged for renewal within 24 hours of the end of the current period. You can manage or cancel your subscription in your Apple Account settings, or from Settings inside the app. Any unused portion of a free trial is forfeited when you buy a subscription.

Privacy Policy: https://arcapp.sbs/privacy
Terms of Use: https://arcapp.sbs/terms