# Kairis: Circadian Rhythm — Your day, perfectly calibrated

> Your day, perfectly calibrated (iPhone/iPad app by Vladimir Olexa.)

- Source: https://appshunter.io/ios/app/kairis-circadian-rhythm/id6759058817 (this page in markdown: same URL + `.md`)
- Developer: [Vladimir Olexa](https://appshunter.io/developer/1726966629)
- Category: Health & Fitness, Lifestyle
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 18.6 · 77 MB
- Languages: English
- Released: 2026-04-20
- Data updated: 2026-06-28
- User reviews in markdown: https://appshunter.io/ios/app/kairis-circadian-rhythm/id6759058817/reviews.md

## What is Kairis?

Free Circadian Clock + iPhone widgets. See when your body is primed for deep work, training, and rest — minute by minute, powered by the cosinor model. Sync compatible health data from Apple Health to personalize your experience.

Kairis is not a habit tracker. It's a biological timing system, built for people who want to operate at peak capacity — consistently, deliberately, and in sync with their physiology.

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THE CIRCADIAN CLOCK (FREE)

Visualize your day in biological time. The clock maps how your body shifts hour by hour:

• Performance: alertness, reaction time, coordination, muscle strength, cardiovascular efficiency
• Metabolism: blood pressure, body temperature, heart rate, glucose tolerance
• Hormones: melatonin, testosterone, cortisol, growth hormone
• Restoration: pulmonary function, sleep propensity, digestive rhythm
• Sleep & wake cycle: stages (N1, N2, N3, REM), positioning, time to bedtime, time to wake

Powered by the cosinor model — the statistical method used in chronobiology research — for sharp, smooth, individualized daily curves.

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APPLE HEALTH

Connect Apple Health to automatically import compatible health data.

• Use Apple Health sleep data to personalize your Circadian Clock
• Sync supported workouts, mindfulness sessions, heart rate, and other health metrics
• Reduce manual tracking and keep your data up to date across apps

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HOME SCREEN WIDGETS (FREE)

Your circadian state, always visible. Track your performance window, sleep cycle stage, hormone levels, and time-to-bedtime directly on your Home Screen — without opening the app.

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EXTERNAL CONDITIONS

Your biology responds to the environment. Monitor what's shaping your rhythms:

• Solar patterns: day length, sunrise, sunset
• Lunar cycle: current phase with visual indicator
• Atmospheric: temperature and UV index

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PROTOCOLS FOR LIFE

Turn insight into action. Structure your day with protocols mapped to your biology:

• Morning, afternoon, and evening routines
• Focused work blocks
• Training sessions
• Recovery periods
• Bedtime wind-down

Recurring schedules, configurable notifications, a clean execution system. Think of it as a configurable daily plan that runs in lockstep with your physiology.

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MINDFULNESS

• Breathing: physiological sigh, box breathing, cyclic hyperventilation, 4-7-8 — calibrated to your lung capacity with precise inhale, exhale, and hold control
• Meditation: focused attention, open monitoring, reflective, generative — guided or unguided, 1 minute to 1 hour
• Yoga Nidra: full sessions for deep rest and NSDR
• Journaling: AI-generated prompts (where supported) plus curated libraries across four categories

Background audio, ambient sounds (nature, ocean, white/pink/brown noise), binaural beats, multiple gong styles. Every session is fully configurable.

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TRACK WHAT FUELS PERFORMANCE

Monitor the inputs that shape your biology — manually or through supported Apple Health integrations:

• Light exposure
• Sleep quality
• Cardio, resistance, breathing, and meditation minutes
• Social interactions (dyadic, triadic, group, familial)
• Internal interactions (emotional processing, cognitive restructuring, appreciation, intentions)

Daily goals with visual streaks that reflect real physiological support — not arbitrary habits.

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Kairis is built for operators, athletes, and anyone who wants to work with their physiology instead of against it.

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Terms of Use: https://www.kairis.app/terms
Privacy Policy: https://www.kairis.app/privacy
Support: https://www.kairis.app/support

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Kairis Monthly | $12.99 | per month |
| Kairis Annual | $89.99 | per year |

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Kairis Lifetime | $199.99 | one-time |



## Version history (last 2 releases)

### 1.2 — 2026-06-13

v1.2 — Apple Health integration

• New Apple Health integration syncs compatible health data with Kairis
• Import sleep, workouts, mindfulness sessions, heart rate, and other supported Health metrics automatically
• Circadian Clock can use Apple Health sleep data to personalize daily biological rhythms
• Home Screen widgets bring live circadian insights to your Home Screen
• Circadian Clock, powered by the cosinor model, tracking alertness, sleep stages, hormone levels, restorative functions, and more
• Performance and stability improvements

The Circadian Clock and all widgets remain free to use.

### 1.0 — 2026-04-20

No release notes.

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-28.*