CalmTide: Cortisol Tracker

Stress, HRV & Recovery Score

Free · In‑App Purchases

CalmTide 1.8: NSDR, a cold finish and a post-meal walk join the breathing practices — and your Apple Watch now shows your heart rate as you breathe. CalmTide estimates stress load from your Apple Health data — it does not measure cortisol. See your stress load clearly. CalmTide reads the Apple Health data you already have — sleep, HRV, workouts, resting heart rate, mindful minutes — and turns it into one clear picture of your stress biology: an HPA Balance Score today, and an estimated 8-week trend. Everything runs on your device. No account, no cloud, no analytics. Your health data never leaves your phone. SEE TODAY CLEARLY • HPA Balance Score (0–100) from a named, citation-backed model — tap any number to see the research behind it • Pick a focus — less stress, better sleep, avoiding burnout or training without overtraining — and Today and Insights lead with it • A daily protocol checklist: breathwork, Zone 2, sleep, morning light • Recovery signals at a glance: HRV, resting heart rate, sleep, breathing rate • Your HRV and resting heart rate against typical ranges for your age and sex (Pro) FIND YOUR PATTERNS • Morning-after insights: what caffeine, alcohol, late meals and hard workouts did to your HRV, sleep and readiness — read when the biology lands • What your check-ins reveal (Pro): whether how you feel tracks your sleep, HRV and training • Which of your habits your load estimate moves with, from your own data — suggestive, not causal, and always explained UNDERSTAND YOUR WEEK • A weekly retrospective that ranks what moved your score — sleep, morning light, HRV, mindfulness, training load — in points, this week versus last (Pro) • Workouts with heart-rate data scored for their cortisol effect: reducing, neutral or spiking. Sessions without it still count toward your weekly dose, never guessed at • Training load as plain figures: acute-to-chronic ratio, monotony and strain (Pro) ACT ON IT • Practice hub: cyclic sighing (Balban 2023) and resonance breathing (Steffen 2020), in 2, 5 or 10-minute doses, suggested for the moment you're in • More practices (Pro): NSDR / yoga nidra, a short cold finish for the morning, and a post-meal walk — each guided, each naming the study behind it • Breathing sessions count down on your Lock Screen and in the Dynamic Island • Completed breathing and NSDR sessions save to Apple Health as Mindful Minutes • Morning-light coaching to anchor the body clock that times your morning cortisol rise YOUR 8-WEEK TREND • An estimated 8-week trend with your life events pinned to it — illness, travel, deadlines — so shifts make sense • A 7-day cortisol forecast from your training and sleep (Pro) • Share cards for your trend, your month and your season, numbers off by default (Pro) • A PDF summary and CSV export of your weeks, to bring to an appointment (Pro) ON YOUR WRIST, AND BY VOICE • Apple Watch: your balance as a complication or in the Smart Stack, haptic-paced breathing with your live heart rate on screen, and check-ins that sync back to your iPhone • Training readiness on the watch, before you work out (Pro) • Ask Siri "What's my cortisol today in CalmTide?" for today's status and weekly balance (Pro) • Start a breathing session from Control Center, the Action button or Siri PRIVATE BY DESIGN • On-device analysis, including the optional Calm Coach explainer • Export or restore your data any time — it's yours • App Privacy label: Data Not Collected CalmTide is free to use daily. CalmTide Pro unlocks everything marked (Pro), plus the full 8-week trend, 60- and 90-day history, score & forecast widgets, scores on Apple Watch and Calm Coach — as a monthly or annual subscription, or a one-time lifetime purchase. The annual subscription includes a 1-month free trial for new subscribers. Subscriptions auto-renew until cancelled; the price and any trial are shown before you confirm. CalmTide is a wellness tool. It does not diagnose or treat any medical condition. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://twisteddatastudios.com/calmtide-privacy.html

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CalmTide 1.8: more to do, and more places to do it. • A practice library (Pro). NSDR / yoga nidra, a short cold finish and a post-meal walk join cyclic sighing and resonance breathing. Each is guided with a timer, names the study behind it and says when it suits — the cold finish is a stimulus, so it belongs early in the day, never before bed. The practice card suggests one for the moment you're in. • More of your Apple Health data. VO₂ max, weight, blood oxygen, breathing rate, walking heart rate, time in daylight, environmental sound and stand time are now requested alongside your core metrics, so the Insights cards built on them fill in. Already set up? Insights shows a one-tap prompt to allow them. VO₂ max and weight now look back 90 days, so occasional weigh-ins still draw a trend. • Live heart rate on your wrist. Breathing on Apple Watch now shows your heart rate as you go, so you can watch it settle. It uses a short mind-and-body session that ends with your practice — no workout is saved to Health. • Training readiness on Apple Watch (Pro), and a Smart Stack card that surfaces CalmTide around waking and bedtime. • Live Activities. A breathing session counts down on your Lock Screen and in the Dynamic Island, and pauses if you leave the app. With training alerts on, a recovery window after a hard session shows how long a short breathing session still suits. • Ask Siri "What's my cortisol today in CalmTide?" for today's status and your weekly balance (Pro). It answers only from a recent reading, and says so when yours is out of date. • Choose a focus — lower daily stress, sleep better, avoid burnout, or train without overtraining. Today and Insights lead with the cards that serve it, and reminders start from sensible defaults for it. • Reminders that don't wear thin: the wording rotates, and a reminder you keep ignoring backs off on its own. Settings shows anything paused, with one tap to resume. • Share your trend, your month or your season as a card, with numbers off by default (Pro). • A PDF summary and CSV export of your weeks, to bring to an appointment (Pro). • Corrections: the cold-exposure description now says what its study measured — a sharp rise in noradrenaline, not cortisol — and the methodology no longer describes HRV with a superlative. • Plus fixes from three rounds of review across Live Activities, reminders, Pro features and the report. Everything runs on your device. CalmTide is a wellness tool and does not diagnose or treat any medical condition.

The developer, Michael Smith, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Seller
    Michael Smith
    Size
    9.9 MB
    Category
    Health & Fitness
    Compatibility
    Requires iOS 18.6 or later.
    • iPhone
      Requires iOS 18.6 or later.
    • iPad
      Requires iPadOS 18.6 or later.
    • Apple Watch
      Requires watchOS 11.0 or later.
    Languages
    English and 3 more
    • English, German, Japanese, Spanish
    Age Rating
    13+
    • 13+
    • Infrequent
      Medical Treatment information
    In-App Purchases
    Yes
    • Annual $29.99
    • Monthly $4.99
    • Lifetime $59.99
    Copyright
    © 2026 Twisted Data Studios