CalmTide: Cortisol Tracker

Lower your baseline cortisol. 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 baseline-cortisol trend over 8 weeks. Not another meditation timer. A measurement layer for calm.

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
• One smart recommendation, chosen for today — not a generic list
• A daily protocol checklist: breathwork, Zone 2, sleep, morning light
• Recovery signals at a glance: HRV, resting heart rate, sleep, respiratory rate
• Where you sit against normative ranges for your age — free, on every metric

FIND YOUR PATTERNS (new in 1.5)
• Morning-after insights: what caffeine, alcohol, late meals and hard workouts did to your HRV, sleep and readiness — read the next morning, when the biology actually lands
• What your check-ins reveal (Pro): whether how you feel actually tracks your sleep, HRV and training, compared across your own days
• Your strongest cortisol link, from your own data — suggestive, not causal, and always explained
• Personal records: longest streak, best HPA week, calmest morning

UNDERSTAND YOUR WEEK (new in 1.5)
• A weekly retrospective that ranks exactly what moved your score — sleep, morning light, HRV, mindfulness, training load — in points, this week versus last
• Every workout scored for its cortisol effect: reducing, neutral, or spiking
• Training-load intelligence: 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 by situation — evening wind-down, post-workout, elevated load
• Completed sessions save to Apple Health as Mindful Minutes
• Morning-light coaching to anchor your cortisol awakening rhythm
• Smart, quiet notifications that arrive when they help — never to interrupt

WATCH YOUR BASELINE FALL
• An 8-week estimated baseline-cortisol 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)
• Check in from your wrist with the Apple Watch app (new in 1.5)

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 (full 8-week trend, extended 60- and 90-day history, the cortisol forecast, score & forecast widgets, scores on Apple Watch, advanced training-load analytics and Calm Coach) is available as a monthly or annual subscription, or a one-time lifetime purchase. New subscribers get a 1-month free trial. Subscriptions auto-renew until cancelled; the price and any trial are shown before you confirm.

CalmTide is a wellness tool. It estimates — it does not measure cortisol, and it does not diagnose or treat any medical condition.