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HeartOxy helps you train smarter with your Apple Watch. It shows your heart rate on a live chart, alerts you when you move outside your target zone, and helps you stay at the right workout intensity without constantly checking your wrist.

Beyond your workout, HeartOxy also automatically calculates personalised heart-rate zones, provides Daily Readiness insights, saves every workout so you can review your progress over time, and lets you export your workout history as a CSV file.

No. HeartOxy works with your Apple Watch and iPhone. There's no additional wearable to buy, wear or charge.

Not at all. Choose your heart-rate zone, start a workout on Apple Watch, and HeartOxy guides you from there. Most people are training in under a minute.

Yes. HeartOxy displays your heart rate on a live chart throughout your workout so you can see exactly how your heart rate responds in real time.

Yes. HeartOxy provides real-time haptic alerts whenever your heart rate moves outside your selected training zone, helping you stay focused on your workout instead of constantly checking your wrist.

By the time you notice you're outside your zone and look down at your Apple Watch, the moment has passed. HeartOxy alerts you immediately, so you can adjust without interrupting your session or losing focus.

Yes. Choose how often HeartOxy updates your heart rate during workouts — from every second for the fastest feedback to longer intervals that help extend battery life during longer sessions.

Apple Watch uses optical photoplethysmography (PPG) sensors to measure heart rate. Scientific studies comparing Apple Watch readings with ECG reference measurements have reported correlations of approximately 0.96 in general use and approaching 0.99 during exercise making it well-suited for zone training.

Heart rate zones are ranges that represent different levels of workout intensity. Staying within a zone helps you control how hard you're training — from light effort to high intensity.

HeartOxy lets you set your own zones and gives you real-time feedback and alerts during workouts so you always know when to push and when to ease off.

Heart rate zone training ensures workouts are performed at the correct intensity for your specific goals whether that's endurance building, fat burning or peak performance improvement.

HeartOxy automatically calculates personalised heart-rate zones using your age, resting heart rate (RHR) and heart rate variability (HRV), giving you training zones that better reflect your current fitness. It uses established training formulas rather than a one-size-fits-all estimate.

HeartOxy displays your current heart rate on a live chart, shows your active training zone in real time, and alerts you immediately when you move outside your selected range. You can stay focused on your workout instead of constantly checking your wrist.

Heart rate zones let you set an upper limit for your effort. HeartOxy alerts you on your wrist the instant your heart rate crosses above your selected zone so you can ease off before you overdo it.

Your Apple Watch records heart rate throughout the day. HeartOxy is designed for workouts where it provides real-time zone feedback and alerts.

Outside of workouts, it uses your recent data to give you a daily readiness view — helping you decide how hard to train.

Daily Readiness combines your resting heart rate (RHR), heart rate variability (HRV) and recent activity to estimate how ready your body is for today's workout, helping you decide whether to push harder or recover.

Based on your Daily Readiness status, HeartOxy suggests training one or two heart-rate-zone tiers down on days your body needs it — for example, suggesting Aerobic instead of Anaerobic on a strained day.

It never suggests training in a higher zone than usual and it never suggests a tier-down if you're already in your lowest zone.

Yes. Every workout is automatically saved so you can review your workouts, compare sessions and track your progress over time.

Yes. HeartOxy lets you export your workout history as a CSV file to analyse in spreadsheet software or share with your coach or training partners.

No. HeartOxy is available as a one-time purchase. Once unlocked, all premium features are yours without an ongoing monthly subscription.

SpO₂ measurements are taken automatically by Apple Watch and updated to HeartOxy.

To refresh or update the reading in HeartOxy, you can manually trigger a new measurement using the Blood Oxygen app on Apple Watch:

1. Open the Blood Oxygen app on Apple Watch
2. Start a new SpO₂ measurement
3. The updated reading will sync to HeartOxy

Alternatively, you can disable the feedback notification: Settings → Zone Feedback → Advanced → Below Zone Limit, then turn off the Below Zone Limit feedback option.

** Apple Watch (Series 6 and later, Ultra) takes random measurements of blood oxygen (SpO₂) levels automatically during sleep. However, you can obtain a measurement by using the Blood Oxygen app. It takes 15 seconds of steady, flat-wristed holding to get a reading.

Important Limitations: SpO₂ features are currently disabled on new Apple Watches sold in the USA due to a patent lawsuit, though they remain active on devices sold elsewhere and older US models.

If your heart rate or SpO₂ readings remain outside zones such as Below Zone Limit (HR), Above Zone Limit (HR), or Below SpO₂ Low, HeartOxy may trigger repeated intensity alerts every 10 seconds.

To reduce repeated notifications:

1. Open Settings
2. Go to Zone Feedback
3. Select Advanced
4. Turn off Repeat Zone Alerts

This will prevent repeated alerts every 10 seconds while readings remain outside the configured zones. Alerts will default to every 60 seconds instead.

No. HeartOxy is designed for wellness and fitness purposes only. It is not a medical device, not FDA-approved and not a substitute for professional medical advice. Consult a healthcare provider before starting any new exercise programme.