Know when to push and when to ease off.
Heart rate zone training for Apple Watch.
Guided by daily readiness and real-time zone feedback.
Requires Apple Watch Series 4 or later
Continuous Tracking
Track your heart rate continuously using Apple Watch's advanced sensors — during a run, a morning walk, a rehab session or any activity where knowing matters.
No noise. No distractions. Just consistent tracking while you move.
Start a session any time. No gym required.
Real-Time Monitoring
HeartOxy reads your live BPM continuously on your wrist throughout your session. No polling delay. No missed spikes. Just your real data, exactly when it matters.
While your Apple Watch tracks every beat on your wrist, your iPhone shows the full picture — a live chart of your heart rate and SpO₂, updating in real time. See the peaks, the dips, the pattern of your whole session. Zoom into the last 30 minutes or view up to 7 days at a glance.
And not just during your workout — HeartOxy helps you know how ready you are before you even start.
Built For
Runners, cyclists, HIIT — train in the right zone, every session. See the proof. Share it with your coach.
Recovery routines, daily walks, gentle workouts — start a session anytime you want to stay aware of your effort. Get alerted the moment you cross your threshold.
Seniors, stress monitoring, anyone who simply wants to know — stay active with confidence. A wrist tap tells you when to ease off.
What Our Users Say
"I use it every morning before I get out of bed. Knowing my heart rate before I stand up helps me plan how I ease into my day."
"I wanted a clearer read on my exertion during long walks. HeartOxy is the only app that gives me live numbers right on my wrist."
"I do zone 2 base-building runs. HeartOxy taps me the second I drift into zone 3. My aerobic fitness has never been better."
Reading Interval
Choose how often HeartOxy reads your heart rate: every second for maximum precision, every 3–5s for balanced tracking or every 10–20s to conserve battery. Match the precision to the activity.
Zone Training
HeartOxy uses six scientifically defined zones calculated from your age and Resting HR. Know exactly which zone you're in, every second of your session.
Zones aren't just for athletes. They're a simple way to see how hard your heart is working — from light and easy to peak effort.
Wrist Alerts
The moment your heart rate crosses a zone boundary, your Apple Watch taps your wrist. Below your limit. Within your zone. Above your zone. Above your limit. You'll feel the tap before you'd even think to check your watch. No phone. No glancing at a screen. Just instant feedback — so you can act.
After Every Session
After every session, HeartOxy shows your minimum, average and max heart rate plus a full breakdown of time in each zone. Export everything as CSV from your iPhone to analyze trends or share with your coach.
Fine tune what "Below Zone Limit", "Below Zone", "Above Zone", "Above Zone Limit", "Below SpO₂ Caution" or "Below SpO₂ Low" means for your body. Custom intensity sliders let you set exactly when you'll be alerted so alerts match your fitness level not a default.
Daily Readiness
Every day, HeartOxy compares your heart rate variability (HRV) and resting heart rate (RHR) against your personal 7-day baseline — continuously, from your Apple Watch and HealthKit data, not just during workouts. It's always visible on your History tab, right above your HRV/RHR insights, classifying your day as optimal, normal, elevated or strained.
Based on your readiness, HeartOxy suggests training one or two zone tiers down on days your body needs it — for example, Aerobic instead of Anaerobic on a strained day. It never suggests going up a tier, and never suggests a redundant tier down if you're already at your lowest zone.
Not noisy.
Not complicated.
Not incomplete.
Just continuous. Precise. Controlled.
HeartOxy gives you clarity in real time.
Support
Apple Watch measures your heart rate throughout the day and continuously during workouts.
HeartOxy builds on this by adding zone-based tracking and customizable alerts and gives you control over how frequently your heart rate is sampled during workouts — from every second to longer intervals — so you can choose the level of detail that suits your training.
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.
Zones are based on your personal heart rate profile, using your age and resting heart rate, and calculated with established methods like Tanaka and Karvonen — not guesswork or a simple one-size-fits-all estimate.
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 calculates your heart rate zones using your age and Resting heart rate (RHR), creating ranges tailored to your body — not a generic estimate.
It uses established methods like Tanaka and Karvonen, which are widely used to set personalised training zones based on your actual fitness profile.
This means your zones are grounded in real data, helping you train at the right intensity with confidence.
Start a workout on your Apple Watch and your heart rate will be measured continuously. HeartOxy builds on this by showing your current training zone in real time and alerting you the moment you move above or below your selected range.
This helps you stay in control of your workout intensity without needing to constantly check your screen.
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 compares your heart rate variability (HRV) and Resting heart rate (RHR) against your personal 7-day baseline. It runs continuously from your Apple Watch and HealthKit data — not just during workouts — and classifies each day as optimal, normal, elevated or strained. It's always visible on your History tab, above your HRV/RHR insights.
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.
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:
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:
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.
Yes. HeartOxy lets you export heart rate data as a CSV file which can be shared with healthcare professionals for informational discussions.