Whether you’re training for heart coherence, trying to manage stress, or you’re just a data nerd who likes seeing stats, heart tracking can help you get a look at what’s happening under the hood while you breathe.
Quick Summary
Getting Connected: You need a Bluetooth heart monitor (chest straps like the Polar H10 are best). Ensure it is worn correctly. Read Setup Guide
The Science: I track Heart Rate Variability (HRV). By breathing rhythmically, you can achieve Coherence—a state where your heart rate accelerates and decelerates in a smooth, sine-wave pattern. Read About HRV & Coherence
The Charts:
- Live: You see Heart Rate, HRV, a Coherence “Speedometer” Gauge, a real-time Score (Good/OK/Poor), and Frequency Power (PSD).
- Post-Session: You get full timeline charts for HR, HRV, Frequency, and Score, plus an interactive PSD chart with a time slider. Learn How to Use
Compatibility: The app needs a device that transmit accurate R-R intervals. Dedicated heart monitors like the Polar H7, H9, H10 work well. Whereas “smart” watches/wearables like the Apple Watch, Whoop, Fitbit, Oura, etc don’t work because manufacturers don’t expose that data in order to lock you into their ecosystem. See Device List
Tech & Setup: Getting Connected
To use these features, you need external hardware. Specifically, a standard Bluetooth Heart Rate Monitor.
Supported vs. Unsupported
To measure Coherence and HRV accurately, I need the device to send R-R intervals (the exact timing between individual heartbeats), not just an average heart rate per minute.
- My Recommendation: The Polar H10 is the gold standard for accuracy. The Polar H9 is also great and more affordable.
- Smart Watches: Generally, stuff like the Apple Watch, Fitbit, and Whoop won’t work for live biofeedback here. They don’t broadcast R-R intervals via open Bluetooth channels.
Jump to the detailed breakdown of supported devices and my recommendations in the Appendix.
Troubleshooting Connection Issues
If you can’t get it to connect, run through this checklist:
- Permissions: Make sure you gave Paced Breathing permission to access Bluetooth (and Location on some Android versions) in your phone settings.
- Is it On? Most chest straps (like Polar) don’t have lights or buttons. They turn on automatically when you snap them onto the strap and wear them.
- Conductivity (The Water Trick):
- Chest Straps (Polar/Garmin): The sensor needs moisture to detect electricity. Your skin should be moist enough but sometimes (especially in dryer climates) it’s not. Put a tiny bit of water on your fingers and run them along the rubber electrodes on the strap before putting it on. This fixes connection issues 90% of the time.
- Armbands (Scosche): Make sure the band is tight and on your bicep (not the forearm). Try not to move your arm around too much.
- Battery: This is the most common issue. If a Polar strap is dead, it won’t warn you. Try a fresh battery.
Battery Life Tip
Since some monitors (like Polar) don’t have an “Off” button, they can drain if you leave the pod attached to the wet strap.
- Tip: When you’re done, unbutton one of the monitor connections from the strap. This breaks the circuit and makes sure it actually powers down.
Understanding the Data: HRV & Coherence
You’ve connected the monitor, but what are you actually looking at?
What is HRV?
Heart Rate Variability (HRV) is the fluctuation in time between heartbeats. Contrary to popular belief, a healthy heart doesn’t beat like a metronome. It speeds up and slows down based on what your nervous system is doing. Higher variability is generally a sign of a flexible, resilient nervous system.
How Breathing Impacts It
When you inhale, your heart rate generally speeds up. When you exhale, it slows down. This is called Respiratory Sinus Arrhythmia (RSA). By controlling your breath with the app, you’re manually controlling your heart rate.
What is Coherence?
Coherence happens when your breathing rhythm aligns perfectly with your heart rate changes. Instead of your heart rate looking like a jagged mountain range on a graph, it starts to look like a smooth, rolling ocean wave (a sine wave).
The Scoring System
I included a Coherence Score so you can see how “in the zone” you are. It ranges from 0 to 16.
- 0.0 – 3.0 (Poor): The heart rhythm is chaotic or not aligned with the breath.
- 3.0 – 5.0 (OK): You’re getting into the groove.
- 5.0+ (Good): High coherence. You’ve hit a resonant state.
The “Power” Charts (Advanced)
For the data geeks, I added a Power Spectral Density (PSD) view. Think of your HRV like a song. A “Fourier Transform” breaks that song down into its bass, mid, and treble frequencies.
- The chart shows exactly which frequencies are at play in your heart rate.
- In a state of high coherence, you’ll see a massive spike in one specific frequency (usually around 0.1 Hz), showing that all your energy is focused on that rhythm.
How to Use Paced Breathing with a Monitor
1. Connecting & Starting
- Put on your heart monitor (don’t forget to wet the sensors!).
- In the app, tap the Heart Icon at the bottom.
- Toggle the switch to Enable.
- Tap on your monitor name when it pops up.
- Optional: You can press the (i) icon to verify the data stream.
- Tap DONE.
- Note: You can test the connection for free, but saving session data and viewing advanced charts requires a PacedBreathing+ subscription.
- Start your session.
2. During the Session (Live Feedback)
While you’re breathing, you can swipe left/right on the visualization area or tap the heart tabs to cycle through different views:
- HR & HRV Charts: Simple line graphs.
- Coherence Gauge: This looks like a speedometer. It shows the frequency of your HRV in real-time. Try to keep the needle steady!
- Score Chart: A graph showing your Coherence Score rising and falling. The background is colored to show you the “Poor,” “OK,” and “Good” zones.
- Frequency Power (PSD): A bar chart showing the dominant frequencies right now.
XXX: ADD IMAGE HERE OF LIVE SESSION SHOWING THE SPEEDOMETER GAUGE AND SCORE CHART
3. After the Session (Review)
Once you finish, you get a full summary.
- Timeline Charts: Since the session is over, I replace the “Speedometer” with a frequency chart showing your stability over the whole session.
- Coherence Score: See how much time you spent in the Good vs. Poor zones.
- Interactive PSD: The Frequency Power chart now has a slider. You can drag it to see how your frequency power spectrum changed at any specific moment during the session.
XXX: ADD IMAGE HERE OF POST-SESSION REVIEW SCREEN WITH PSD SLIDER
4. Tracking Progress
Go to the side menu > My Progress. Here you can view aggregate stats to see if your average coherence score is improving over time.
How to Use This Data in Your Practice
You have the data, but how does it help you breathe better?
- Find Your Resonance: Everyone has a unique breathing rate where their coherence is highest (usually between 5 and 6 breaths per minute). Use the Coherence Score to test different settings. If you score higher at 5.5 breaths per minute than 6.0, that might be your “Resonant Frequency.”
- Instant Feedback: If you see your Score dropping into the “Poor” zone during a session, check your focus. Are you thinking about your to-do list? Are you tensing your muscles? Relax and refocus on the audio cues to bring the score back up.
- Motivation: Seeing the “Good” zone fill up on the chart is just a nice way to gamify it and keep your streak going.
Appendix: Device Compatibility List
Supported Trackers
The app is compatible with almost any heart rate monitor that accurately measures R-R intervals and uses Bluetooth 4.0+ (or ANT+ on Android).
Recommended:
- Polar (chest straps)
- H9: current entry-level model. Single connection, no memory. Works well with Paced Breathing and it’s cheaper (Amazon) — This is my main top recommendation
- H10: current flagship model. Can connect to 2 devices, save data onboard, and maintains a lock on your heart a bit better than H9 (Amazon)
- H7: discontinued model, but it still works well if you happen to own one already.
- Garmin (chest straps)
- Scosche (arm bands)
- Rhythm+ 2.0: current model. (Amazon)
- Rhythm 24: discontinued model, but still works if you happen to own one.
How to Choose: Chest Strap vs. Armband?
I get asked this a lot. Since smartwatches don’t work, you’re basically choosing between a chest strap (like Polar/Garmin) or an optical armband (like Scosche).
Here is my take:
1. Chest Straps (Polar H10, Garmin HRM-Dual)
- The Good: These use electrical signals (ECG), which is the most accurate way to measure HRV. They rarely lose connection once you have a good seal. The Polar H10 is basically the industry standard for this stuff.
- The Bad: They can be a bit uncomfortable. You have to wet the rubber sensors before putting it on, and it feels a bit like wearing a tight belt around your ribs.
2. Armbands (Scosche Rhythm)
- The Good: Way easier to put on (velcro on the bicep) and generally more comfortable.
- The Bad: They use optical sensors (lights), similar to a smartwatch. While Scosche is pretty good, optical sensors can sometimes struggle to catch the exact millisecond timing needed for HRV if you move your arm around too much.
My Verdict:
- If you want the best possible data: get the Polar H10.
- If you won’t use it for other things or you want to save a buck: get the Polar H9.
- If you dislike the strap, but wear sports bras: try the Garmin HRM Fit.
- If you really dislike chest straps: get the Scosche Rhythm+ 2.0.
Unsupported Trackers
These devices are generally unsupported, usually because the manufacturers do not allow third-party apps to access real-time R-R interval data.
Smart Watches (Unsupported):
- Apple Watch
- Whoop devices
- Fitbit devices
- Oura Ring
- Motiv Ring
- Garmin Watches (The watches themselves usually don’t broadcast R-R, though their chest straps do).
Other Unsupported Sensors:
- Wahoo: BLUEHR, TICKR FIT Heart Rate Armband
- Polar: OH1 Armband, Verity Sense
- UnderArmour: UA Heart Rate
- TomTom: BLE HRM
- Mio: ALPHA
- Biostrap
- Generic/Cheap Trackers: Avoid the knock-off straps sold on Alibaba or Amazon; they often fake the R-R signal or only report average Heart Rate. You get what you pay for!
Paced Breathing 