Improve breathing and reduce stress using Breathe Flow app on your Apple Watch

Breathe Flow App on Apple Watch

A new app, Breathe Flow, available from Vagus Health, provides deep insights into your breathing.

The app provides advice on how to improve breathing and reduce stress.

Related reading:

Breathe Flow App to improve breathing

The app is easy to use and requires you to perform a 30-second ECG test on your Apple Watch, Withings smartwatch, or Samsung Galaxy Watch to get started.

The app shows you your real breathing and teaches you to do controlled breathing with their unique ‘ideal breathing curve.’

The app works with numerous smartwatches

The new Breathe Flow app is available on both the Apple app store and Google Play Store for wearOS, and you can use it on Apple, Samsung, and Withings watches that include an ECG sensor. 

Apple Watch users need to use their ECG recording app on their watch and use the Breathe Flow app on their iPhones and keep it live to follow the instructions.

Samsung Galaxy Watch users need to download the Breathe Flow Wear OS app on the Play Store on their Watch. Use it to do the recordings. Keep BREATHE FLOW live on your phone.

Similarly, Withings ECG Watches can open the Withings “Health Mate” app on the phone. Keep BREATHE FLOW live. Record according to Withings instructions.

Importance of Vagus Nerve

It is widely known in the scientific community now that the vagus nerve is our most important nerve for immunity and health problems such as stress, anxiety, inflammation, and depression. 

The simple idea is that users can adjust their lifestyles by monitoring the vagus nerve to achieve better health and higher quality of life.

How to use Breathe Flow on your Apple Watch

Once you download the Breathe Flow app from Vagus Health on the App Store, you are ready to go.

Make sure that the new app is present on your Apple Watch before moving on to the steps below.

  1. Open the ECG app on your Apple Watch.Apple Watch ECG app
  2. Hold your finger on the crown.
  3. Inhale deep and calmly during the first 5 seconds with your finger on the crown.
  4. Once you complete the 30 seconds on the ECG app, open the Breathe Flow app on your iPhone.Breathe Flow app on iPhone
  5. You find the instructions to interpret your breathing curve in the Breathe Flow app.

Interpreting Sinus curves with Breathe Flow app

The first chart in the app you see is the Breathe Flow chart, which shows you how well you inhaled and exhaled during the ECG recording.

The Blue line on the chart signifies your breathing. When you inhale, the blue line moves upwards; similarly, when you exhale, it moves downwards.

The important callouts in the graph are the places where the blue line becomes blurred or changes color. This signifies non-smooth breathing.

When using the ECG app for Breathe Flow, make sure to practice diaphragmatic breathing as opposed to shallow breathing.

The rationale is that deep breathing makes the vagus nerve and the body’s autonomic, cardiac, and respiratory systems work best.

Your stomach should visibly move in and out during breathing.

Your goal is to get a smoother sine wave.Breathe Flow Metric on Apple Watch

When mindful of your breathing, the diaphragm movement and pulse changes synchronize, the vagus nerve is activated, and oxygenation becomes optimal.

Doing deep breathing work several times daily reduces your stress and anxiety and improves the vagus nerve’s ‘relax and healing’ capacity.

You see a detailed list of inferences from the app with the provision to ask questions directly on that screen.

Breathe Pulse Inferences

The following section below the Breathe Flow chart is the Breathe pulse inferences. You must answer a few simple Q&A to enable the Breathe Pulse calculations.

To get started, tap on the ‘Complete Q&A to enable Breathe Pulse’ on the Breathe Flow app on your iPhone.

BHI or Breathing Health Index Diamond Chart

The app provides a BHI (Breathing Health Index) score and shows the relationship between four major variables in a diamond chart. These variables are:

  1. Since the ECG test triggers an HRV calculation, your HRV score is available.
  2. BRE, or Breathing depth index is the next metric. This signifies how deep you are breathing. According to the app maker, when you breathe effectively, your BRE score should be greater than 50. When the depth index is higher, you are doing deeper and better breathing with large volumes in airflow. According to the app maker, w 
  3. RSS, or Respiratory sinus smoothness is an index for how smooth the breathing curve is during the test. The index value is between 0 – 100, where 100 is very smooth (good.)
  4. CSS or Cardiac sinus smoothness is the last metric on the diamond chart that shows how smoothly the heart rate varies up and during the ECG test.

On the Diamond chart provided in the app, your objective is to cover the diamond as much as possible.

In the example below, my BRE scores were a dismal 5 ( 0 – 100 scale), which dramatically minimizes the diamond chart coverage.Breathing Health Index on Apple Watch

This would mean I need to breathe slowly and deeply when doing the test next time.

As per the app, your average BHI or Breathing Health Index should be higher than 50.

We are not sure how the app accounts for age, sex, and other factors that can influence the aggregate score. The app integrates with Apple Health and brings over your name, date of birth, and gender info from your Apple Health settings automatically.

Overall, the Breathe Flow app from Vagus Health looks great and automatically provides some good insights about your breathing and stress management. Try the Box Breathing technique, and you will see good results.

We are unclear why this or any health app would require provisioning for Vagus NFT tokens. That part looks sketchy on the app; otherwise, it gives you a solid understanding of your basic respiratory health parameters and can help you train your breathing.

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Sudz Niel Kar
I am a technologist with years of experience with Apple and wearOS products, have a BS in Computer Science and an MBA specializing in emerging tech, and owned the popular site AppleToolBox. In my day job, I advise Fortune 500 companies with their digital transformation strategies and also consult with numerous digital health startups in an advisory capacity. I'm VERY interested in exploring the digital health and fitness-tech evolution and keeping a close eye on patents, FDA approvals, strategic partnerships, and developments happening in the wearables and digital health sector. When I'm not writing or presenting, I run with my Apple Watch Ultra or Samsung Galaxy Watch and closely monitor my HRV and other recovery metrics.


  1. Downloaded the breathe flow app and I ran the EKG app on iwatch and open breathe flow and it just gives me the graph and it shows Very Poor with BHI=0. Tried it 5 times with closing the EKG after running it and leaving the EKG open and running breathe flow.


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