Whether you are interested in measures of resting physiology and chronic stress, biofeedback exercises, would like to design your own research study or to embed our camera-based technology in your product, we can help

Assessment of resting physiology
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For individuals and teams. Check out HRV4Training to learn more

Biofeedback and deep breathing
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For individuals and coaching. Check out HRV4Biofeedback to learn more

​Research projects and protocols
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Camera Heart Rate Variability apps for iOS and Android

RESEARCH AND AEROBIC THRESHOLD
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Heart Rate Variability Logger for Android and iOS. Learn more in the FAQ page

Validated technology

The camera-based PPG and HRV analysis employed in our solutions has been validated [1] with respect to the clinical standard (electrocardiography, or ECG) as well as consumer chest straps (Polar H7). You can find the full paper at this link.

Here you can find an example where we show a comparison of peaks detected from a full ECG (Cosmed, reference system) and PPG data acquired using our technology, showing how the peaks are perfectly aligned
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[1] 2017. D.J. Plews, B. Scott, M. Altini, M. Wood, A.E. Kilding and P.B. Laursen, "Comparison of heart rate variability recording with smart phone photoplethysmographic, Polar H7 chest strap and electrocardiogram methods", accepted for publication in the International Journal of Sports Physiology and Performance.

Frequently Asked Questions

WHAT'S THE DIFFERENCE BETWEEN THE APPS?

We currently support two consumer products and two research apps. The consumer products are solutions that address a specific problem:

• HRV4Training: measurement of resting physiology first thing in the morning, to determine how you are responding to training and lifestyle stressors
• HRV4Biofeedback: deep breathing exercises to strengthen the parasympathetic system and improve self-regulation

​Both apps can be used with the phone camera or using external Bluetooth sensors. More details on both apps can be found below

We also support two research apps which do not provide any interpretation but allow for more flexibility during data collection and export of RR intervals. These apps are used mostly for research studies or self-experimentation:

• HRV Logger: research app that requires a Bluetooth sensor
• Camera HRV: camera based research app

In addition, the HRV Logger is the only app on the market able to provide real-time DFA alpha 1, a non-linear HRV feature that can be used for exercise intensity estimation and to determine the aerobic threshold

​Please see below for more details

Resting physiology or biofeedback?

HRV analysis can be used for various applications. What we do with HRV4Training is to quantify baseline physiological stress (what we could call "chronic" stress), and how this changes in response to training and lifestyle over periods of weeks or longer. To quantify baseline physiological stress, measurements need to be taken in a very precise moment, which is first thing in the morning, so that we can avoid the effect of confounding factors. You can find a few examples here

By capturing changes in resting physiology, we can provide useful feedback that helps individuals to make meaningful adjustments to better balance training and lifestyle. This is particularly relevant as we all respond differently even to the same stressors depending on various aspects (how novel is the stressor, how much of that stressor we are used to take, what other stressors are present), hence only by measuring our individual response we can figure out if it's all proceeding according to our plans or not

What about HRV biofeedback then? 

HRV Biofeedback is a technique that we use to improve self-regulation, and also strengthen the parasympathetic system. While our morning measurements should be done while resting and breathing naturally, during biofeedback we use deep breathing to elicit higher parasympathetic activity

You can see your biofeedback session the same way you see your other training sessions, this is something you do so that in the longer term, there can be beneficial changes in health and performance. Biofeedback is just a positive stressor

Where do regular baseline HRV measurements and Biofeedback meet?

Normally we would recommend doing biofeedback exercises as an add on the regular morning measurement done with HRV4Training. Combining biofeedback with morning measurements taken with HRV4Training, you could see also potential changes in baseline chronic physiological stress as measured in a known context (first thing in the morning), as a result of your biofeedback sessions

How can I use hrv logger for aerobic threshold estimation?

In order to use the HRV Logger for aerobic threshold estimation, please do the following:

• Set artifact correction to “Workout” and feature computation window to “2 minutes” in the app Settings
• Link your chest strap, we highly recommend a Polar strap for this test
• Run or cycle. Either a rather constant easy effort or an easy progression are ideal for this kind of analysis. Short intervals or frequent changes in intensity should not be used for this test as at least 2 minutes of stable data are required
• Your aerobic threshold will be at alpha 1 = 0.75, as reported in the app’s HRV features and also in real-time.

You can learn more about this method, in this blog post and find the FAQ here

What phones are supported FOR THE CAMERA BASED MEASUREMENT?

Our camera-based technology works reliably on all iPhones from the 5 onwards. You can find instructions for the camera-based measurement here

HRV4Training and Camera Heart Rate Variability are also available on Android. While not all Android phones can be supported, the apps use special algorithms to determine if the phone is supported and report back to the user, so that only accurate data is collected

Have the apps been used in other research studies?

Yes, the apps have been used in many research studies over the years, leading to novel insights due to the ease of use and accuracy which enabled longitudinal data collection where it was not possible beforehand.

​Some examples are listed below [2] on the relation between the menstrual cycle and HRV, [3] on HRV-guided training and the associated improved performance, [4] measurements taken first thing in the morning or at the facilities in team sports, [5] training load and performance in swimmers. 

[2] Kokts-Porietis, R. L., Minichiello, N. R., & Doyle-Baker, P. K. (2019). The effect of the menstrual cycle on daily measures of heart rate variability in athletic women. Journal of Psychophysiology
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[3] Javaloyes, A., Sarabia, J. M., Lamberts, R. P., Plews, D., & Moya-Ramon, M. (2020). Training prescription guided by heart rate variability vs. block periodization in well-trained cyclists. The Journal of Strength & Conditioning Research, 34(6), 1511-1518

[4] Sherman, S. R., Holmes, C. J., Hornikel, B., MacDonald, H. V., Fedewa, M. V., & Esco, M. R. (2021). Heart-Rate Variability Recording Time and Performance in Collegiate Female Rowers. International Journal of Sports Physiology and Performance, 1(aop), 1-7

[5] Piatrikova, E., Willsmer, N. J., Altini, M., Jovanović, M., Mitchell, L. J., Gonzalez, J. T., ... & Williams, S. (2021). Monitoring the Heart Rate Variability Responses to Training Loads in Competitive Swimmers Using a Smartphone Application and the Banister Impulse-Response Model. International Journal of Sports Physiology and Performance, 1(aop), 1-9

Can I get the raw data?

Camera Heart Rate Variability and Heart Rate Variability Logger, our research tools, both provide RR intervals in csv files (as well as heart rate and HRV features).

​If you are interested in the raw PPG to be further processed for algorithm development, please reach out and we can discuss a custom solution

No Medical or health advice

​The apps are not intended to diagnose, treat, cure, or prevent any disease, illness, or health problem. the apps are not intended to provide health or medical related advice. if you (i) have any medical condition, (ii) are taking any medication, (iii) are pregnant, or (iv) have chest pain, joint pain, or shortness of breath, you agree to consult a physician before using the apps. If you experience any discomfort when using the apps, you agree to immediately discontinue use and consult a physician.