Blog post by Marco Altini Our validation paper comparing camera based acquisition, Polar H7 (chest strap) and electrocardiography (ECG) was accepted for publication in the International Journal of Sports Physiology and Performance. The paper is titled "Comparison of heart rate variability recording with smart phone photoplethysmographic, Polar H7 chest strap and electrocardiogram methods" and the main author is Daniel Plews, who I'd like to thank, together with all other co-authors (Ben Scott - who carried out the entire data collection, and also enjoyed participating in the study as shown below, as well as M. Wood, A.E. Kilding and Paul Laursen), for their work on this paper. In this study we had the luck to collect a wide range of rMSSD values, Ben himself provided us with his own ridiculously high HRV data (rMSSD ~300ms), something that triggered the need for a different way to handle artifacts and correct for ectopic beats, as the current standard used in clinical practice (discarding beats that are more than 20-25% apart) would overcorrect in case of such high HRV (these changes have been implemented in the app almost a year ago).
If you've been following this blog, we've shown plenty of samples already to validate the accuracy of the camera based measurement with respect to regular chest straps, for example here, here for iOS10, here for the iPhone 7+ and the double camera drama, and finally here where we compared many different PPG devices. However, this is the first time we show also ECG data, the gold standard (see a sample here). We think it's very important to go through peer reviewing as well and being clear and transparent on our work, and this paper is a good step forward. I'd like to take the opportunity to stress again that while validated, PPG measurements need to be taken in a certain way, as they are more prone to noise with respect to other methods. It's important to limit movement as much as possible, and in general to follow the simple steps we covered in this blog post. Note also that PPG doesn't work for everyone, for example low perfusion might cause trouble in detecting blood flow with this method, even though we haven't seen many of these cases. This being said, the app is typically pretty good at detecting when things go wrong and informing you. Make sure to obtain optimal signal quality when measuring and to practice using the practice mode under Menu / Resources in the app, if you have trouble obtaining optimal signal quality. Comments are closed.
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Marco Altini, founder of HRV4Training Blog Index The Ultimate Guide to HRV 1: Measurement setup 2: Interpreting your data 3: Case studies and practical examples How To 1. Intro to HRV 2. How to use HRV, the basics 3. HRV guided training 4. HRV and training load 5. HRV, strength & power 6. Overview in HRV4Training Pro 7. HRV in team sports HRV Measurements Best Practices 1. Context & Time of the Day 2. Duration 3. Paced breathing 4. Orthostatic Test 5. Slides HRV overview 6. Normal values and historical data 7. HRV features Data Analysis 1a. Acute Changes in HRV (individual level) 1b. Acute Changes in HRV (population level) 1c. Acute Changes in HRV & measurement consistency 1d. Acute Changes in HRV in endurance and power sports 2a. Interpreting HRV Trends 2b. HRV Baseline Trends & CV 3. Tags & Correlations 4. Ectopic beats & motion artifacts 5. HRV4Training Insights 6. HRV4Training & Sports Science 7. HRV & fitness / training load 8. HRV & performance 9. VO2max models 10. Repeated HRV measurements 11. VO2max and performance 12. HR, HRV and performance 13. Training intensity & performance 14. Publication: VO2max & running performance 15. Estimating running performance 16. Coefficient of Variation 17. More on CV and the big picture 18. Case study marathon training 19. Case study injury and lifestyle stress 20. HRV and menstrual cycle 21. Cardiac decoupling 22. FTP, lactate threshold, half and full marathon time estimates 23. Training Monotony Camera & Sensors 1. ECG vs Polar & Mio Alpha 2a. Camera vs Polar 2b. Camera vs Polar iOS10 2c. iPhone 7+ vs Polar 2d. Comparison of PPG sensors 3. Camera measurement guidelines 4. Validation paper 5. Android camera vs Chest strap 6. Scosche Rhythm24 7. Apple Watch 8. CorSense 9. Samsung Galaxy App Features 1. Features and Recovery Points 2. Daily advice 3. HRV4Training insights 4. Sleep tracking 5. Training load analysis 6a. Integration with Strava 6b. Integration with TrainingPeaks 6c. Integration with SportTracks 6d. Integration with Genetrainer 6e. Integration with Apple Health 6f. Integration with Todays Plan 7. Acute HRV changes by sport 8. Remote tags in HRV4T Coach 9. VO2max Estimation 10. Acute stressors analysis 11. Training Polarization 12. Lactate Threshold Estimation 13. Functional Threshold Power(FTP) Estimation for cyclists 14. Aerobic Endurance analysis 15. Intervals Analysis 16. Training Planning 17. Integration with Oura 18. Aerobic efficiency and cardiac decoupling Other 1. HRV normal values 2. HRV normalization by HR 3. HRV 101 |