Simple HRV

Most HRV (Heart Rate Variability) apps are overly complicated. This one simply measures RMSSD (root mean square of successive differences), the most important and widely used metric, and presents the data in a simple, easy to understand fashion. Warning: This app is only intended for educational and informational purposes only and is NOT intended for the diagnosis, cure, mitigation, prevention, or treatment of any disease or medical condition. # Features * Measures RMSSD in a 5 minute test, with time remaining display * Vibration alert signals the test completion * Real-time heart rate display (average HR shown at the end of the test) * Minimum, average, and maximum beat interval [ms] display * Beat interval distribution graph display. This can be used to check the quality of the measurement. Assuming you do not have any heart abnormalities, the beat interval distribution graph at the end of the test should ideally be a bell curve normal distribution shape. If it is not, it may indicate that you moved during the test or were mentally interrupted or stressed suddenly during the test. In these cases, you should repeat the test. # FULL Version Features * Configurable measurement duration * Real time update of min, average, and max beat interval display during the test * Real time update of beat interval distribution graph during the test * Historical plot of RMSSD (white points and lines) (up to 60 days, assuming one test per day) * 7 day moving average trend plot of RMSSD (green line) * Saves the HRV result to the activity session record in Garmin Connect. (The activity is saved as a "Meditation" activity) # Instructions 1. Pick a time of day when you are most free from physical and mental stressors. (Ideally you should do the test at the same time of the day each time to be able to interpret historical trends. For most people this is just after you wake up in the morning, before eating, exercise, checking your phone, etc.) 2. Ensure that your watch is worn snugly over your wrist. 3. In a seated restful position, start the app and press the [Start] button. 4. Rest and breathe normally until the end of the test, signaled by a vibration from the watch. 5. View the results. 6. In the FULL version, press the [DOWN] button (or on touchscreen models, tap the screen) to see the historical trend graph. 7. In the FULL version, when viewing the historical trend graph, press the [UP] button (or on touchscreen models, tap the screen) to return to the initial test screen. 8. You can press the [START] button to repeat the test. # NOTES 1. HRV varies depending on multiple factors including age, stress, respiration, physical fitness, heredity etc. As physical fitness is improved, HRV tends to increase. Low HRV can indicate poor vagal tone, meaning that the body is less adaptable to physical and mental stressors that it may encounter. 2. For an explanation on why the first thing in the morning is the best time to do the measurement, see: https://medium.com/@marco_alt/the-ultimate-guide-to-heart-rate-variability-hrv-part-1-70a0a392fff4 3. For an excellent description on interpreting the results, see: https://medium.com/@marco_alt/the-ultimate-guide-to-heart-rate-variability-hrv-part-2-323a38213fbc and also: https://medium.com/@marco_alt/the-ultimate-guide-to-heart-rate-variability-hrv-part-3-5fe902f3d2b3 # Payment Please make sure the free version works before attempting to buy the full version. For the FULL version, use this link to pay US$1.50 via Stripe (no account required; credit card, Apple Pay, Google Pay accepted). https://buy.stripe.com/dR64hVbIo3cxaIM4ju Alternative payment via Paypal: https://www.paypal.com/paypalme/trudelta/1.50USD

Version 0.8.1 Added support for the Forerunner 70 and 170. Version 0.8.0 Updated SDK. Added diagnostics. Version 0.7.3 Added support for the D2 Mach 2. Version 0.7.2 Added support for Venu 4 models. Version 0.7.1 Added support for the Fenix 8 Pro. Version 0.7.0 Attempt to fix crash problems. Added support for the Venu X1. Version 0.6.0 FULL Version only change: Prevented crash on startup on some models. Added setting to enable/disable saving of HRV results to Garmin Connect. Changed activity type for the Garmin Connect record to Generic Sport. Version 0.5.0 FULL Version only change: Saves HRV result to the activity session record in Garmin Connect. Version 0.2.6 Added support for Forerunner 570/970 models. Version 0.2.5 Added support for the Vivoactive 6. Version 0.2.4 Added support for the Descent G2. Version 0.2.3 Added support for the Approach S50/S44. Version 0.2.2 Added support for the Instinct 3 models. Version 0.2.1 Added support for the Enduro 3 and Fenix 8 series. Version 0.2.0 Attempt to fix crash occuring on some models. Version 0.1.7 Added support for Forerunner 165 models. Version 0.1.6 Added support for the Descent Mk3 43mm models. Version 0.1.5 Added support for Fenix 7 Pro Solar. Version 0.1.4 Added support for the Descent Mk3 model. Version 0.1.3 Added support for Fenix 7X Pro Solar. Version 0.1.2 Added support for Vivoactive 5. Version 0.1.1 Added support for Venu 3 series. Version 0.1.0 Adjusted layout for Instinct series.