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Health Snapshot RMSSD calculation does not match fit file 955 12.23

Hi all,

I have 5yrs of HRV fit data that I have been analysing with Kubios - so I have at least some idea. I did a health snapshot on my new 955 it gave me a RMSSD of 31ms. When I downloaded the Health Snapshot fit file on garmin connect and ran i through Kubios it has a RMSSD of 24ms. For me (62yo male) this is the difference between going hard and easing off so I'd like to know what's going on here before I rely on the 955 data.

Does anyone know how Garmin calculates RMSSD? is it different from industry standard?

thanks,

Matthew

0 Dmitriy9265 over 3 years ago

I faced the same problem, compared it with the HR V Expert application in a 2-minute measurement, took measurements with the POLAR H10 chest heart rate monitor, the RMSSD in GARMIN only coincided with the HRV Expert a couple of times, in other cases GARMIN showed RMSSD much higher or lower, as well as measuring the night HRV in comparison with the Polar Vantage V mainly slightly lower, or much lower than I was during the entire time of monitoring HRV during sleep, even after a hard workout, and last night I did not measure HRV at all. I just bought this watch and also want to understand what is the reason for incorrect HRV and RMSSD measurements, I used to track recovery by night recovery on Polar, which almost always coincided with my well-being, maybe this is due to the old firmware version 11.12, I am not in a hurry to update to the latest version because I see that many are experiencing problems with the training effect.

0 MattD110td5x over 3 years ago in reply to Dmitriy9265

Hi Dmitriy, I can kinda understand that a chest strap could give different results to wrist based optical pulse measurements. For sure the chest strap is going to be more accurate.

The problem I have is much simpler, For a given FIT file the Garmin calculated RMSSD is different to the actual RMSSD calculated by industry standard Kubios. As a check I exported the values to excel and manually calculated RMSSD, the result and it agrees with Kubios.

- matthew

0 Dmitriy9265 over 3 years ago in reply to MattD110td5x

Hello MattD110td5x, yes I understand what you mean and agree with you, it's some kind of problem in the Garmin calculation, yesterday I installed two apps on the watch from Connect IQ, for measuring HRV SDNN and nervous system balance, and compared the app data at the same time with the HRV measurement using a chest strap, the difference between the watch and the belt was about no more than 3ms in the hrv measurement and about the same sdnn, even the nervous system balance measurement was very close with a difference of about 0.10-0.15, which I consider to be a fairly accurate change for the optical heart rate monitor, in one of the measurements I tried to specifically move the hand on which the watch was, but still it didn’t work out to get a large HRV error much more, this affected SDNN, which is logical in principle. Also this morning, the HRV readings of the Garmin watch are 45 ms average and 75 ms maximum, while on the polar vantage V watch the average HRV is 83 ms. it matches my feelings. Also yesterday I tried again to take a quick snapshot of health on a Garmin watch and each time I got different results, in one rmssd was very close to the chest strap no more than 1 ms

0 Dmitriy9265 over 3 years ago in reply to Dmitriy9265

sorry for my english, it's very bad, that's why i use a translator

0 Dmitriy9265 over 3 years ago in reply to Dmitriy9265

Приложения, которые я использовал от connect IQ HRV longger и Fb3 Monitor + HRV

0 Dmitriy9265 over 3 years ago in reply to Dmitriy9265

Диаграммы ВСР POLAR Vantage V и GARMIN night, диаграммы сердечного ритма одинаковы.