HRV Recording Methodology: Stabilization

Smart phone app’s and other field tools have made HRV data collection relatively simple and affordable for coaches, athletes and recreational lifters. However, the shortened recording methodology utilized by these devices requires validation. Standardized guidelines recommend that short-term (i.e., 5-min) HRV be collected under physiologically stable conditions (Task Force). Most HRV papers will allow for 5 minutes or greater of supine rest prior to HRV recording to allow for stabilization. However, this 5+ minute pre-recording period is not practical for daily monitoring. A 1 – 2 minute HRV recording period with a very minimal stabilization period used by many app’s is still too long for some individuals to comply with daily measures.

The issue of “stabilization” was the topic of our latest research project that we just presented at the ACSM Annual Meeting in Orlando this past weekend. We looked at the time-course for stabilization of HRV across 5-min ECG segments (e.g., 0-5 min, 1-6 min, 2-7 min, 3-8 min, etc.)  in 12 endurance athletes (6 female) and 12 non-athletes (6 female). We included lnHFnu, lnLFnu, and lnRMSSD.

The figures from the poster are displayed below (Athletes on left)

Stab Poster title

stability figures

 

The full manuscript for this project (with a different methodological approach) is currently in review so I will not get into too much depth on the discussion of the results. However, it is quite clear that lnRMSSD demonstrates the most and earliest stability of the 3 HRV parameters. Therefore, for lnRMSSD assessment, a minimal stabilization period is likely a non-issue. When including spectral measures (e.g., HF, LF), a longer period for stabilization may be required, though lnHFnu was relatively stable in the athletic group in the current sample.

 

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About hrvtraining

Researcher and Professor. Former coach.
This entry was posted in Heart Rate Variability and tagged , , , , . Bookmark the permalink.

One Response to HRV Recording Methodology: Stabilization

  1. Jim says:

    Very interesting. I have noticed this myself. RMSSD is mostly pretty stable over the recording period. I have used Sweetbeat, HRV Logger and Smartbeat, all of which display the RMSSD values during recording. Smartbeat and HRV Logger in particular provide lots of exportable data – so the consistency of different values can easily be validated. I have however noticed that HF and LF jump all over the place, often going from high to low or vice versa over the recording period. Having read up a bit on these values, I am unsure what can be concluded from them, it seems the old idea that LF represents stress and HF the reverse is no longer held to be valid, hence I wonder if there is really anything to the LF:HF ratio?

    My preferred daily app is now iThlete. Its simple, straightforward and consistent, insofar as readings rise and fall in multi day waves, presumably as the underlying health/fitness varies. It does not appear to use LF or HF. If I am honest, I will also add that it gives me a higher HRV score than Sweetbeat, which is gratifying!

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