What is OpenID?

Hi
For sure there are natural variations in HRV during the day, but at least some of these are related to the time relative to when you were asleep. So in general the measurement you make will relate to how well you have recovered during that sleep, even if the hours are not regular every day. The shift patterns (I used to work 12hr shifts years ago) do represent a potential additional source of stress, from which you need to recover.
So if you do the ithlete test just after you wake up, and before eating or drinking (especially coffee / tea) then ithlete measurements should still be valuable to you.
If you do decide to go ahead & try it, feel free to share your findings on the Forum for all to see.

Good question!

The research science identifies two forms of overtraining :
1. Sympathetic overtraining - this is when your morning HR can be higher than normal, and for which reduced HRV gives an early warning
2. Parasympathetic overtraining - this is when your morning HR is significantly lower than normal, and can be an indicator of real fatigue, often as a progression from the first form

ithlete identifies both kinds and gives you amber and red warnings to tell you to take it easy when appropriate, so that the first form does not become the second.
My personal experience is that I can get the second form if I either ignore the amber ithlete warning and continue to train hard without sufficient recovery, or the day after a very hard endurance event.

Hi Dan

It seems artificial to wake up at 7am just to take the reading, rather than when you wake up naturally, hopefully feeling refreshed.

So I would tend to say do the reading when you wake up. Also, take a look at the post I put up yesterday about my hangover experience last weekend. That reinforces the idea that the ithlete reading will tell you when you are sufficiently recovered, so you might also consider doing a reading when you first wake up during your shift pattern, then also using that reading to help decide whether to try & sleep a little longer.

Does that make sense? Sorry I can't be fully clear on this one as there's not any research on HRV and shift patterns that I've come across.

That's really good input on HRV patterns and shift work - thanks. It does sound like the sudden drop in HR due to your unusually good rest is causing ithlete to indicate an abnormal value, sometimes indicative of parasympathetic overtraining. I think a way to tell for sure would be to walk around for a few minutes to get your system going out of its deep rest state and then repeat the measurement.
If you are fine, as we suspect, then your resting HR will have increased a bit into the normal range due to some adrenaline production. You can then safely delete the earlier reading on the Edit screen.
If on the other hand you were really in a state of overtraining (parasympathetic is the worst kind!) then your hormones would be exhausted and your resting HR would stay really low. Then the red indication would continue.
Have a great run!