So w- from that vantage point, uh, in that section of the guidelines, what, what do you think are the next steps with, within HRV research? How can the field advance, and how can we leverage this vast data being, being generated, uh, w- with the wearables without compromising the physiology and, and, you know, the state of trust within science, as Nisha's been pointing out?

Yeah.

Thanks, Jason.

I think that's a great question.

And you know, you're right.

It's almost all cross-sectional, and even the good prospective cohorts can't fully disentangle it, because low heart rate variability travels with all the same things that drive cardiovascular risk, right, in the first place: low physical activity, poor sleep, chronic stress, alcohol.

So- I don't think we can honestly say whether reduced heart rate variability is causing anything, or whether it's just a convenient measure of the same underlying process of all of these other things, right? The first thing I think, um, is to really think about the study design.