Eric Topol

are giving people information that your heart rate variability is bad, your stress is up.

I know a lot of people using the rings and they say they're constantly in stress because it's for heart rate variability.

Well, I don't know if that's really true, but that's, of course, that kind of output they get.

It's using a measurement.

with a lot of uncertainty, giving people health advice.

I think we'd like to have more vagal tone.

Maybe that's why you take cold showers, but a good way of measuring it.

And I would just submit that HRV, you don't want to hang your hat on that because there's a lot of uncertainties, right?

You know, one of the things that I like to look at, and I'm interested in your opinion, when you do exercise, you get your heart rate really jacked up.

And how fast do you recover?

To me, that's more useful because if it takes you a long time to get back to your basal heart rate, that's not a very good sign.

of your autonomic nervous system functionality.

It's qualitative, and you'll see maybe some outputs about that, but that to me is a pretty good indicator of fitness and functionality of the autonomic nervous system.

I don't know if you think that's true.

Because the VO2 max that you get out of a smartwatch is,

is very inaccurate and it's from walking.

You know, that's not the same as going to a physiologic lab and getting a tight fit mask and getting the real deal.

And I don't even know if you want to go bother with that.

But yeah, that's another thing that is being used a lot.

Not that that's connected so much with the vagal nerve per se, but these are misleading miscues that a lot of people are getting regarding their autonomic nervous system functions.