AMA #31: Heart rate variability (HRV), alcohol, sleep, and more

**Peter Attia** (0:11)
Hey, everyone, welcome to a sneak peek, Ask Me Anything, or AMA episode of the Drive podcast. I'm your host, Peter Attia. At the end of this short episode, I'll explain how you can access the AMA episodes in full, along with a ton of other membership benefits we've created. Or you can learn more now by going to peterattiamd.com forward slash subscribe. So without further delay, here's today's sneak peek of the Ask Me Anything episode.
Hey everyone, welcome to Ask Me Anything episode number 31 I'm joined once again by Bob Kaplan, although as you'll learn at the end of this episode, this will be the last time we're joined by Bob Kaplan, but let's not get ahead of ourselves. In today's episode, we talk about really two things in detail. One is HRV, heart rate variability. We've had so many questions on this subject for the past couple of years, and we've just been slowly kind of collecting questions until we thought we had enough to do kind of one of our thematic shows on it. And the second thing we talk about is ethanol, all things related to ethanol. So how does it affect HRV is really our segue, but then also what are the effects of alcohol on sleep? And we really go after mortality, probably where we spend most of our time, and we talk about it through the lens of all of the epidemiology, as most of you or may some of you know, there's a confusing body of literature out there that suggests that maybe some alcohol is good for you and no alcohol is not as good for you. And so we go really deep on this subject matter. So again, if you have any questions about alcohol or if you drink at all, and if you don't drink and you're wondering if you should be drinking, I think this episode will be very helpful for you. So one thing I wanna point out for this episode, this episode was just due to some limitations of timing when we recorded it. This was not recorded in video, so we will only be doing this in audio.
That might make the show notes a little more important, although we didn't really have a lot of content here that necessitated being able to see.
So I think you're gonna be fine listening to this in audio, but obviously the show notes will have any of the graphs and other images that we talk about. Now, if you're not a subscriber, of course you can get a sneak peek of this as usual, and then you'll have to obviously subscribe if you want to enjoy the full content. So without further delay, I hope you enjoy AMA number 31
Hey, Bob, how's it going today?

**Bob Kaplan** (2:32)
Going well, Peter. How are you?

**Peter Attia** (2:33)
It's good. It's a little unusual today. We're doing this a little bit on the old school tip. No video today. We're gonna have to be a little bit more descriptive in our terms since people can't watch our facial expressions, although that somehow provided any value.
We won't do any screen sharing.

**Bob Kaplan** (2:50)
I think we can manage.

**Peter Attia** (2:51)
What do you have in store for us today?

**Bob Kaplan** (2:54)
So I aggregated a whole bunch of questions around HRV, heart rate variability and alcohol. Many questions on both those topics.

**Peter Attia** (3:05)
I know this has been something you've been asking me about for a year. When are we gonna do one on HRV? When are we gonna do one on HRV? So I think the answer is now.

**Bob Kaplan** (3:13)
All right, we'll dive in.
First question seems relevant. What is HRV?

**Peter Attia** (3:20)
And it's funny, this is a tougher question to answer without an image, but I'll do my best. So as you pointed out a second ago, HRV stands for Heart Rate Variability. And that's a pretty descriptive term because what it measures is the variation in time between heartbeats, and that's measured in milliseconds. So a thousand milliseconds is one second. So if a person's heart is beating 60 times per minute, you might say, well, there's a thousand milliseconds between every beat, but it turns out that it's not really that way. You see, even if your heart is beating 60 times per minute or once per second, between the first beat and the second beat, it might be a thousand ten milliseconds.
And between that beat and the next beat, it might be 960 milliseconds. And between that beat and the beat thereafter, it might be 1027 milliseconds. When you start looking at this thing at the level of thousandths of a second, you realize that there is actually some variability. If anybody has ever seen an EKG, which I'm sure everybody has seen, but maybe you haven't thought so much about what all the little squiggly lines mean, without going into the details of what the P wave and the QRS and T waves mean, I think most people will recognize that there is a very big spike for each of those beats, and that's actually the R spike. If you now measure the distance between the Rs, we call that the RR interval, and you take the root mean square of the successive differences between the heartbeats, so that means you calculate the time difference between each RR interval.