Recent articles and updates [July 2024]
Recent articles and updates [July 2024]
heart rate variability, wearables, entrepreneurship, training talk and some ramblings
hi there 👋
I hope all is well.
Here is my newsletter including articles and updates from July 2024. I hope you’ll find it useful and I would like to take the opportunity to thank you for your support.
Please feel free to comment below or in the articles should you have any questions, and I will follow up soon.
Take care!
Heart rate variability (HRV) 🫀
What's the use of heart rate or HRV data? Heart rate and heart rate variability (HRV) data cannot unequivocally be translated into your recovery, stress, physical or mental strain, or anything else, really. Our physiology unfortunately is not so trivial that you can measure it and get a clear outcome measure the way it is often advertised. What’s the use then of heart rate and HRV data? Learn more, here.
What’s the best protocol for measuring heart rate variability (HRV)? To answer this question we need to remember what HRV is about and what our goal is when using HRV. HRV is our stress response, when measured at the right time. Measured at the right time means: at rest far from stressors. Why? Because measuring during or close to stressors turns any normal physiological response into something pathological. Keep reading, here.
Podcasts 🎙️
Earlier this year I spoke with Mikki Williden about heart rate, heart rate variability, stress and lifestyle. We discussed HRV, what it means, what affects it, how it is measured and the best conditions for doing so. We also talked about the impact diet can have on HRV and sex-related differences, whether or not these are clinically meaningful. We discussed also HRV Biofeedback and the impact of simple actions that we can take to improve our stress response and HRV. Finally we talk about wearables and the limitations (and benefits?) of tracking sleep.
You can find the episode, here.
Building 🛠️
Parasympathetic saturation in HRV4Training Pro. This is a little-known feature that can detect a situation in which HRV is suppressed but the interpretation should not be negative. If you are in a period of high training load and HRV is low, together with low heart rate, and therefore the correlation between HRV and the average RR interval length is small or negative, parasympathetic saturation is plausible. In the plot below, you would see the darker dots in the lower right corner (low HRV, low heart rate or high RR interval length), and a lower correlation e.g. 0.2 or lower. In this case, the suppression in HRV should not be interpreted negatively, as reported by Plews et al.: "the lack of correlation between the R-R interval and Ln rMSSD indicate that athletes are more likely to undergo parasympathetic saturation" (something you can learn more about, here).
Training talk 🏃🏻♂️🚴
What about lactate? Over the years, I have tested lactate a few times, using the typical incremental protocols, as well as spot checks after holding the intensity more or less constant on a ‘real-life endurance run’ (i.e. outside, in the conditions I normally train, near what I would consider upper-end Z2). I’ve added some notes about lactate towards the end of my blog about heart rate zones and training intensity, which you can find here.
Training log. As the name says, this is simply my training diary for this year.
Ramblings and rants 🤌
A few tweets that haven’t made it into a blog post just yet.
Please note that my X / Twitter account is now private, so you will have to follow me there as well to see the tweets below (sorry about that, it was a necessary move for my mental health):
Outside of rest conditions, there is no use for PPG data in the context of HRV analysis. Check out the latest research.
In this study of sleep deprivation and HRV, no change in heart rate or HRV measured while lying down was visible during three nights of reduced sleep (3 hours per night) however, HRV measured while standing resulted in a suppression. Use good protocols.
"Sleep heart rate variability assists the automatic prediction of long-term cardiovascular outcomes". But can it, really? Let’s look at the data.
19 years with Ale. Also this.
ChatGPT knows its sources, it seems.
That’s a wrap for this month.
Thank you for reading, and see you next month!
Recent newsletters:
Marco holds a PhD cum laude in applied machine learning, a M.Sc. cum laude in computer science engineering, and a M.Sc. cum laude in human movement sciences and high-performance coaching.
He has published more than 50 papers and patents at the intersection between physiology, health, technology, and human performance.
He is co-founder of HRV4Training, advisor at Oura, guest lecturer at VU Amsterdam, and editor for IEEE Pervasive Computing Magazine. He loves running.
Social:
Twitter: @altini_marco.
Personal Substack.
