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Podcast 108: World-Class Heart Rate Variability Researcher Dr. Daniel Plews Dives Deep on HRV

January 27, 2021

World-renowned heart rate variability expert and exercise physiologist Dr. Daniel Plews joins the WHOOP Podcast to explain how to best apply HRV data to your training.

By Will Ahmed

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Dr. Plews sits down with WHOOP VP of Data Science and Research Emily Capodilupo and VP of Performance Kristen Holmes to discuss how you can apply your HRV data to your training and what steps you need to take to avoid overreaching. He also shares his philosophy on nutrition and how to best shape your diet for the outcomes you’re looking for.

Dan is also an accomplished endurance athlete in his own right. He set a world record in his age group at the Ironman championships in 2018.


Dr. Daniel Plews Podcast Show Notes:

2:56 – A World-Class HRV Expert. Dr. Plews has published 54 papers on heart rate variability, functional resistance training, the impact of ketogenic diets, and much more.

4:08 – Researching HRV. Dan details how he began studying heart rate variability with his colleagues in New Zealand and how gaining a greater understanding of HRV could help athletes increase their performance. “We wanted heart rate variability to somehow guide and be practically applicable for training.”

6:19 – Groundbreaking HRV Findings. Dan cites a 2007 study by Antti Kiviniemi as a critical research piece in the HRV space. Emily says that paper is “foundational” to the WHOOP recovery metric.

8:25 – Training Based on HRV. Emily cites Dan’s most recent heart rate variability research paper from June 2020 in which elite cyclists were evaluated in block periodization or HRV based training programs. “In my eyes … there’s really no evidence to suggest that periodized training does anything that’s more beneficial.” Kristen and Dan also cite a 2011 research study by John Kiely.

13:57 – Three Pillars of Recovery. “It all comes down to recovery. For me, I always think of recovery as three main pillars. Those three main pillars are nutrition, sleep and training periodization. What I mean by training periodization is [how you plan] different training types.”

14:56 – Overtraining. “[People ask me] ‘Can I actually go too hard in training?’ My response is, ‘It’s impossible to go too hard. The only thing you can do [wrong] is go too hard too frequently.’”

16:51 – Day-to-Day HRV Data. “I don’t think that a one-day [HRV] measure is the way forward. I think you need to look at rolling averages. That’s always something I’ve been more of a fan of to give a better idea of what’s happening. … I’ve always thought it’s not the silver bullet and one single metric that you should look at. You need a variety of metrics to really know whether you’re going to change training or not.”

20:11 – Understanding Your HRV. Dan talks about how you can use HRV data to adapt to a training stimulus and avoid overreaching.

25:33 – Designing Workouts to Fit Your Recovery Score. Kristen and Dan talk about using the WHOOP recovery metric and data points to guide training. “I think that’s the future of scalable workouts and coaching, this guide-based coaching method,” Dan says.

27:05 – Healthy Fats and Low Carbs. Dan shares why he eats a healthy-fat and low-carb diet, and why he feels it best prepares him for endurance sports.

30:02 – Winning Formula For Ironman. Check out the online training course that helped Dan win an Ironman.

33:22 – Eating For Your Performance Goals. “Nutrition has to be specific to the outcome,” Dan argues, saying that each athlete requires a different type of nutrition plan based on the events they’re competing in.

39:22 – Training While Fasting. “Intermittent fasting isn’t really designed for people who are doing more than 10 or 20 hours a week. [If you do that], you’re in all sorts of trouble.”

Connect with Dan on Instagram and Twitter, check out his websites and, and subscribe to his weekly newsletter The Brew Up at


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Will Ahmed

Will Ahmed is the Founder and CEO of WHOOP, which has developed next generation wearable technology for optimizing human performance and health. WHOOP members include professional athletes, Fortune 500 CEOs, fitness enthusiasts, military personnel, frontline workers and a broad range of people looking to improve their performance. WHOOP has raised more than $400 million from top investors and is valued at $3.6 billion, making it the most valuable standalone wearables company in the world. Ahmed has recruited an active advisory board that consists of some of the world’s most notable cardiologists, technologists, marketers, and designers. Ahmed was recently named to the 2021 Sports Business Journal 40 under 40 list as well as 2020 Fortune 40 Under 40 Healthcare list and previously named to Forbes 30 Under 30 and Boston Business Journal’s 40 Under 40. Ahmed founded WHOOP as a student at Harvard, where he captained the Men’s Varsity Squash Team and graduated with an A.B. in government.