A Few Minutes with… HRV Expert Dr. Dan Plews
Dan Plews, PhD, is a sports scientist and a top expert in the area of applied heart rate variability (HRV) in athletes. Dr. Plews is passionate about endurance sport and has worked work with more than 30 Olympic and World champions in rowing, kayaking and sailing. His personal passion is Ironman triathlon, and he himself broke the amateur course record at the Ironman World Championships in 8 hours 24 minutes. Plews joined the TRIBETIC team as an advisor. Here, he explains more about how athletes use HRV to help them get into top condition, and how the TRIBETIC combination of HRV with other health markers is a game changer for people with diabetes.
Q: So how did you first become interested in HRV?
Dr. Plews: When I first started my PhD, there were a lot of papers coming out where athletes would train based on HRV. And the results of several studies were showing that if you train in accordance with your HRV, you generally improve more. And as a sports scientist and a coach, especially when working with elite athletes, we're always trying to push them to do more training. There is a close response relationship between training and performance outcomes. Those who train more will generally do better. But you can't train so much that you become fatigued and reach overtraining. So as a coach, you always ask that question: When should I do more? When should I do less? And HRV can provide the answer to that question because you can look at the data, monitor the athlete, and get an understanding of the response to the training.
Q: How does HRV work as a measure?
Dr. Plews: HRV is basically measuring the gap between heartbeats. Even though many people think so, the gap between each heartbeat isn’t always one second. It's actually changing all the time. And it’s affected by what you’re doing and your level of stress. To explain a little further, there’s the sympathetic and parasympathetic sides of the autonomic nervous system. The sympathetic side is like the fight or flight, and the parasympathetic side is the rest and digest. So someone who has poor sleep, high stress at work, eats highly refined sugars, their central nervous system will switch to a more sympathetic state. And it's fine to be sympathetic now and again—when we exercise we go into a more sympathetic state. But the problem comes when you're chronically sympathetic, which means you have low heart rate variability or HRV. The less varied your heart rate becomes, the more you are associated with being stressed. Now of course, everyone in the population will have some kind of underlying chronic sympathetic stress going on, you know, if they’re eating a standard American diet, they’re stuck in traffic, busy jobs, poor sleep, all those things contribute to your HRV. Generally, higher HRV is better, and you also want it to be reasonably stable from one day to the next, because that indicates you've got things under control. If you have massive variations from day to day, that's not good.
Q: You’ve worked with high performance athletes for years. How do you apply what you know about athletes—and as an endurance athlete yourself—to people with diabetes or prediabetes?
Dr. Plews: From a physiological perspective, athletes provide the ideal in terms of what their physiology looks like and how they behave on a day-to-day basis. It gives a benchmark of what is actually achievable. And that's quite helpful even for someone who's got a different outcome like prediabetes or diabetes. An athlete probably has one of the most healthy and robust mitochondria, whereas a Type 1 or Type 2 diabetic will be towards the opposite end of the spectrum. But you can take all the behavioral things that an athlete would do and give them to a Type 1 or Type 2 diabetic and you can hopefully achieve a similar outcome. The types of training an athlete and a person with diabetes would do would actually be very similar, it’s just the amount of activity would of course be very, very different. For a diabetic it wouldn’t be 20 to 30 hours of training a week, it would be more like five to 10 hours, tops. However, you can still achieve a similar, healthier outcome in people with diabetes by applying similar behaviors.
Q: How has wearable technology changed the landscape for people to play an active role in their own health?
Dr. Plews: Now that wearables are more long-term and continuous, compliance by the user is high. It informs them about their metabolic health on a on a day-to-day basis. And there’s something called the Hawthorne effect, which is where people know they're being watched or monitored, and they will actually modify their behaviors for the better. You may have had experience with keeping a food diary and if so, you may have eaten better that week knowing you were going to be writing it down. It’s the same thing with wearable technology—people are more active because they know they’re supposed to be. So wearables have allowed people to take a more active role and are also sort of serving to motivate them as well.
Q: TRIBETIC doesn’t just look at HRV; it also looks at blood glucose and sleep and how all of them combined together are a signal of a person’s metabolic health. Why is it important to look at multiple measures as opposed to each of these measurements alone?
Dr. Plews: We know that having a low and stable blood glucose is linked to better health outcomes, but health isn't just about one thing. If you only measure blood glucose, you could eat bacon day in and day out and have a low and stable blood glucose. But you know that’s not telling the whole story. So you have to look at HRV, which is a global marker of the central nervous system and has been linked to overall health. And you have to look at sleep, because we know that lack of sleep can increase blood glucose. So these three behaviors—sleep, exercise, and nutrition—are the three pillars that are so important for general health and well-being.
Q: And not only does TRIBETIC show you your metabolic health score combining all three markers, but they also layer on the live coaching. Why is that key to being successful in a program like this?
Dr. Plews: Well, if you're a scientist, you're in the business of “interesting,” but as a sports scientist, you're in the business of “useful.” Knowing your blood glucose and knowing your HRV is interesting, but it's only useful when you tell people how to behave based on the data. So let’s say you've got a Type 2 diabetic and they say, Okay, you've told me my blood glucose is high and you’ve told me my HRV is low. So what now? What do I do? The real difference with TRIBETIC is it provides guidance for behavioral changes that can help you make shifts in those markers.
Q: Why is TRIBETIC unique? Why is it a program people should try?
Dr. Plews: There are other things on the market, but they’re only captivating the blood glucose side. For me the two most important markers in terms of health and well-being are HRV and blood glucose, and TRIBETIC is first product ever to bring those two together. And TRIBETIC is the first-ever product that's coupling both HRV and blood glucose with sleep, which is just a game changer as far as I'm concerned.
Q: You’ve worked with high performance athletes for years. How do you apply what you know about athletes—and as an endurance athlete yourself—to people with diabetes or prediabetes?
Dr. Plews: From a physiological perspective, athletes provide the ideal in terms of what their physiology looks like and how they behave on a day-to-day basis. It gives a benchmark of what is actually achievable. And that's quite helpful even for someone who's got a different outcome like prediabetes or diabetes. An athlete probably has one of the most healthy and robust mitochondria, whereas a Type 1 or Type 2 diabetic will be towards the opposite end of the spectrum. But you can take all the behavioral things that an athlete would do and give them to a Type 1 or Type 2 diabetic and you can hopefully achieve a similar outcome. The types of training an athlete and a person with diabetes would do would actually be very similar, it’s just the amount of activity would of course be very, very different. For a diabetic it wouldn’t be 20 to 30 hours of training a week, it would be more like five to 10 hours, tops. However, you can still achieve a similar, healthier outcome in people with diabetes by applying similar behaviors.
"TRIBETIC is the first-ever product that's coupling both HRV and blood glucose with sleep, which is just a game changer as far as I'm concerned." —Dr. Dan Plews
Q: How has wearable technology changed the landscape for people to play an active role in their own health?
Dr. Plews: Now that wearables are more long-term and continuous, compliance by the user is high. It informs them about their metabolic health on a on a day-to-day basis. And there’s something called the Hawthorne effect, which is where people know they're being watched or monitored, and they will actually modify their behaviors for the better. You may have had experience with keeping a food diary and if so, you may have eaten better that week knowing you were going to be writing it down. It’s the same thing with wearable technology—people are more active because they know they’re supposed to be. So wearables have allowed people to take a more active role and are also sort of serving to motivate them as well.