BE AHEAD podcast

BE AHEAD. podcast EP4: what defines being fit?

BE AHEAD. podcast EP4: what defines being fit?

In this episode, your hosts Kim and Jeroen will be discussing being fit and healthy. But what does being fit actually mean? How is it defined and how is it measured? And most of all, how can you improve your fitness level? In this episode, we will discuss this topic based on VO2Max. Press play!


Introduction: who are the hosts?

00:00 (Kim ter Stege)

Welcome back to BE AHEAD. podcast by Train.Red. My name is Kim ter Stege, I'm part of the Train.Red team and I'm the host of this podcast. I'm a sports enthusiast. I started my fitness journey after losing a lot of weight and I got very interested in fitness and health. I'm also a content creator. You can find me at @kimterstege across all platforms and I also have my very own podcast. I'm here with my co-host Jeroen.

00:24 (Jeroen Molinger)
Hi, my name is Jeroen Molinger. I’m the Lead Clinical Exercise Physiologist at Duke, at the Human Pharmacology and Physiology Lab, Research Program Director of the lab, and also Research Program Director of Duke Heart Transplantology at the Cathlab. My main focus in the research we do at Duke is all related to assessing muscle physiology and cardio-respiratory function.


What defines 'being fit'?

00:44 (Kim ter Stege)

We all like the feeling of being fit and healthy, but what does being fit actually mean? How is it defined and how is it measured? And most of all, how can you improve your fitness level? In this episode, we will discuss this topic based on VO2Max. Oxygen consumption says a lot about health, but it can also be used to determine how fit you are. Besides, it can also help you find limiting factors in your body. We talk about how to use all of this information and how to improve your performance based on it. Lastly, we talk about the usage of muscle oxygen sensors like Train.Red FYER and their best practices. So Jeroen, can you tell me a little bit more about what does being fit actually mean and how is it measured?

01:27 (Jeroen Molinger)
Thank you Kim, for this. Uh, I think one of the most important questions you, uh, you can ask regarding the use of the technology of Train.Red. I think we need to have a better understanding and kind of a deep down insight in, in what really fitness or health means. We know that the golden standard metric of, uh, overall fitness is VO2 and VO2Max in specific. And VO2Max is a, um, a metric that defines the, um, your ability to consume oxygen. And when you're looking at that specific number it's kind of intriguing to know that that number itself is an independent predictor of all course mortality and mobility that makes you less vulnerable for getting illnesses like cardiovascular diseases, diabetes. But this metric is also being utilized very well in the athlete's world, right? So that's kind of how it started off with, um, because this is a metric performance, it's the way of assessing performance of a, of an athlete in how their muscles, how their lungs, how their heart all integratively work together and which one of those systems is, is limiting in regard to their performance, which is essential to know because we know then if you have a limiting part in that whole cascade, what determines VO2, you are able to deep dive into that specific limitation and, and potentially can change it with, uh, interventions like training, uh, potentially maybe sleep, uh, sleep hygiene, uh, uh, or nutrition.

VO2 Assessment in labs or at home

02:58 (Kim ter Stege)
It's very interesting. Thank you a lot for explaining that. So can you tell me a little bit more on how you can, uh, do that VO2 assessment and how that actually works?

03:08 (Jeroen Molinger)
Sure, sure. I think it's best to, uh, to give a little bit of an insight in, in how the VO2Max is being determined. So here you see that the VO2 is the equation of cardiac outputs not applied by the amount of oxygen consumption of the muscle. This is called the Fick equation. And Fick equation is being used everywhere to determine the VO2, but also if you know two numbers of these, you can determine the third one. So what we currently will do here in our research, uh, research labs here at Duke, but also in the athlete field is that when you're measuring VO2 on the left side, we use currently here the VO2Master as a mobile device, which usually can be used for as kind of a point of care metabolic card to have a direct measurement of the VO2 kinetics. And if you combine that with FYER from Train.Red, you'll be having a better understanding in which limitations does this athlete has. So if you know those two numbers, you can always, always calculate the one in the middle of the cardiac output. So the VO2 is defined by your delivery of oxygen from the heart to the tissue, that's the cardiac output and the ability of the muscle, the tissue to utilize, uh, and to consume oxygen on a peripheral level. And that's what we're measuring with the, uh, with the NIRS device can measure the saturation. And what we're measuring is really, uh, how active is this specific muscle doing an exercise in consuming oxygen.

How is VO2Max used in sports and performance improvement?

04:42 (Kim ter Stege)
Okay, that's very interesting. So you can actually measure this Train.Red's muscle oxygen sensors can measure your consumption, but how do you actually use this data to improve your training or performance?


04:54 (Jeroen Molinger)
Yeah, absolutely. But what we need to know is then if you do a protocolized exercise test on the bike on a treadmill or, or maybe even just in the field, if you know those metrics coming from this test, you know, which was high and which was low based on the slope, when you see from a muscle that is working also a second sensor, uh, on another place currently not directly active in that specific uh, test.

How is VO2Max measured

05:17 (Kim ter Stege)
So for instance, if you would be like running or cycling, you will put one on your leg and then another on your arm?

05:23 (Jeroen Molinger)
Exactly that. Yeah. Then we can compare those two and see how fast the utilization of oxygen is more, uh, impaired on the level of the muscle instead on the level of the heart. And we also measure of course heart frequency already there. So we have then a better understanding how those kinetics go on, on the side of the heart and the side of the muscle, which then in, in, in, uh, gives us the VO2 number.

05:45 (Kim ter Stege)
And so not everyone has a VO2Master, so how do we actually measure without the VO2Master and only using Train.Red? Can you still come to this number? Yeah.

05:54 (Jeroen Molinger)
Yea, good question. I think everyone kind of struggles with that, that right be able to, to utilize this expensive, uh, expensive equipment. Uh, yes, I think, I think you can, We are, we are here currently also working with Duke in to see not only the performance of an athlete, but also military and uh, law enforcement, if you have a test done while you're still measuring for you too, what she can do one or two times a year with the combination of the Train.Red Devices, that in itself will be giving you a kind of a model, kind of a collaboration model and you know what the VO2 would be if you do the same test at home, not using the VO2Master itself, but still looking at the slopes of the, of the NIRS data, which then gives you more insight in if you are improving on your muscle level. And that in turn will give you a higher VO2. And the reason why is that, and that's kind of intriguing that mostly what we see, only high athletes will have a different limitation, but most of the people who have a limitation on the, uh, utilization of oxygen in a muscle, they are not limited by the VO2 by the heart. And the more untrained you are, the less limited you are by the, by the heart and the more limited you are by the muscle. So it's more straightforward to measuring it on the muscle level than measuring it on the heart level.

You can easily improve your VO2Max

07:12 (Kim ter Stege
So you're basically saying that not a lot of people can improve on the cardiac output, but they can really improve on the muscle part.

07:19 (Jeroen Molinger)
Yeah, exactly. That will be the, the first one that they will see adaptations on the, uh, on the muscle level. Yeah. And that makes then also the next step in, now you know, uh, and how can you define your, um, interventions like training? So you, you can define your zones pretty well based on your slopes and and, and how fast you go in specific intensity exercise. And that will give you a more better guidance to titrate your training based on your real physiology of your muscle at that specific moment in time.

How to set up a VO2Max test

07:52 (Kim ter Stege)
Okay. So what would a test like look like? You will put on a sensor on an active muscle and a resting muscle and you just do your routine, right? And then you do have numbers immediately, but there's nothing you can do immediately. You would need to, uh, do the test again, right? To see if you improved or where to yeah, make adjustments. So what would that look like? Is there any, uh, advice on how you can do this best?

08:16 (Jeroen Molinger)
Right. Um, that, that's I think one of the things everyone struggles with in how can you make it a very easy way of assessing an athlete or any, any, any, uh, amateur sporter, whatever, or even even in, uh, even an patient without going through the whole shabam of doing a exercise test in, in a, in a specific lab. But we currently do or, and probably already being, uh, what we validated here with Duke is the usage of the six minutes incremental step test. So there's a step that which you can do everywhere is stepping literally on the, on the, uh, on the place without having a step there, but really just stepping on the place with your knees high. And the incremental part is just the, uh, the pace. So we start off with a specific pace and we increased by 30 seconds with five steps a minute. And that way you can have a very well defined intensity increase. You're kind of ramping up in a very protocolized way. And when you're then still wearing that specific wearable, like NIRS sensor and you have your heart rate and you have the, a specific assessment already done with the VO2Master, so you have, you can do the same assessment only without a VO2Master itself everywhere. And then you can compare the slopes and your differences during your specific test to see if you gained or you increase your VO2. That's way because if you wanna do it on the bike, on a treadmill is always pretty hard because, um, a lab has a very specific bike and a very specific protocol, which is always very hard to reproduce in a, uh, uh, out of the lab into real life situation.

09:46 (Kim ter Stege)
Yeah, I understand. So if you wanna have like the most perfect data, you need to do exactly the same, but is it also possible for people to do the same training every time and then still see improvement? Or is that very hard to see?

10:00 (Jeroen Molinger)
No, no. I think you, you can and, and, and and, uh, not only from a a, an exercise cardiovascular perspective but also from a resistance exercise perspective. So if you do specific which is exercises like uh, deadlifts or um, uh, or squats, I think they can be beneficial for yourself just to see how fast you change doing a specific percentage of one repetition maximum (1RM) to see if you really deep dive down in your saturation on the muscle. I think the term peak performance is kind of overrated. I would rather measuring it as an efficiency. So how efficient can you be? Can you still squat a specific number, the high number of your muscle saturation? So your muscle has less issues in getting that specific power done instead of, it's still very much in the low numbers, which shows that you are using your muscles very, very intensely and it's, it's kind of coping with the, uh, specific demand of that muscle. So it's all about efficiency. Even on the sports performance stuff. Uh, we really don't know that peak itself is such a good predictor of overall performance is more how efficient can you be in how efficient on a muscle level can you be when you do your exercises.

The next steps

11:07 (Kim ter Stege)
But it is also very interesting. And what I personally like about Train.Red, I am very much into fitness, so I do a lot of squatting, lifting, benching and stuff like that. It also helps me to see my muscle recover in between sets so I can see how much oxygen is in my muscles and then I know when to start again depending on my different goals. So I think it's also not only very interesting to measure how fit you are, but also to improve training overall to see how long you need to rest. If you need to rest more, need to rest less.

11:37 (Jeroen Molinger)
Oh, I think, I think you're hitting it right at the recovery itself is presumably even I think more important than the whole exercise because the recovery period gives you two specific insights. One insight is how fast did I recover and how was the slope of recovery, which is already a metric of performance. So you are kind of assessing your readiness, but also to have the ability to titrate your rest. You can of course go for the second one when you're completely rested, but you can also determine that you want to do a second one in the middle of your recovery, which you can do every time the same. So you have a fair understanding in how do you guide your exercises, your resistance, but also, uh, sprints which can be far better titrate your, prevention, your training in yourself because your recovery is kind of the way of making it harder for the next one to come or make it less harder for the next one to come.

Get personal, train better

12:27 (Kim ter Stege)
Yeah, exactly. So I, I feel like it's very interesting to not only like improve your overall fitness, but also it can help you a lot with how to train. Like there are specific numbers like rest 90 seconds in between sets, stuff like that. But it's very personal to like everyone and also your different goals and your specific body. So it's very nice to see like how your muscles are actually working.

12:51 (Jeroen Molinger)
Uh, yeah, exactly. Absolutely. Absolutely. And also even not only on an interpersonal level, but also on an intrapersonal level. So even within your training you will see your recovery will change, uh, which you, which you don't know. And now you know, because you have the numbers there. So you can, you can choose your recovery wisely based on the goals that you are, that you're pursuing that day.


Don't test just once

13:10 (Kim ter Stege)
And I think a lot of people will be interested in like improving overall. So what do you like recommend? How often do you need to do this test? Can you do it every time? Do, do you, do you actually need to do it every single time? Is it like a once-a-month thing? What is your advice on that?

13:25 (Jeroen Molinger)
Yeah, that's a good question. I think we're still finding out what, what is the best kind of time period to assess, but on another side, the six-minute step test is a kind of a sub-maximal test. If you just normally train, which again takes you only six minutes, so around 10 minutes with the baseline and um, and the recovery period, I would advise just doing it every single week on a, on a very specific defined day and hour. So you can have a very good insight in your, in your progression and, and also just use the device during your training because it is also a way of just giving some feedback, right? It's not always doing a specific test. My approach is always that every single training is also an assessment. The training itself, how you respond on a muscle level, it should be always of interest for you to have a better understanding and how you feel and how you respond. So that gives you more knowledge about your own physiology and, and, and, and, and use this metric because it's still a for, for a lot, a lot of folks here, uh, a metric that nobody really knows how muscle saturation and muscle oxygen consumption works. So you need to be educated on your own, on your own part. You will see what you normally will do on your training and see what kind of numbers that gives you.

14:29 (Kim ter Stege)
Once a week will be ideal, let's say. I think a lot of people would like to train with it every single time, but I think there is a danger in people comparing every single training. So I think you do need to say like what you just said, if you do specific, let's say chest day on Monday, I mean, it's international chest day, right? So if you do your chest day at like 10:00 AM in the morning, it's best to do that the next week again at the same time and do the same training to see if you improved.

14:55 (Jeroen Molinger)
Exactly now. Yeah. Right. And also currently looking into in what specific day or that specific period of the day are you, uh, are you at your best, what kind of specific day, a specific period in the day do you respond the best or maybe respond the worst? So, uh, I am more of a chronotype of a, um, uh, being early or being a little bit later. So now you can also see if that somehow changes or how adaptive your muscle will be.


Warming up is important

15:22 (Kim ter Stege)
And also, one thing I wanted to loop in, like we talked about training and also resting periods, but it's also very good to see your warming up because I think a lot of people either skip it or do it not long enough. And also with Train.Red You can see if your, uh, muscles are getting more oxygen than before the warming up. Do you have anything to add to that?

15:41 (Jeroen Molinger)
Yeah, absolutely, right. I think the, the, the way of warming up was also overrated and then again, underrated again because we really not, we did not have the real good metrics of biomarkers that find that, that we are ready again, is going back to the, the whole approach of readiness and readiness is not being ready for, for a, a game, but also being ready for your specific training that, that day and that that starts, uh, getting out of bed. But also that starts when you're preparing yourself for that specific squat moment. You need to be ready on a muscle level and that's this, this way of assessing or using this data set or will give you that insight.

Will wearable data grow in the future

16:18 (Kim ter Stege)
Okay. So how do you see the utilization of wearable data in like athletes and sports people long term but also short term?

16:26 (Jeroen Molinger)
Right. Yeah, that's, that's a, that's a good question. Um, currently we have a lot of wearables. The wearables space is, uh, increasing significantly, uh, we know of course the Fitbits, the Garmins, uh, the Whoops who are out there who gives us tons of data from, from recovery, sleep hygiene, the amount of steps, heart rates and all, I think that's, that's a good thing also, uh, uh, a thing that can actually be of, uh, a struggle for people to really have an understanding about their own physiology. So I think what that needs to be done in a way of still knowing your physiology is having an app or an analytics on your phone that gives you the, the easy numbers to understand instead of the high resolution data, what will give you. That's one of our goals here at Duke, uh, here in our research to have a dashboard, a dashing of your data on a day by day base, which is easy to understand, easy to interpret, but also easy to use, during your, during your daily activities or your training or your recovery. That is still, I think, the steps you need to be taking cause everyone uses this kind of, this kind of variables constantly really don't utilize it, I think at the most they can do. And it's everywhere. It's not only about patients or athletes using this data. Even also physicians use this data. We here where Duke of course see a lot of patients, uh, on other side, I uh, we also see some healthy volunteers and potentially also, uh, some, some of these athletes in real life. There is a, there is still a big chance you become from a client athlete to being patient potentially hopefully becoming a client or athlete again who have those data in hands to have a better of understanding about your baseline physiology and how you recover. I think it's, it's of the essence also in the near future for, for physicians to understand, uh, where you are from a recovery perspective, where you are from a health perspective and even, but that's the long term in our current approach in health, measuring blood pressures, measuring heart rate or measuring glucose levels in your blood. Still kind of an old school approach. We're measuring ad hoc metric in ad hoc moments, which we choose. We need to have a more longitudinal data set to understand that the metrics like Train.Red, metrics like VO2, I would, I would think these metrics will be used even on a GP level just with your own doctor, your your uh, your family doctor because this, this is a metric, this is a vital sign that gives you insight in your overall health.

Difference between Fitbit, Garmin, Train.Red and VO2MASTER


18:47 (Kim ter Stege)
So that comes back to being fit again, like overall fitness, health. So a little bit of a question. So I do have a Fitbit and I've been using that for, I don't know, a few years now. And it do, gives me like a few insights like how my sleep was and then also I can put in my calorie intake and stuff like that. And then also during my training I can see how much calories I burn. Again, all is like more of an estimate and like it shows a little bit about your body, but I feel like for me, really the, the difference between a Fitbit and Train.Red is that I can, with Train.Red, I can actually look inside my muscles. Like it's not only about heart rate on how you can improve but also actually seeing what your muscles do. So do you have any um, insights on that on, is there a difference between like a Fitbit or a Train.Re or or VO2master, right?

19:34 (Jeroen Molinger)
That that's always the Fitbits and the Garmins are all based on optical dataset. So light that, that goes through the skin Train.Red NIRS will be having a specific way things can go and goes much deeper in inside the, yet the tissue to really get into the muscle itself. Where Fitbit only measuring is measuring the, assessing the dermis, the upper, upper layer of the skin when you can see the perfusion and the vascularization of uh, or the blood flow of that skin and that gives you the heart rate, uh, and potentially also your, your, your heart numbers there. Yeah, I think, I think it's intriguing question in why is the, that approach so different, potentially maybe less efficient to use than, than than NIRS. I think what happened is currently that this technology of NIRS was always a very novel academic tool, which only a small portion of resource is understood and used.. So it doesn't became, uh, available to the great masses and nobody really understood that right now with the FYER from Train.Red coming in, this is a completely different ball game. I think it's a more disruptive technology as we say that we use this technology would normally would cost us far more from a research perspective and now we can use it. So we are still, I think on the start of educating people in how to use this data, how do you use this metric?


Why 'being fit' is so important

20:49 (Kim ter Stege)
Yeah. Because it's like still, well not very hard to understand, but you have to put a lot of energy into understanding how it works, what data you're getting and how to actually use that to improve. Uh, of course we started off on fitness level and what being fit means, but I think we skipped over the part why it is so important to improve your fitness levels. I think we talked a little bit about it, but maybe we need a little bit more emphasis on it.

21:14 (Jeroen Molinger)
Right? Right now it's, it's very straightforward. There is only one metric. If you really want to have a metric that defines health and if you have a metric that defines health, also defines the probability of dying or the probability of having illnesses in your lifespan. That's the VO2 number. There are tons of data, tons of science there that shows that that specific number gives you the best insight in your potential risk, any illnesses or potential going to die. It's kind of weird to say how you're gonna die, but that's the number that they normally use. Also in the, uh, in the epidemic epidemiology space, it's, it's also a modifiable metric. The modifiable metric is independent of age and gender. It doesn't matter how old you are, you can always change this specific metric with specific training. And if you increase this metric in a, in a certain amount, we are calling it METS, metabolic equivalence of tasks. If you only increase that with that specific number, you decrease your chance of dying in the rest of your life with 15%. Those numbers are huge because there is no medication, there is nothing there, which can give you such amount of increase in your overall health and that number will be not static. Your number will change. Uh, if you are very healthy going for surgery, you will decline that number because there is a huge amount of stress in your system and the ability to perform will be less. But that will be equal method for you to do, uh, rehabilitation and to measure that again. And also throughout your, your training and potentially your training in a year, the number will change. Cause there are tons of stuff that that can be of uh, uh, it has a confounding factor on your, on your VO2 numbers itself. And it's good to know because it's not a static number, which is there and will always stay there.

22:57 (Kim ter Stege)

Getting just your fitness level improves is not important only for athletes and sports enthusiasts, but also for everyone. It doesn't matter if you want to do sports every single day of your life, it's important regardless.

23:11 (Jeroen Molinger)
Exactly. No, absolutely. Yeah. Every single increase that you can have, even if you're 75 and up, that's the one you need to have. Yeah. Uh, and there is no, no reason not to modify it. In order to change it for the best.



23:25 (Kim ter Stege)
Thank you Jeroen for being here with me and explaining all of this. Yeah, it was lovely having you.

23:31 (Jeroen Molinger)
Thank you. Yeah. Looking forward to the next, uh, next podcast to come.


23:34 (Kim ter Stege)

Thank you for listening to today's episode. You can find us across all social media @Train.Red. We hope to see you here next time and don't forget to follow this podcast so you don't miss out any of the next episodes. If you're interested in muscle oxygen sensors, the Train.Red FYER, go to our website Train.Red. The link is also in a description.

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