In this first episode of a three-part series on the Athletes Compass podcast, hosts Paul Warloski and Marjaana Rakai, together with expert Dr. Paul Laursen, explore the intricacies of High-Intensity Interval Training (HIIT). The episode delves into HIIT’s foundational concepts, physiological benefits, and strategic applications, drawing extensively on Laursen's research and his co-authored guide, "The Science and Application of High-Intensity Interval Training." The discussion offers insights into how HIIT enhances both cardiovascular health and muscular efficiency, the importance of balancing intensity for optimal training outcomes, and practical advice for implementing HIIT effectively in training regimens.

Key Episode Takeaways:

• HIIT involves short, intense bursts of activity that improve cardiovascular health and muscle fiber recruitment.
• It's essential to balance HIIT with lower intensity training to avoid burnout and optimize overall fitness.
• Understanding the physiological responses to HIIT can help athletes tailor their workouts for maximum benefit.
• Proper pacing during HIIT sessions prevents exhaustion and ensures consistent performance across workouts.
• The integration of science into training, such as Laursen's insights from "The Science and Application of High-Intensity Interval Training," aids in crafting more effective exercise programs.

• HIIT Science Book - Application of High-Intensity Interval Training

Hello and welcome to the Athletes Compass podcast where we navigate training, fitness and health for everyday athletes. Today we're talking about intervals, specifically high intensity interval training in the first of three podcasts about HIIT. Marjaana, do you know anyone we might be able to ask about HIIT?

every day at home. Today we're talking about intervals, specifically high intensity interval training. In the first of three podcasts about HIIT. Marjaana, do you know anyone we might be able to ask about HIIT?

Maybe somebody who's written a book about it?

You mean this textbook, this right here with the guy, Paul Laursen? Yeah, yeah. I think you are. We get to do this podcast with Dr. Paul Laursen, who just happens to be one of the world's top experts on HIIT Along with co-author Martin Buchheit, Paul literally wrote the textbook on HIIT called the Science and Application of High Intensity Interval Training. It's published in...

Ha ha ha!

That's right. Oh yeah. Yeah. I'm not the only one who doesn't have the textbook.

I think you are.

We could have changed that.

2019, absolutely worth your time and money to get the copy. My copy is dog -eared, covered in sticky notes and full of written notes. So here's the textbook definition of HIIT. HIIT is usually defined as exercise consisting of repeated bouts of high intensity work performed above the lactate threshold, a perceived effort of hard or greater or critical speed or power, interspersed with periods of low intensity exercise or complete rest.

Let's get down to basics. Paul, could you explain why we do intervals in the first place? Why not do only our Zone 2 endurance rides? Are we getting some physiological responses from HIIT work that we don't get from Zone 2?

Yep, perfectly. Exactly. You are. So when you're, if you just doing math training, zone two training, recovery training, just going, you know, easy for longer, which is great. And, and certainly puts down a nice base component of training. The key thing with hit training, high intensity interval training is that you click into a new gear. You move, when you move into that red zone for, uh, for just a little bit.

you start, you have to, in order to do that larger power output or the faster speed, you need to engage your larger muscle fiber motor units called fast twitch fibers, type two fibers. And you don't get those as much when you just plod in along, right, as you might expect, or just spinning your legs on the bike. So,

pretty important. And then the other thing that happens that you think that you don't get with low intensity training is your heart. Your heart beats to another gear as well. So something called your stroke volume, the amount of blood that is pushed around your body, every beat is more in high intensity interval training. And,

The other thing that I noticed that you think that you don't get with low intensity training is your heart. Your heart beats to another beat as well. So something called your stroke bone, the amount of blood.

or push your other body every week is another in my sense of the training. And yeah, there's a lot of, you know, struggling with cardiac output, blood flow, feel through my hands. It gives you, again, the skills for your heart to adapt. Then you would get, you know, would get a lot of sense of the training.

Yeah, this larger, you know, stroke volume, cardiac output, blood flow, VO2 max, it gives you again, the stimulus for your heart to adapt that you wouldn't get. And you wouldn't get in the low intensity training, the heart builds to be a more powerful working muscle in your body. And the other ones I guess are that aren't spoken about as much would be your,

built to be a more powerful working muscle in the body. And the other ones I think are, aren't spoken about as much, but the engagement of your respiratory system, your lungs. So that heavy breathing that you feel when someone's out, you know, eating your lunches, et cetera, is something that you don't get on the surface of. Lungs, hearts, muscles, all different in it, versus just the lung test that you're trying to follow.

the engagement of your respiratory system, your lungs. So that heavy breathing that you hear when someone is at, you know, VO2 max, et cetera, is something that you don't get also. So lungs, hearts, muscles, all different in HIIT versus just the low intensity training pole.

you

Awesome. We have a question from my listener. So I'm going to him a question from Paul G. He says, my understanding is that if you walk with your...

Awesome. We're all about questions from our listeners. So I'm going to jump in and ask a question from Paul G. He says, my understanding is that doing blocks of many VO2 max sessions over four weeks will raise your VO2 max quickly and then you kind of hit a plateau. But doing a longer plan of VO2 max and zone two will bring you to a higher peak VO2 max. Is this a good assumption?

Yeah, yeah, I think it's, you know, there's, I think he's kind of calling, I think it's called block training or something like that. But I've seen it, it's almost where you smash yourself repeatedly for a number of days. And you certainly would have to be careful of that type of training, especially in the running context. You can just imagine the, what would be called the neuromuscular and the musculoskeletal strain. Think of your joints and.

and tendons, that would be really hard for me at least, and probably you the listener as well, for the block training one where you just repeated daily, daily HIIT training. But in cycling, it has shown some good effect. And then, you can see how that could still be doable in the cycling context, because they're mostly, it's concentric exercises.

And then I think the second part of his question related to kind of more of the, sorry, the more of a balance, Marjaana, maybe just review it for me. The second part.

The doing longer plan of VO2 max and zone 2 would bring you to a higher peak VO2 max.

Yeah.

Well, I believe that method is more sustainable. Of course, that's the method that we use within Athletica as well, right? Where it's really, it's the ultimate balance, it's between the two. And it's a more, to me, it's just a more gentler way to get that mix of stimuli that we know are important, right? So.

And this kind of goes back to the HIIT science principles where we think about, and Phil Maffetone wrote our health chapter and he explains in the health chapter, chapter seven, how HIIT training is just fine if you are giving that HIIT training to a healthy body. That's when the body is ready to accept that type of training and recover from it.

but in the context of an unhealthy body or an overly stressed body, and then you're giving it more stress, well, that can actually be too much of a good thing and it winds up being a bad thing. And then you kind of spiral down and then it's actually inappropriate training. So there's a lot of context here in these questions that you might note. And that's what we're always all about.

at both HIIT Science and Athletica. It's like the context rules the decisions. And we're getting better and better to help you with that, with our AI. But for now, you really need to be using some common sense as any user. And you really gotta develop your own feel. And how am I feeling today? And what type of training most suits me today? Even if a HIIT session is on the calendar,

just look at that session and feel doing that session. Is that really what my body needs today? Or should I go to the workout wizard and choose something different or delete it and develop the feel to trust yourself that that decision is right? So I'll just leave it there, Marjaana. Maybe you have some comments or thoughts yourself in that experience.

Yeah, I have lots of thoughts and experience doing it wrong. But like you said, like context matters so much. And if a listener is a learner who learns best by doing a course, online course, I can highly recommend doing their heat science course.

which was excellent if you rather have done that instead of reading the book. And if you have read the book or done the course, you know that there are so many ways to skin the cat. So, I'm going back to Paul's question. In the plans, the Athletica plans, the VO2 sessions are 30 -30s.

What's the physiological response from 30 30s when compared to four by four or five by five minutes and why only 30 30s in the plans? And I guess your answer will be the contacts, but I'll let you answer that.

Yeah, yeah, yeah. So that's a great question. And we do get that often. And we'll link to this in the show notes. There's an outstanding blog that was written by Nicky Elmquist and Bent Rostad, who are big researchers in the area from Scandinavia. And they showed repeatedly in their data that you tend to get a bit more bang for buck in general.

for in the 30 -30 work versus four by four, say for example, right? Even though you actually achieve more time at your VO2 max, your power output on average tends to be a little bit higher. And the stress of the session, 30 -30 versus four, is actually lower. Now, why is that? I it doesn't make any sense, right, at first glance.

you

the reason comes back to that break period. So when you were doing 30 seconds of hard work and then you do 30 seconds of pretty much nothing, your body is still working in that 30 seconds of recovery, which is amazing, right? But there's still all of this heart contraction, like the cardiac output stroke volume is being engaged.

There's this repletion effect that's going on, the myoglobin in your muscle cells, which is like the hemoglobin of your muscle. It's re -saturating with oxygen. And it's like the whole cascade of oxygen uptake is still spinning through, but you're doing nothing. And when you're doing nothing like that, it lowers the overall stress on your central nervous system. And what Nikki and colleagues wound up showing was that in the long run,

you got a better road to Rome with respect to your ability to fast track your adaptations with the 30 -30 versus the four by four. You worked harder, so your larger fast switch muscle fibers recruited and got even more adapted. They became more fatigue resistant, because you're doing these at higher power outputs.

And yeah, and who wouldn't want that? Who wouldn't want to fast track their performance, achieve more time at VO2 max and, you know, and have it and do this at lower stress. Remember, we're always talking about the most important workout is the next workout. Well, you can actually, you know, you can probably do, there's greater probability that you'll do your next workout better.

if you do the 30 -30 versus the four minutes. Now, this is in general, and I'm not saying that you always have to do this. There's for sure a time and place for four -minute efforts, but it's just, and then you always have your workout wizard to choose that. And maybe something a little bit, if you're especially doing a workout that is, or sorry, doing a race that's going to involve high exercise intensities at four minutes,

then that's going to be really important. I think back to a girl, Theresa Adam, that I coached, I've talked about this in various different presentations. She won the New Zealand road championships and we did specific, we did specific efforts at the, you know, on a similar hill rep that was going to be in that actual race. And she, she walked away from the, she's a triathlete and she walked away from the group of cyclists.

because one of the reasons was that she had those in her plan. So there's a time and place. We had done three weeks repeatedly, a week is separating each one of those. But say it was five by three minutes was I think the actual workout. But it was very targeted and it was very specific to what we knew she needed to do in the race itself to win that race and that allowed that.

Context for everything, just like Marjaana said, but if we're generalizing, that's your answer. That's why it's in there in general, because we know you're gonna get a better road to Rome.

Yeah, I really love the 30 30s. And when I started with athletic two and a half years ago, I was coming back from overtraining and I like, I love them because they weren't that stressful. Like I felt good after. And, but now that I've been on doing 30 30s for a long time, I find that my heart rate doesn't rise as much anymore. So now I'm experimenting with 40 20s, which.

definitely is a little bit more stress and my heart rate gets higher. So I'm also liking the 40 -20s. Those are fun.

you

Yeah.

Good, good, yeah. And I know you're doing that with your buddy, Cindy Maloney as well. And I think Cindy's a little more challenged than you are, but this kind of potentially relates to the different types that are out there too, right? So I know, yeah, I know she's having a little bit more of a challenge with them. And yeah, again, this is where it's always great to experiment and recognize what works for you as an individual.

Yeah.

Yeah.

In general, we would expect someone that is more of a twitchy or hybrid profile to have a more challenging time with more time at that high exercise intensity. The twitchy athlete or the hybrid athlete will tend to be, those will be hard on them if they're going long, like the four by fours or even 40 20s, that'll be tough on a twitchy or hybrid athlete. Conversely,

a diesel engine or a, you know, someone may probably, you might be a little more of a diesel engine, Marjaana. You're going to milk up some, something like, like a four by fours or even 40 twenties. So this is where the individual thing kind of comes in. I think that, you know, I'm advancing down the road. I know that question will come potentially at a later, in a later episode. We'll talk about the different profiles that are out there and what.

types of exercises and HIIT sessions are gonna be more appropriate for them. And I'll even talk and let you in on a few secrets about what we are doing in the backend to cater for the different types of athletes. But we'll stay tuned.

That sounds exciting. I know I'm like, okay, what's going to happen? What's going to happen?

Well, let's get into our second question is from Phil in England. What is the relationship regarding training between your maximal oxygen uptake, VO2 max, and developing your maximal power?

at that uptake. I'm assuming this is on the bike. So when we do hit intervals, are we training both to increase our VO2 max and develop our power at VO2 max? Is it kind of a twofer?

Yeah, I'm so glad this question was asked because it's important to get out there. Remember that you might hear, you know, Christian Blumfeld, he's got a VO2 max of 90 milliliters of oxygen per kilogram minute. And, you know, Andy Boucher, our ambassador for Athletica.

And I think one of the times he had a score of 80 milliliters of oxygen per kilogram. So these elite guys have these really, and gals have these really high numbers of oxygen that they can consume at maximal paces and powers. At the end of the day, it's a number. It is very much related. It shows excellent correlation.

relationship to your ability to be an athlete, to perform at the highest level. So, and you know, if you're wearing your Garmin watch, you'll see this predicted number there, but it is just a number. And we have to kind of always remember that what matters at the end of the day should matter to you is your performance. And again, maybe this kind of comes back to the second part of Phil's question.

is relating to the power or pace at VO2max abbreviated in the scientific literature PV02max or VVO2max. And this can be, yeah, this is how fast you're moving at when your VO2max occurs or how much power you're producing when your VO2max occurs.

That's really, that's probably the most important thing. And even, and again, whatever that number is, is a predicted number. It might be, or you might be getting that, attaining that number very accurately if you go to a laboratory and you might actually, you know, be wearing a, one of those metabolic cart apparatus to attain that. But again, what matters to me is your, is the power and.

This is why we work within the power profile that you all have. If you're an Athletica user, you all have this in your profile. And we see around your five minute MMP or MMS, maximal mean power or maximal mean speed, if you go to the five minute mark, that's the power that's probably predicted around.

the almost the same as you would get if you went to a laboratory and spent, you know, three to $500 to get that test, you're getting probably pretty close. If you've given an honest kick at five minutes, that's probably around where that number is going to be. So I'm not sure if there's anything else you guys want to tease out from that question if I've been specific enough.

But yeah, and there will be, the number's a number. And remember like where you get to that, maybe we should just actually talk about, well, what is that number and how is it attained, right? It's maximal oxygen consumption. So it's how much oxygen your body takes in from the atmosphere, gobbles up into the lungs, transports from the lungs into the blood, and then the heart pumps that blood.

you

down to the muscles and tissues and every tissue in your body that it's consuming and uptakes it, takes it in and burns fuel and then emits carbon dioxide. And then there's an amount that comes back out. And we're looking at the difference between the oxygen that's being taken in and the oxygen amount that's being put out. And that's it. But there's a lot of other factors that are probably going into your...

overall performance and power or speed at VO2Max that you're not really measuring. And that could be related to the profile that you have if you're a twitchy athlete versus a diesel athlete. And that's kind of what I'm getting. It could be the efficiency that you go or the economy of motion. Some of us are very economical. You know, Martin Bechheit did this excellent study when he was in soccer players.

And he, so to Phil's point, he used the Cosmed K4 in some soccer players and he showed that there were some soccer players doing his fitness test that had a very high number, Phil, a very high VO2 max, but they were dead slow. Conversely, they had another other group of athletes that had very high level, or the exact same level of VO2 max, but they were moving quite quickly.

So the actual, what matters at the end of the day to all of us, how fast we move, we're looking for our local motor profile capacity. And that's, so that's all, we try to measure what matters at Athletica. So despite the excitement that we can all get around VO2Max and we can talk about this and we can put predictors out there, we care about how you're moving at various different.

profile or various different powers and times. We want to measure and help you with the things that matter. So, yeah, everything's interested and related, but that's, again, performance is sort of essential. You're going to be an individual, everyone listening, and we want to get the most out of what we can kind of see and measure.

So the higher VO2 max you have, in theory, you should be able to go faster, but that's not always the case. And that comes down to the efficiency in our physiology. So when we're talking about Kristian Blummenfelt he's got huge VO2 max. But when you're talking about looking at his body type, he's not exactly like what many associate with endurance athlete, right?

But he's incredibly efficient like what he's doing and he's got the energy to to keep going all day long at high velocity. And then you can have two athletes with the same VO2 max but I have a friend who is Swedish and our VO2 max is somewhat similar but she's way faster runner.

You know, like, my efficiency or economy running is a lower than hers. So she just leaves me in her dust every single time.

Yep, perfect. So that's exactly what we just described, right? So you want some, yeah, you want to focus on your movement at VO2max, which will always be a combination of the aerobic energy you can produce, VO2max, coupled with your exercise economy. So how economically you are in taking that aerobic energy and

outputting that to either power on the bike or running speed or swimming speed or rowing speed or whatever it may be. So VO2 plus economy equals the performance and that's what matters.

move on to our third question, who is from Phil2. Phil2, yeah. No, yeah, I don't know where Phil2 is from actually. But he's asking, I started Athletica five weeks ago following the medium volume cycling training plan.

Phil two, Phil number two, not Phil from London, Phil number two.

Prior to starting at Athletica, I had done three months of self -coached -based training. I am a 49 -year -old male with 10 years of cycling training experience. I have a question on pacing the V02 Max intervals. I've been pacing these to exhaustion so that I have nothing left in the tank for even one more interval. With the heat intervals prescribed by Athletica, should I be riding with the prescribed power band or go as hard as

Yeah, that's a really important question. Phil too, you know, you, we definitely don't want to do these two exhaustion. And, you know, the prescribed power band is there for a reason. It's, it's ideally we should be in that range, but as you develop as an athlete,

you should be starting to feel these sessions more. They should be hard and in probably in the range that's prescribed. But you should always be leaving, we say, one or two in the tank at the end. And you shouldn't be going to exhaustion on these and always thinking about the goal of the hit session in front of you. So if I've got,

two sets of eight repetitions of 30 30s. My brain, I'm like, I've nailed, I've dialed that in and I'm like, okay, I know I got to do 16 of these, you know, eight separated by a, by a recovery period and then another eight. So I'm always, I'm kind of always thinking about my last two or I still want to have some quality in the last two. I sort of want my first two repetitions to be similar.

to my last two repetitions in that block. That's where I'm, that's sort of, I'm lining up the feel. I do want, I want quality and I'm always, those last two, I'm gonna leave it, leave the session like I could have done one or two more, no problem. And that's how I wind up for these sorts of things. You can see, if you get it wrong, you see it quite clearly because you'll have a, when you look retrospectively back at your session, you'll see this fall of the,

of the power. In other words, you've fatigued as you've gone through it and you haven't done a great job of pacing. Conversely, a really good pacing profile is one that's just almost doesn't move. And this is the sign of a really well -conditioned and experienced athlete because they nail these time and time again. The other thing you should really be looking at also is your workout reserve, Athletica's workout reserve. So,

on this, this is the green line on your session analysis. And this should not, you shouldn't be out of the gates and it shouldn't be down at zero, which is like a zero battery. It should be slowly progressing down and getting towards, again, maybe plus 10 and minus 10, somewhere in that range by the end of the workout. And that's just,

that signifies that you've probably hit the target and then you can walk away. If it goes below zero, you've hit a personal best in terms of your, the maximal mean power or the maximal mean speed. According to that profile, this is always looking at your power profile or pace profile. And yeah, it was just a nice little guide. Remember also you've got that available on Phil from London's workout reserve. So yeah, that's, you can actually see this in real

I think a lot of people do the mistake of tanking themselves, me included, before I started training smarter. Every time there was heat, I would go to the well. So bad that it took me a long time to recover from. For example, I would do treadmill intervals and...

try to tank myself till I got dizzy or like that I get tingling legs. That was like a marker that I had done a heat session hard enough. So I think a lot of people can learn to train smarter and not tank themselves. Like I love the philosophy hit the target and walk away feeling like you have one or two reps in you.

And it speaks to the fact like you don't have to, you know, go with the no pain, no gain. And also leave the, as you progress in your training, leave the upper part, this is from my coach Paul, leave the upper target open so that when you get fitter, you actually, you know, like your body will dictate like what are the...

Thank you.

Excellent. Couldn't agree more.

power or pace targets on the upper level.

Yeah, that's such an important last point you just made, Marjaana. So what Marjaana is talking about is something like on a lot of the platforms that are out there, be it Zwift or TrainerRoad, you can apply the Athletica session in erg mode. And in that case, you're just going to get an absolute power output. You really don't have the option to go harder or go easier. It's erg mode. So that power on the bike in those contexts are going to be

prescribed to you. Now that can be okay and probably a really good place to start if you're just doing this for the first time because then it's like okay this is around what it's probably should sort of feel like but eventually it would be ideal if you could move towards an open sort of scenario where your brain is dictating the amount of power that's being pushed down there and you're mirroring what that erg mode would prescribe and but

In the case where you're too fatigued, you'd go a little bit lower and that's okay. And in the case where you're adapting to training and you're feeling really good, you can do more power right across the whole entire sets and show more and more progress in your, and get the most out of the session. So open or whatever that would be called. I'm not sure if you know Paul, another term for that, but.

But yeah, like that's not erg mode ultimately, where it's like you're, yeah, well, you're free to produce as much or as little power output as you want on the bike.

Yeah, just turning it off, yeah.

guess I have one question left about leaving some in the tank. If our goal is to develop more fast twitch muscle fiber, why aren't we going to exhaustion? And because that's kind of the ultimate level of recruitment of the muscle fibers.

Yep, so that's an awesome question. And just to be clear, Your goal isn't to develop more fast twitch muscle fibers. Your goal specifically is to recruit the fast twitch muscle fibers that are within you. We all have a certain amount. We can kind of actually, it's the There's a exercise physiology, long time debate and it's called the hyper...

It's basically, it's hypertrophy versus hyperplasia. Hyperplasia is like the development of more muscle fibers, like you're just sort of saying, Paul. It doesn't, what they found out eventually over a long period of research is that it doesn't happen. You never develop hyperplasia or more fast -twitch fibers or more slow -twitch muscle fibers. What you do is you convert,

that what God or mom or dad has given you and you convert those into more, say you've been given a certain amount of fast twitch muscle fibers, you can sort of turn those into more slow twitch type properties. And you do, so that's actually what we're doing. So we're saying, we've all got a certain number of fast twitch muscle fibers. We're digging into whatever we've been given. And then we actually want to make those more fatigue resistant.

So that's what winds up happening. When you do HIIT exercise, you're digging into whatever you've been given, and then you're turning those into more fatigue resistant properties or profiles. How do you do that? When you do dig into them, more mitochondria merge and come into those larger muscle fibers. And there's also this, it's a neuromuscular property as well. So it's a learned response. Sometimes if we haven't,

engaged in our large muscle fibers in a long time, we've forgotten them. They've just kind of, they've gone quiet on us. So you might need a HIIT session to re -engage and relearn to dig into those larger muscle fibers. And then when you hit those repeatedly over time, then in come the mitochondria to the rescue. And now when you're hitting those, they're super powerful.

but then you can do it repeatedly because there's more mitochondria that are taking the place and they don't feel as hard. So any lactate that's being produced by those muscle fibers winds up being quenched by the mitochondria and turning just into aerobic energy and you don't feel too much of anything. It's like, yeah, and that's the whole goal there. So that's what you're trying to do. You're trying to re -engage the larger fibers that you've,

been given and trying to make them more fatigue resistant. That's what we want to do as endurance athletes.

So can I double tap how to do the 30 -30s optimally? Obviously you could start super hard and fade away because 30 seconds is still quite a long time, but you optimally want to learn how to pace yourself all out 30 seconds. Does it mean it's as hard as all out five seconds or 10 seconds? Because if you start that hard, you'll fade.

You do.

And then the 30 seconds rest, it's just really, really easy, like barely moving your legs, right? Is that...

Absolutely, absolutely. Yeah, yeah. So I'll just give you my own experience on this. I've got a, in my head, I've got a target of between 350 and 450. That's kind of like, I know that in general, it's usually going to start slow actually. It takes me a while to warm up. I'm an old man now. So I'm, I usually sort of start my 30 30s actually now a little on the quieter side. So my first set of reps might start at 350 and then maybe progress to,

to 425 by the end. My second set is pretty solid and it's, you know, now I'm kind of, I'm really almost started targeting 400 around each one of those, right? And then it, then, you know, it might fade a little bit by the end, but more or less I'm able to kind of target around 400 for each of those. To Marjaana's point, I'm doing just turning over the legs because I know the most important focus should be on my effort phase.

I know I'll get the most bang for buck. Again, just back to Paul's question, what am I trying to do? I'm trying to make my larger fast -twitch muscle fibers more fatigue resistant. So I'm gonna do everything I can to be as quiet and soft as I can in the recovery phase. I know all the work is still going on. I love listening to my body during the recovery phase, hearing that I'm still breathing really hard and feeling my heart rate still quite high during that recovery.

and gain strength from knowing that I'm getting a lot out of the recovery phase and then boom into the next one and just try to keep that rhythm going throughout the whole high intensity interval training session of 30

those were amazing summaries. So my takeaways are gonna be really short because those two responses, Paul, were just perfect in terms of the physiology and how to do these workouts. The first one would be that, going back to the very first question, that there is a, you click into gear your muscle fiber recruitment, your cardiac output, and your lung function when you do intervals.

just perfect in terms of physiology.

going back to the very first question that there is a...

Number two is that the 30 30s, you know, provide more time and VO two max more adaptation, but the 30 seconds rest means that there's less stress. Um, this fast tracks your fitness and adaptation. And number three, you want to do your intervals just like you just said, so that the first intervals are at the same intensity or even, you know, the, the, the last ones are even stronger than the first ones. You want to keep this, um,

So that the first intervals are at the same intensity.

consistent and use your workout reserve and Athletica to monitor your intensity. So that is all for this week. Thank you for listening and join us next week when we talk again about HIIT sessions on the Athletes Compass podcast. You can help us by asking your training questions in the comments, liking and sharing the podcast, giving us five -star reviews and engaging with us on our social media for Marjaana Rakai.

So that is all for this week. Thank you for listening and join us next week when we talk again about hit sessions on the...

your training questions in the comments, liking and sharing.

and Dr. Paul Larson. I'm Paul Warloski and this has been the Athletes Compass Podcast. Thanks for listening.

Dr. Paul Larson, I'm Paul Warloski and this is been The Athletes Compass podcast.