Paul Warloski (00:18)

Hello and welcome to the Athletes Compass podcast, where we navigate training, fitness, and health for everyday athletes. Last week we talked about whether everyday endurance athletes should do intervals at the start or towards the end of a workout. This week we are dealing with another common issue for endurance athletes. Does some time at tempo or threshold or even anaerobically above zone two?

ruin the adaptations of an endurance ride. So let's talk about that first. What's the quick answer? Maybe we'll be done in five minutes here today, but I have a feeling

Paul Laursen (00:55)

Ha ha ha.

Paul Warloski (00:55)

there's going to be some more some more adaptations and more things that, you know, more depends parts of this question. So does a few seconds or minutes above zone two actually ruin the adaptations of an endurance ride?

Paul Laursen (01:08)

Yeah, I like what how you you kinda twisted that one. Does a few seconds matter? Certainly not. Absolutely and you ha you have to do this, right? So yeah, like if you if you need a to punch punch up a hill just to just to get over it, like don't worry about it. It's that's not an issue and enjoy enjoy the small little surge there, the change in posture, change in motor motor recruitment that you're gonna have in in any exercise mode. So,

That's not a problem at all. Where where it might start to confound and cause a problem is if you're always drifting into from your zone zone one, two work, your easy aerobic work, into your zone your zone three, right? Because that's what the bulk of us have the tendency to do is that we have the tendency to because it it still feels fine.

But if we're doing all of our training and a lot of it in in sort of that mid zone, zone three, that's the classic problem around polarized training that we've spoken at at length, even by its founder, Stephen Seiler who's come on the the podcast. We've spoken to at to that issue with him him there and and his daughter s Siren. So then we we can have an issue.

especially in the context of the endurance athlete that's probably training 15 hours a week or more. And if all if we constantly have our zones miscalibrated and we're constantly drifting into zone three and above, we're gonna start to develop fatigue. We're not doing enough of that easy, easy work. and that is but but a couple minutes above not a problem at all and and and probably even welcomed

Paul Warloski (02:58)

So what actually defines zone two ride from a physiological perspective? Let's start with that.

Paul Laursen (03:05)

Sure. Yeah, really good one. So we we've d we've talked about this before, but it's it's

Paul Warloski (03:09)

Mm-hmm.

Paul Laursen (03:10)

just to refresh our memory, when we're doing endurance work, aerobic work, and we we are in that there's actually a physiological we call it a demarcation, like a an actual event that occurs at steady state when you're exercising, where all of a sudden

you're moving your muscles and all of a sudden you're burning more sugar component than you are of of fat and this and at this point when you're burning all of a sudden a little bit more sugar the byproduct of that is lactate and hydrogen ions and those hydrogen ions lactate's not a problem but when all of a sudden more of those hydrogen ions the or acids

ultimately go into the bloodstream, they're they're met there by one of our key buffers, sodium bicarbonate. All right, just like baking soda. We've we're swimming in baking soda in our bloodstream. And that baking soda basically goes and and and forms more carbon dioxide. And that's sensed by this chemoreceptors in the in the carotid artery and that causes you to breathe more. So you're all of a sudden

Is that this physiological occurrence can be detected in the breath? And that's called your first ventilatory threshold. You're all of a sudden breathing higher. Your minute ventilation, your VE is all of a sudden rising up higher relative to baseline when you were in your zone one and zone two, is all of a sudden like this little bump up there. And that's that's causing, it's ultimately a little bit more stress that's in the system, right? And so you can imagine if you're always in that little bit stressed.

state. Yeah, you can feel it feels okay and you you can do it. But if you're always in there and you're always kind of breathing a little bit higher, passing, you know, you're you're bypassing the talk test, then that's more stress on the system and you're not always recovering that well from it. you d you know the recovery is reduced at if we're always doing that.

Paul Warloski (05:18)

Paul, is it a a matter of simply building up too much fatigue? Or are we talking about h adaptations that are actually being affected by kicking up in a zone three or four or five?

Paul Laursen (05:34)

Right. Well, you know, in fact, when you're kicking up into zone three, four, and five, you are adding more stress. We are causing for higher heart rates, we're causing for larger fiber type recruitments, right? We're we're shifting over from the slow twitch muscle fibers to a larger body of the fast twitch muscle fibers. And and the the adaptations we get from that are much

Paul Warloski (05:58)

Mm.

Paul Laursen (05:59)

of those that we spoke in the last podcast. We start to get more of that.

AMPK signal into those those muscle fibers and they they adapt. They that AMPK tells the the body to through PGC one alpha to make more mitochondria and they become they become more fatigue resistant the next time. So that zone three, four, five work that you mentioned is is easier the next time. And and the yeah the whole threshold, which we want to do, right? Or your critical power or critical pace you see in your Athletica

insight charts, those those rise. That's that's actually what we want. So yeah, like I think the so certainly there's, you know, back to the the central question, does that work ruin our endurance ride? Probably not. It it's it's only when we go to these extremes and we're only doing that zone three, four, five work because it's just so easy to do it, as opposed to doing more of a balanced

polarized training plan, which we recommend. That seems to be the better road to Rome.

Paul Warloski (07:06)

What I often tell my athletes is that you get, you know, the the we're we're doing our two or maybe three, depending on age and ri and training status, workouts a week, and then we still get our adaptations by going slow the rest of the time. But if we go hard during the slow times, we can't go as hard as we need to for the hard workouts.

Paul Laursen (07:28)

Yeah, absolutely. That's a such a good point, Paul. You're you're spot on. You're you're coaching perfectly with that recommendation. And and yeah, it's that is Stephen Seiler's whole premise and what he noticed. Remember his story, he's a Texan and he goes down under, or sorry, not down under, he goes, goes across, marries a Norwegian, and he lives in Norway, and he's he's

Paul Warloski (07:47)

Yeah. Yeah.

Paul Laursen (07:50)

over there and and he's observing, and he he kind of comes to the realization that they were becoming.

They were able to do their hard sessions, their that 20% of the 80 20 formula because that was the philosophy of the coaches over there, because they were doing that easy work easy, they could just rip the legs off off each other in the in the interval works to get that larger bang for buck in terms of the of the training that they actually did. So there's much there's so much benefit of that.

that lower lower exercise intensity. and and and it's for exactly the reason that you mentioned, Paul. Like it's a better, better pathway to development if we if we can have that more more balanced profile, 80, 20, but yeah, a little bit here and there, a little drift up and there. it's not certainly not gonna ruin your your endurance ride or your endurance run if you if you have just a little bit in there.

Paul Warloski (08:52)

Okay. So is zone two a a physiological state that you leave instantly once you cross V T one or V T two or V T one or L T one? or is it more like a continuum where brief excursions above L T one don't erase the signaling that you've already accumulated?

Paul Laursen (09:13)

Yeah, absolutely. So that's

Paul Warloski (09:14)

Okay.

Paul Laursen (09:15)

they they they don't. and and again you can and you can observe that be through the heart rate, right? So the the heart rate response, remember the heart rate has a little bit of a leg. So, you know, sometimes if you actually reflected on in your analysis on what your heart rate is doing, sometimes like your power or pace might go above your that threshold, that's you know, VT1, LT1.

zone two, zone three cut off. It might only go above that for for a little bit in terms of that pace and power, but the heart rate might not have even been affected, right? So but that's kind of that that's a good way to to look at things, right? You can go back and it really tells the story. If your zone zone three, if you're in heart rate zone three for much of the ride,

then that's but probably suggests that you're it's first of all, check your zones, but it also suggests that maybe you're not aerobic as aerobically developed yet, especially if you're down around the the zone one and two power or paces and heart rate is is drifting way up into zone three, zone four, right? That's kind of a classic, a classic a MAF, we call it or maximal aerobic function problem where you're not a good fat burner yet.

And you need to in that case probably slow down before you before you speed up so that your aerobic system, the fat burning system, is more developed and and you'll extend your durability later on if you do that.

Paul Warloski (10:52)

W what happens inside the muscle when we briefly or for small chunks of time exceed LT1 or VT1? Does the fat oxidation shut off? Does the mitochondrial signaling change?

Paul Laursen (11:08)

Yeah. No the well ultimately the when you're pushing the power or pace above your zone two, zone three, your muscle by necessity requires more ATP, right? That's the energy molecule. So it has to get that from somewhere. And usually what winds up happening is it re it draws higher on glycolysis, which is the the burning of your of the sugar, right? So it

It moves from the mitochondria a little bit into the cytosol, where of which is the the surroundings in the in the cell that surround the and the mitochondria are kind of sitting in that. But it draws a little bit on the cytosol to to to burn the sugar that's that's in there. And and of course lactate is the is the production or is the is the byproduct of that. So then the the and and at the same time when it does that.

The AMPK signal that we spoke about in the last podcast is also amplified and so that the next time it's going to be you know it's there'll there'll be a larger draw to to make more mitochondria because of that AMPK signal. So it's so yeah, so the yeah, you it you you push when you push into the zone three four, y you naturally

need more ATP and you get it from glycolysis and sugar burning. And and we want to l limit that as best we can because we're we're trying to make ourselves more fatigue resilient. So so yeah the the the next time it'll be a little bit better and it won't take as long. You'll the next time you do that exact same session, it will burn fat for longer and and there'll be less reliance on the carbohydrate oxidation, the glycolysis.

Paul Warloski (13:04)

When we go up a hill, for example, and get into zone three or four, how long does it take to get back to, you know, zone two state? I is that the right way of thinking about it?

Paul Laursen (13:16)

Yeah, it's i the answer is it depends. It if you're the fitter you are,

Paul Warloski (13:20)

Okay.

Paul Laursen (13:20)

the quicker it will quicker it it recovers. fit guys like Luke Evans, their heart rate recovery is almost instant. rapidly get back into the aerobic system and fat burning and i is is doing the majority of the work. And

And yeah, and then the in the case with a less fit individual, it will take a lot longer. And there'll be much more of a heart rate inertia and a longer period of of recovery that's required before it com before it comes back. So we can and we can all look at our profiles and and our data that's that's coming in to to know where we're at in these things. If you're if you're doing something like that and it's taking a long time for you to get back back back down.

y we know we ha we have we have some work to do, right? And then in the case where we're you know, we're really getting conditioned, it's giving us confidence that, yeah, we're this we're gonna be in the next race that we're gonna do, we're gonna we're gonna do well.

Paul Warloski (14:23)

Okay, that sounds good. So if you are doing a workout on a on a hilly road and you've got a two minute climb, neither running or riding, should you slow down if you are trying to build up, should you just keep going at your pace and it's okay that we let our heart rate get up a little bit? Does it matter?

Paul Laursen (14:44)

Yeah, I think it probably i the answer is d it depends. But it's

Paul Warloski (14:48)

Yeah.

Paul Laursen (14:49)

if you're in the in the situation where you don't have a lot of these high intensity moments in your in your training plan, then it's probably okay to push. And but you know, if you know you're you know, maybe at risk and you're all by yourself and you there's no one that you're with and there's no social factors around this,

then it's probably best just to chill. no no harm in walking, no harm in just easing things back. And so so yeah, a couple couple different factors there will weigh in your in your decision to punch or to or to just ease back.

Paul Warloski (15:29)

Okay. What about, you know, when I do group rides, we do town line sprints, you know, ten, fifteen seconds. What about those? Do those, you know, those kind of really short bursts, do those affect the process?

Paul Laursen (15:46)

Hmm, no. I think they're I think they're great. And you know, in the in the context of HIIT science, we have the aerobic, anaerobic, and neuromuscular system. So in the context of a 10 second sprints, you're you're really stimulating the neuromuscular system. And and that's a nice way to do it because you're you're really working on that maximal recruitment. And for only 10 seconds, it's not a huge lactate.

production system, right? So you're you're drawing on creatine phosphate and and what's called the the anaerobic alactic system. So there's not a lot of lactic lactate that's sort of produced in this. It's something about that lactate production from a stress standpoint that can really, un uncouple us in terms of our fatigue. So in the you know what you've just described there is a is a great practice because

It's also teaching your muscles and giving them the memory to in engage in those large fast twitch powerful muscle fibers that you're going to need for a race, anyways. without the huge burden of the the stress. Again, remember the key principle always, the most important session is the next session. Training consistency always wins out on any ga any day of the week. So

So you want to always do everything in in your in your power to make sure you're able to train again tomorrow, at least in some form. So by and by and those 10 second sprints, yeah, they'll be you know, might be taxing, but they're not as taxing as if you were gonna be doing, you know, one minute sprints, Paul. Like if you're doing one minute sprints, you're gonna be, looking for a bucket somewhere around if they're if they're done all out.

And that's a completely different ballgame where that's that's that's something that's very hard to to come back and and recover on. So so yeah, the ten second ones are are excellent.

Paul Warloski (17:48)

So this little the these short bouts of intensity might actually be beneficial for during a during a ride.

Paul Laursen (17:54)

Yeah, for sure. I mean those can those can be taxing eventually too, but if they're limited, then and in the context also of the phenotype we talked about last time, Paul, where we're we're looking at sprinty athletes, twitchy athletes versus diesel engines. And the twitchy athlete is probably going to need a lot more recovery between those, because their powers are probably massive.

And and then the and they don't recover as quick. And then the diesel engine, they could probably do a lot more of those because they just they can back up everything and they their aerobic machinery recovers them really quickly. So be mindful of the type of athlete that you are. If you do suspect that you are an amazing sprinter, make sure you're really cagey and conserving that that sprintability when because it can be it can be taxed.

And and and we can you know, it can lead to a lot of fatigue if you're doing those all the time. It's tempting to to really get into that and really show your stuff. our egos are always strong, but yeah, you really want to be cagey, hold those back and and and use those at the right the right time. A little more recovery for you.

Paul Warloski (19:12)

Okay. Are there situations, Paul, where keeping a ride purely zone two really does matter, like in like in the early base season or recovery weeks, things like that?

Paul Laursen (19:26)

I would say in if you are we we spoke about this on the the last podcast, Paul, where we're talked about the the the big issue is the central nervous system fatigue. And central nervous system fatigue, we're you're talking about, your brain and spinal cord and you know when you might not be sleeping well, you're training a lot, and usually we get a signal from the heart rate variability data, right? If you're monitoring your HRV on Athletica and you look at your recovery profile.

And you're looking at the seven-day rolling average relative to your normal value, which is your 60-day average, and all of a sudden it's going down and down and down. Well, now your we call it your autonomic status, the balance between your sympathetic and parasympathetic system, it's out of whack. and the there's probably more sympathetic play, fight or flight, than recovery, rest and digest. And and you you need to rest and recover.

a little bit more. So in that context where your central nervous system isn't, going strong and and you don't feel fresh, that's really a time when we want to do less of the of these sprints and keep it exclusively zone one or two. That's really where you want to have that that recovery. But in the context

where everything's normal, probably isn't going to matter too too much, Paul.

Paul Warloski (20:43)

Mm, okay. Okay. What about depend the type of athlete you are, regardless of the fast twitch, slow twitch? If you're a beginner or an elite cyclist or runner, masters athlete, time crunched athlete, does the does the answer about keeping zone two or below the th that first threshold change depending on the athlete?

Paul Laursen (21:07)

Yeah, I think in your in the context where we have our beginner athlete, this is usually the the situation where we have the MAF problem, the maximal aerobic function problem, where we have the issue where heart rate really drifts and it's hard for us to keep a a zone two heart rate. But because it's always we're we're not good fat burners yet. In that context, you definitely want to be doing our zone two sessions as zone two. So in that beginner athlete.

situation, zone one and zone two, and start to build those up. That and that should be really the the focus, the what we call it, the you know, train to train period of of the periodized plan. You really want to lay down that base. and and that's that's the time to do that. And then in the context where you're an experienced athlete, a solid MAF, small a solid base,

This where we can we can probably lighten up a little bit and and be a bit more chill on a on the odd the odd time that we that we move out of that zone two range and and and surge a little bit for fun and and and whatever it may be. So yeah, I think and then of course probably the it could also be for the the older masters athlete, often in the older cohort.

We often have the situation where stress has and work stress

Paul Warloski (22:35)

Hm.

Paul Laursen (22:36)

and life stress and has just kind of it's it's built up on us. And this can be all another confounder on the the whole MAF problem, the maximum aerobic function problem. And again, we have a drifting heart rate relative to that that pace or power that might be sitting at zone two. And this again, where we need to go back to basics and we need to again

be as mindful as we can and sticking in our zone one and zone two to area in the masters context. But then we could have the different masters athlete where they're a they're a lifelong experienced athlete with a very solid base that's behind them with no issues whatsoever. And then yeah, what we got? We got the the starter, we got the masters. Was there another one?

Paul Warloski (23:27)

The elite athlete and then time crunched athlete. What you think about that?

Paul Laursen (23:30)

Yeah.

Well, Time Crunched, there's there's a lot of context for the the Time Crunched because in that situation, you you know, it's it's what type of time crunched athlete? we have the Sammy Inkenin, who's a Verda Health founder, and he was the Iron Man age group champion for a period of time. and Sammy has a a classic story.

I interviewed him on my the training science podcast and he spoke about how he he won Kona with the record at the time and he did that on ten to twelve hours a week. But so very, you know, very focused sessions. Now he was also had a a an amazing base behind him. I believe he was a rower, so a huge aerobic engine behind him. And but nevertheless, and 10 to 12 hours a week, time crunched,

running I think it was Truella that he was a you know a his big name CEO like he already is and he yeah he was able to do that on but he had in his context a massive aerobic base behind him. You could also be the

Paul Warloski (24:36)

The yeah, the b yeah, the base.

Paul Laursen (24:38)

that same CEO on 10 to 12 hours a week or eight whatever it might be with that you can you can put in and you know you might be way overstressed and

well not as aerobically fit. And in that case, maybe maybe you're doing more zone two work in in that because your body needs it. So there's a lot of depends on here. And

Paul Warloski (25:01)

Mm.

Paul Laursen (25:02)

so I you know and I should mention like like Sammy's whole philosophy with his his 10 to 12 hours was you know very race specific almost every time. So he would he would go out and he would he would do quite a lot of high intensity work.

one long ride or or run on the weekends. but everything else was mostly race intensity specific because he only had that amount of time to do that. so there's a yeah a lot of depends on this, Paul.

Paul Warloski (25:33)

Yeah, and it sounds like the key is your your training age and how much aerobic base you have developed over the over the time that you've been training.

Paul Laursen (25:48)

Yeah, yeah, yeah, yeah. I mean, nailed it. You know, we don't talk about that enough, but that was was one of the things. I remember working in high performance sport New Zealand with the TRAFLO New Zealand program, and we were actually comparing the training ages, not the age of the athlete, but just the the training age because we had historic data on those athletes. And Alistair Brownlee was the the classic example. here was a guy.

and he's an Athletica investor. Al Alistair w had this long training age, but he was just such a young buck going through it through this when it went when we were, comparing him against everyone else. You know, he started when he was age 11, right? So and just with that consistent training. And we had data on him back from when he was, age 11. So he had this super long training age and and it related to his success. And we we see it all the time.

And it and it relates not just to the elites, but to to all of us. And and it's not it's not the be all end all. There's many examples, Chrissy Wellington, etc. People that find sport at a later age and then they all of a sudden have they f they find that they have this this amazing capacity for it. But no doubt there is this there's something about that principle of training consistency and your training age that really factors in.

to to a lot of these contextual decisions that we're talking about.

Paul Warloski (27:19)

Okay. What about nutrition? Does that change the equation if you fuel well during the ride, get in some carbohydrates if you need them? Does that minimize the cost of occasional hard efforts, or does it not matter?

Paul Laursen (27:33)

Yeah, I'm getting it's so much context here, right? So in the I

Paul Warloski (27:34)

Yeah, yeah.

Paul Laursen (27:38)

think in the fat adapted athlete, you might be you might might not need as much, but in the if you're not as well fat adapted and you you have a tendency to feel hypoglycemic, a little bit lightheaded or fatigued or or weak during your exercise.

then that's a probably a a large signal that you you need to supplement with with some form of a sweet or a carbohydrate during but so there's there's a lot of lot of nuance there. And at the end of the day you need to you need to do what works for you. And so yeah, don't don't be afraid to use what you need if especially if you need to punch up certain climbs to get yourself home or whatever it might be, right? You've got a

Paul Warloski (28:22)

Mm, yeah, yeah.

Paul Laursen (28:23)

A hill in front of you to to get across before you get home. Well, nice to have something in your in your back pouch. I remember some some rides myself. I'm sure you've got stories too, Paul, where you just like

Paul Warloski (28:34)

Mm.

Paul Laursen (28:34)

you almost have to you know, you've you're you're wondering if you can get any nutrition from the grass that's sitting on the on the side of the road as

Paul Warloski (28:40)

Ha ha ha.

Paul Laursen (28:41)

you as you lay down, right? Like I remember how bonked I've I've felt at certain times in in farm fields, in pit meadows, trying to ride home from yeah, on on

very long long rides, before

Paul Warloski (28:54)

Yeah.

Paul Laursen (28:55)

I was fat adapted. So

Paul Warloski (28:57)

Yeah. So so Paul, our our essential question today was about whether doing some kind of effort or efforts during an endurance ride is going to ruin the adaptations for the endurance ride. So if an athlete remembers something from today's episode, what would you say it should be?

Paul Laursen (29:19)

I would say it's not gonna ruin your ride, if you do do one or two surges for sure. Where the problem is could occur is if that's always your practice. If you're always surging, if you're always drifting up into zone three and that's all you ever do, and you're not kind of following this this you know, general balanced polarized program that Stephen Seiler talks about.

you, you know, you've you've gotta be a little bit more cautious there. of course there's lots of depends all around this that we've been talking through on the podcast. But but yeah, I'd say a little bit certainly don't don't sweat it, relax. And but you know, if it's if it's something that you're always doing, it's you might wanna have a little bit of more of a look at at some of the metrics and you can certainly get those through the

through Athletica and the AI coach. Just ask the coach actually to analyze your overall situation in terms of how balanced you are as an athlete in terms of the training zones that you tend to perform at. And AI coach is fantastic at going through all of your data now. It's got a memory, it's got a historical look and it can it can give in a good assessment if there's any doubt in your mind.

Paul Warloski (30:37)

Mm-hmm. Yeah. And as a coach, what I do on Athletica is I look at the athletes' session chart and then their time in zone. And that gives me a pretty good sense of in general whether they went hard during this ride or whether they stayed in mostly in zone two. and that gives me a really good especially the time in zones because their power might be over a little bit, but looking at their heart rate and what bins those zones

know, they tend to be in and that that gives me a pretty good picture.

Paul Laursen (31:08)

I agree. I I love that feature and and I

Paul Warloski (31:10)

Yeah.

Paul Laursen (31:10)

do the same. the the session the session analysis is is fantastic. So and you it's usually sitting right under your overall look at all of the, your power pace, heart rate, workout reserve, etc. But if you look usually below that, you can see the the time and zones that you can see what's prescribed and what you actually did. And if you're constantly seeing that you're out of zone in those.

That's a you know, that that's a that's a strong signal that you might wanna you know, consider how you you perform in the next session.

Paul Warloski (31:45)

Absolutely. Well thanks, Paul. I appreciate your time.

Paul Laursen (31:49)

Thank you, Paul. Great as always.

Paul Warloski (31:50)

Thanks for listening today to the Athletes Compass Podcast. Take a moment now, subscribe, share, and let's keep navigating this endurance adventure together. Improve your training with the science based training platform Atletica and join the conversation at the Athletica Forum. For Dr. Paul Larson, I'm Paul Worlovski, and this has been the Athletes Compass Podcast. Thank you so much for listening.