The Time-Crunched Cyclist Podcast by CTS

Will Intervals Ruin A Zone 2 Training Ride? The Science Of Mixed-Intensity Workouts. (#234)

• CTS • Season 5 • Episode 234

Share episode

OVERVIEW
There's a misconception that mixing higher-intensity intervals and Zone 2 aerobic endurance riding in the same session is bad. The contention is that exposure to higher intensities hinders the stimulus that leads to improved fat oxidation. Coach Adam Pulford dispels this myth and explains how training zones work together and can be used in additive and complementary ways.

TOPICS COVERED

  • How training intensities complement each other rather than cancel each other
  • Aspects of fitness that can be improved at ALL INTENSITIES
  • The limitation of focusing too much on improving fat oxidation
  • How progressive overload works to gradually build fitness

ASK A QUESTION FOR A FUTURE PODCAST

LINKS/RESOURCES

HOST
Adam Pulford has been a CTS Coach for nearly two decades and holds a B.S. in Exercise Physiology. He's participated in and coached hundreds of athletes for endurance events all around the world.

Listen to the episode on Apple Podcasts, Spotify, Stitcher, Google Podcasts, or on your favorite podcast platform

GET FREE TRAINING CONTENT

Join our weekly newsletter

CONNECT WITH CTS

Website: trainright.com
Instagram: @cts_trainright
Twitter: @trainright
Facebook: @CTSAthlete

Speaker 1:

Welcome back Time Crunch fans. I'm your host, coach Adam Pulford, so frame this up here. There were a few comments on a previous podcast where I gave the advice of doing some intervals Zone 3 or above that's tempo threshold or higher within the first third or halfway through a three-hour workout, then riding Zone 2 for the rest of the ride. A few comments came in suggesting this is wrong because it ruins the fat burning aspect of zone two intensity post intervals up to 30 minutes. Please hear me when I say this If you want to build fitness, improve performance and train your energy systems to be able to do more work so that you're a better athlete this month versus last month or this year versus last year, combining intervals with zone two endurance in training will help you achieve this. I was going to let it go, but as a curious person, I went looking for what other people are saying about this topic. I even talked to a couple of my own athletes about this and of course it's a very polarizing topic right now Doing intervals plus zone two afterwards versus just zone two alone and this conversation has been a cyclical sort of thing in popularity for many years now. So where's the disconnect? Why is this a polarizing topic. To stay as neutral as I can, I'll admit that physiology is a younger science we are still learning new aspects about it and how best to train athletes and the concepts overall can be very confusing. However, this confusion is amplified by influencers and talking heads that just want to get likes or go viral on the latest hype and spread false information. Quick disclaimer, though, because I do not know everything, nor do I claim that in any of these podcasts I'm still learning as well that in any of these podcasts I'm still learning as well, and everyone should be critical of the information they receive, checking their sources and making sure the advice is based on truth, even information on this podcast. But this is why, if you go to our landing page on any of these podcasts or the links in our show notes, you'll typically find a whole list of research and credible sources to back up much of the information and the advice that I'm providing, and that includes on today's show. So don't forget to do that if you want to learn more about this topic.

Speaker 1:

Now that we have the juices flowing and the disclaimers disclaimed, let's dive into why combining all intensities is so beneficial for overall performance. So let's start with that comment about zone two and fat burning. So the sexy thing about zone two is burning fat, or fat oxidation. A couple of things. One, using fat as a fuel source is really important. As an endurance athlete, this ensures that you're using your natural fuel stores properly for various intensities and can help you preserve the muscle glycogen when you need it most, ie at high intensity.

Speaker 1:

I did a podcast with CTS coach Renee Eastman entitled Don't Be a Sugar Burner, and that's episode number 169. And we talk all about this. If you want to learn more, listen to that episode. Zone two, or endurance training, as some of us call it, can help improve some metabolic aspects if you have issues there, primarily if you're burning carbs or more carbohydrate at lower intensities than you should. But you need to test in order to do that. Okay, we go through it all over on that podcast. So, um, to make sure that you have that dialed, whether you go in and have a test or you do it out in the field, um, listen to that podcast. It tells you everything that you need to know. But if you don't have issues with this which is most of us out there, by the way no need to train it and you can and are burning fat all the time at all intensities.

Speaker 1:

Wait what? Yeah, let's talk about human metabolism here for just a minute. For those who know. Nothing new here, right? For those who don't know, let me blow your mind with this. You can and are burning fat at all intensities. In fact, some athletes burn more fat as a fuel source than others, even at zone four that's threshold, people 91 to 105% of your FTP.

Speaker 1:

Now I'm not going to get into full details on this, but check out the studies I've linked to in the show notes. It is a proven fact and has been for years and years. And you know what else? You can also increase mitochondrial density at all intensities, not just zone two. You can also increase vascularity at all intensities. You can increase stroke volume and cardiac output at all intensities. You can also increase muscle glycogen storage Guess what? At all intensities.

Speaker 1:

I've got an awesome article about this. Okay, it's fast cataching. That wrote it. A bunch of his coaches over there, frank, shout out to you there, also from High North, the how and why of all this occurs. Okay, so I linked to that in the show notes. Go through and read it. But spoiler alert, they go deep into the benefits of tempo and sweet spot training when the time is right in training. So go ahead and read that. But my main point is this All roads lead to Rome.

Speaker 1:

Dr Andy Coggan has used that phrase often when answering the questions like what is the best training modality or intensities to use for different intervals? So I'll steal it here today in honor of him and because it's true. Different intervals so I'll steal it here today in honor of him and because it's true. What he means is that using all intensities and many methods to organize training can get you the same result. One way is not the way, many ways are. This is nothing new in this podcast and I've mentioned it in different ways myself, as well as with guests like Tim Cusick and Jim Miller that have strong histories of proven performance with their athletes. However, because there still seems to be a massive confusion about how training works at the metabolic level, I'm setting the stage today for more podcasts to come on these topics in the future.

Speaker 1:

The goal will be to get people like Dr Andy Coggan himself on the podcast to help explain more about why this is. Maybe even San Milan, if I can arrange it. These guys are way smarter than I am and can probably describe it a heck of a lot better. But as a coach, and as a coach running a podcast geared toward getting the right information to endurance athletes short on time, it's my job to take complicated topics, make them simple to understand and apply it to your training. And I need to do this with factual information, not just stuff that's going to blow up for a week based on hype and then slither off into nothing land. So what's the practical advice today? How can we make the advice of train all intensities and make it more simple? Well, let's talk about this training principle, because it's going to be the guiding light to help you make training decisions. That training principle is called progressive overload, and the principle states that in order to increase your fitness and or your performance, you need to increase your training stimulus or your training stress, if we want to call it that over time to keep improving.

Speaker 1:

You've heard me talk about the general adaptation syndrome on this podcast before. In fact, I think I did it last week, where I explained that the equation stress plus rest equals adaptation. In this case, training stress is agnostic. In some sense, you can use volume or intensity, or both to offer the stress to your body in a training sense. Think about TSS scores on training peaks. So long as you adequately rest, you'll form an adaptation which is getting stronger, faster, more resilient, bigger endurance, that sort of thing. Progressive overload specifies that the stress should start wherever you're at right now today and gradually increase week to week during your build weeks, then allow for some gradual detraining to occur during recovery week to make those full adaptations.

Speaker 1:

So what does this mean? How do you track it? During a phase of training, base training during a phase of base training, for example, I use CTL to track this. I make sure that the ramp rate is increasing by two to six TSS per week or so, like this for progressive weeks until I get to the point where CTL stabilizes for a few weeks. And I use mostly zone two and some zone three training for my time crunched athletes. During times of more intensive training, I'm looking at different data like mean, max power time and zone training in impact scores, kilojoule tracking and more things like this.

Speaker 1:

I've got some future episodes to talk about those in particular, but on the most simple level and let's go back to our base training example, think of it like this If you start riding and training for your first time ever. You could simply ride at endurance level or zone two, which is roughly 55 to 75% of your FTP, every day for one hour for several weeks and you can kind of keep on improving up to a point. But at some point your fitness will level out and if you want to improve you'll need to add more volume or more intensity, or both At some point. Everyone in this world levels out on volume, even Tarek Bagacha. So adding intensity is the way to add more stress. Higher intensity causes different stresses for each athlete, depending on a number of different factors, including past training history, athlete phenotype, lifestyle, sleep habits, genetics and a ton of other stuff. So many more In fact. It's hard to scratch the surface on it here.

Speaker 1:

All that to say, at an individual level, there's a lot of art that comes into the science of coaching somebody. Well, there are some norms and some general goals to aim for when we're doing high intensity interval training sessions and I have episodes coming up about all of that, including time and zone at threshold, vo two max, some anaerobic capacity. For now, let the general concept of progressive overload start to absorb and look for it in your training by observing your ramp rates or CTL going up each week or increasing time in zone at zone three or higher if you're in a phase of training where you're adding intensity right now Throughout the season. The concept is to use this progressive dosing of intensities in the right way to bring out the desired responsive adaptation at the right time.

Speaker 1:

Improving fat metabolism is only one aspect of training and it seems to be the popular choice and popular theme with Zone 2 advocates Of which is one of the biggest reasons. The zone two disciples say not to do hard intensity with your zone two days, but they're significantly losing the forest amongst the trees here. So let's summarize what we learned today. Number one you burn fat and carbohydrate and ATP, or adenosine triphosphate, as a fuel source at all intensities, including at rest and during maximal efforts. The percentage of each substrate changes as the percentage of intensity changes, but you're never purely 100% or 0% on any of them, so long as you're alive.

Speaker 1:

Stop thinking about human physiology as ones and zeros. It doesn't work like that. Nor is it really helpful to think like that. It's all sliding scales. Progressive overload may be one of the most important training principles to consider when designing and implementing training programs. So make sure in your monthly blocks you're building and dosing yourself with more each week with either volume, intensity or both. On those build weeks, then take a proper recovery week every three to four weeks and make sure that you're continually adapting. Remember, make sure to plan your recovery in Now. The third point, to summarize, is combining intervals with endurance. Riding is a great combination to deepen your fitness and practice progressive overload. If you're myopically focused on fat burning only as the benefit, you are missing out on so many other benefits of training, thus losing the forest amongst the trees.

Speaker 1:

A quick word about my background. For those watching on YouTube, you may see a sad attempt at hanging up some jerseys from athletes behind me, and you're correct. That is exactly what's happening. It is a very sad attempt. In an upcoming episode with Allison Jackson, she wondered why I didn't hang up all the stuff that she sent me, so I hit pause, I got them out and put them up like this in like 30 seconds or less. I also hung up this one here, which is a national champ Jersey from another one of my athletes, lydia Cusack, who just took fifth at cycle cross worlds. By the way. Now, because I am one of the probably the laziest coaches you'll meet. When it comes to self-promotion, I'm taking advice from those around me by being, and improving upon that in 2025. So over time, you will hopefully see a better attempt from me at celebrating my athletes achievements, like some framed jerseys in the background, for example, shout outs and social media posts when posts when they do a thing, they have a great race, as well as some athlete interviews coming up. But until then, you can definitely throw some snarky comments in on our YouTube channel. If you're watching here and shaking your head, it will improve, I promise. Trust me, I just don't know when. So that's it.

Speaker 1:

That's our show for today. If you liked what you heard, please share it with a friend, as that's the best way to grow the show. If some of what you heard today ruffled your feathers a bit, great, that means you're learning and I encourage you to head over to our landing page and check out our show notes to read more about the detail of what I went over today. And if this sparks more questions, please submit them to me by heading over to trainwrightcom backslash podcast and ask a training question. You can ask anything you want on all things endurance related and I'll do my best to answer it on future episodes and some of these future episodes will go deeper into some of these aspects by getting some other bigger names and smart physiologists on the show, because I think it's needed especially in this time and space. So be sure to come back next week and for future weeks to make sure to get all the actual training, advice and go deep into some of these complex topics. Thanks again for listening and we'll see you next week.

People on this episode

Head Shot

Adam Pulford

Host