Q&A episode 149 -- base w/ intensity

I wanted to follow up on one of the Q&A topics from the most recent episode. The question was related to combining intensity with longer base rides and the potential pro/con of doing this. It seems like @trevor and the podcast team interpreted the question to mean doing a longer Z2 ride and then having the intensity at the end. In that context the advice makes sense; use sparingly if at all. The high intensity work won’t stimulate the adaptations being sought.

My interpretation of that question was actually the opposite (mind you, I didn’t read the email that prompted the topic): what if you did your intensity work first, then added Z2 work after that? In my simple brain, that might be a slight “hack” that gets much of the benefit of the Z2 work without as much time investment. The high intensity work would cause fatigue that would take 2x as much time to achieve with Z2 alone, would utilize stored glycogen, etc.

If we think about some of the research regarding fasted training, I recall that Dr. John Holley talked about studies looking at evening high intensity training (with adequate fueling) followed by sleep and then a low intensity fasted session the next morning. The protocol that Dr. Holley described seems kind of similar to what I proposed above at least in spirit. We also hear about combining heavy gym work being favorably combined as a two-a-day with low intensity aerobic training.

As a long time Fast Talk listener, I totally get that there is no substitute for the adaptations achieved by doing a single, long ride, especially for the athletes focused on longer events. But can one get 80-90% of the gains of a 4 hour Z2 ride with a set of 4x8 followed by 90 minutes of low intensity aerobic work?


I too would be interested in seeing if there is data to support the idea intervals followed by a LSD.

Anecdotally, when the weather is more pleasant I do all my intervals on the out bound leg into the wind. Then flip for a bellow LT1 1-1.5hr roll home.

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I have similar anecdotal experiences. I have seen all the indicators we talk about as being associated with productive low intensity work when doing such protocols: elevated heart rate, aerobic decoupling/cardiovascular drift, and being decently recovered the next day. I’m hoping that the science backs this up!

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@SteveHerman, great post and question!

On the data side, that’s something I’ve looked for a number of times but have not yet found anything to specifically support it. I see you already tagged @trevor for leads, so I’ll follow-up with him on the topic. Anecdotally, I’ve also experienced the same thing. It seems like a good way to overload the body and then continue working aerobically when I can’t get the full time in. While it doesn’t seem like this would be an everyday type of ride to replace your long endurance miles, I do think it’s a reasonable way to get your overload in from time to time.

Coach Ryan

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If you look at Chloe Dygert’s training pre-Worlds (2019 and 2020) she often did this. Intervals to start, followed by endurance or low tempo. I’ve been experimenting with this approach as well, and I really like the combo of i) intensity, then ii) middle of endurance range, then iii) just above endurance range (I call this endurance+ which is similar to what Jim Millar likes).

I seem to remember Dr Seiler talking about staying below VT1 to get max benefit. Once you reach a higher intensity the waste products of the work include Lactate which then needs to be oxidised as fuel. That in turn reduces the aerobic contribution of the subsequent work (I think).

Overall it would seem that starting with HIIT would mean that the Z2 work we’re looking for didn’t start until later?

But my memory plays tricks, so would like @trevor to remind me.

Hi @SteepEndDown, welcome to the forum!

To your point about lactate - that is actually a valuable fuel and not really considered a waste product any longer. The production of lactate has benefits for inducing some of the training adaptations we look for, so it is a critical piece of the training “puzzle.” If you are going too hard too often within a workout that is meant to be <VT1, then absolutely, I would agree that the goal of the workout would not be met, and there is not additional fatigue being built into the body.

On the other hand, if you started with intervals and then slid into Z2 work, your body would eventually combust that lactate by running it through the appropriate steps to bring lactate levels back to baseline. You can get lactate back to baseline in a number of minutes or quite a bit longer than that depending how hard above threshold you went, but it will happen. So I think in terms of this suggestion to incorporate intervals first, we’re achieving an overload and encouraging an adaptive response with the high lactate levels being produced, and then, like you said, starting that Z2 response a little later. I think this is a pretty novel way to approach training, and to @SteveHerman’s question it could be a good way to achieve a good overload in a shorter time frame.

Coach Ryan

Hi Everyone, interesting conversation!

Ryan makes a good point about lactate that I think is important. It’s not a waste product. It’s also important to remember that even sitting stationary on your couch, you’re producing lactate. It’s just that you are clearing it as quickly as you are producing it. So, I haven’t personally seen any evidence that producing lactate will reduce the aerobic contribution of subsequent work. In fact, there’s been some recent research showing that lactate is a potent stimulus for aerobic adaptations. That may add to the many reasons why time trialers like to do work just sub-threshold where lactate uptake is at its highest.

That’s a really good question about doing some interval work before moving into more traditional base work. I have seen other coaches do that as well and it would probably make for an interesting episode of Fast Talk at some point.

But thinking out loud, both zone 1 work and HIT work do stimulate aerobic adaptations. They just do it through different pathways. The HIT pathways plateau’s quickly but it also produces rapid adaptations. So, if you’re at the very start of the season and your fitness is low, there is a good argument to do 3-4 weeks of HIT work to get the quick adaptations before switching to base work. That way when you start doing your base work, you’re not starting at such an “unfit” level, nor do you have to wait as long for the legs to come around. That would theoretically allow you to have a more effective base season and potentially a shorter base season (which is important for Pros who have increasingly longer seasons and less time for base work.)

But just thinking out loud…


I don’t think you were asking this necessarily but I almost always do some zone 2 riding after intervals because I simply have the time and zone 2 riding is the primary way I’m filling up volume.

If I account for warmup and a brief break afterwards, my 30-30s a few weeks back took 45mins. But I was fortunate and had 2hrs to ride. So I rode another hour and some change at basic endurance intensity. Of course if you’re short on time you can’t do this.

I didn’t structure it that way for any other reason than “I did my intervals so now I’ll ride the way I ride when I’m not doing intervals” :grin:(which is most of my riding and by time mostly endurance and low tempo). In other words I’m not trying to do an overload “trick”, I’m just riding basic endurance for the primary reason you ride basic endurance.

I’ve had the same question you had except instead of higher intensity, front load a long ride with what has come to be called “endurance+”. For example, say I only have 3hrs on a given Sunday instead of longer (rare but occasionally happens). What about an hour around .75 IF before dropping down to easier .60-.65? In another galaxy far far away ppl do that with SweetSpot. I’m not suggesting that! :smiley: I think it was questions like this that have caused me to make “intensity as a substitute for volume” mistakes in the past. However, as I gather from @trevor and @ryan comments, there may be times where you can do this.

I’m injured right now so I’m not doing any of this, but curious about anyone’s thoughts.

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It seems like my best intensity workouts lately have been i) front-loaded with intensity (usually shorter FTP/FRC threshold intervals @ around 2-3 minutes, or 105% FTP intervals @ around 9 minutes) and then ii) followed with basic endurance below VT1, and finishing with iii) and Endurance+ interval of between 15-40 minutes. I usually get 10/10 scores for both intensity and endurance on these workouts (done 2x per week) and definitely feel stronger after doing them 2x per week for the last few months.

What does 10/10 score mean?

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Sorry, I didn’t mention the measurement source. I use WKO5 (from training peaks) to analyze my workouts, and one of the “insight” features gives a scaled rating for both the anaerobic and aerobic component of any workout. By 10/10, I meant that I get a score of 10 for the anaerobic component and a score of 10 for the aerobic component of the given workout. In each case a score of “10” is the maximum.

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This is definitely prescribed by coaches and I have talked to a few very high level ones who recommend this within reason. I actually got to see a power file of a world record holder pro tour rider’s workout which was 4 hours or so with 30/15’s mixed in throughout the ride. It was also done on some huge mountain roads in Europe, and I asked how the rider “recovers” in the 15 seconds while going up steep hill. The coach then said, “well his recovery wattage is just below 300w.” …yeah…