Difference between the different types of Z1 Rides

I have a question regarding the difference between the different types of Z1 Rides, being the LSD Rides (Long Slow Distance) , Aerobic Threshold Rides and the Recovery Rides.

On episode 68, it says that LSD Rides should be done 10-15 beats below one’s Aerobic Threshold HR (LT1). I assume that these are the rides I could do on the weekends 3-5hrs, once or twice week?

You mentioned that rides done at or just below one’s Aerobic Threshold HR are powerful, but you didn’t mention for how long or how many times in a week, or percentage of workouts, these should be done?

How about the recovery rides? Should they be also done 10-15 beats below one’s Aerobic Threshold HR but for a short period, let’s say 45-60mins?

Thanks in advance :+1:t2:


Hi Alex, welcome to the forum! Thanks for posting. Great questions. I’m going to tag @trevor on this one because he will have a better idea of Episode 68 and would have some great feedback for you.

To your questions:

  1. Yes, sticking 10-15 beats below LT1 would certainly fall within that 3-5 hour range 1-2x per week. And that’s the kind of ride you can do almost any time as the stress will be very low, but the payoff over time with consistency is very high. I believe Trevor was suggesting that this is something he would do more of at this time of the year. It’s just time on the bike. It gets you prepared for harder training, gets you used to just being on the saddle longer, and has beneficial effects of allowing you to build your endurance without digging too deep too early in the year.

  2. Aerobic threshold rides, when you are just at or right below that level are still very sustainable, but you do finish with a little more fatigue built up in comparison to the LSD scenario. Personally, this is something I would do 1x per week at certain times of the year, and this may be something you include as you near the start of your season. I’ll usually set aside 4-5 weeks where I can include 3-4 rides like that during that time frame. Paired with LSD and intervals, that sets me up nicely for spring and summer races. As far as duration, it’s really an individual thing. For example, my races are between 3-5 hours, so I’ll build from about 3-4 hours to upwards of 6 hours at that level to feel prepared. I generally recommend starting at a volume that you know is attainable, maybe even easy to complete. Then progress until you reach a point where you feel a little uncertain, or you just know that that particular volume/distance will leave you with an appropriate level of fatigue. In my example above, it means I’ll push past my expected race distance 1-2 times to feel confident in my abilities and nutrition capacity to fuel/hydrate on that type of ride. I’ve used this with athletes who are preparing for some very long events (e.g., DK 200) where we will block up rides where day 1 is a huge 7-8 hour day with more focus (reflected in the HR), and then day 2 is another big volume day (maybe 5-6 hours), but HR is more like 10-15 beats below LT1 since we know there is fatigue and this is now replicating some of the needs of the event. After this there are multiple off and very light days to allow the body to recover.

  3. Recovery rides - I mentioned this in our Zwift recovery spin yesterday, but my goal with recovery rides is not based on HR or power in the same sense as other types of sessions. My only goal for a recovery ride is to finish with the lowest possible power/HR. I don’t have a target that I aim for. I only aim to ensure that it is easy and I finish knowing that I went as light as possible. For example, yesterday was about 45 minutes, pretty flat terrain, 112 watts average, and 100 beats average HR (55% of maximum). As far as time, 45-60 minutes is my general time frame. With the focus being on recovery, I don’t find that most of us need more than that.

Thanks for your question!
Coach Ryan


Hi Alex, not sure I have too much to add. Ryan’s answer was great and I agree with all of it! Just a few thoughts that I’ll add:

  1. With the exception of aerobic threshold rides, don’t get too caught up in exact heart rates. These lower intensity rides, more than any other type of work, should mostly be done by feel. An LSD ride needs to be longer, but it should always feel relatively easy. For recovery rides, they should be short, but I’m a big proponent of hiding the bike computer when doing them. They’re meant to be “recovery” and that’s mental recovery as well.

  2. As Ryan said, aerobic threshold rides are very powerful and can be overdone. They should be done carefully at that target heart rate. They should also be longer. The right length is different for everyone. A way to figure out what’s right is to watch your power. There will be a point where your power will pliummet relative to your heart rate. Going about 30-45 minutes beyond that point is the right length.

Hope that helps!



Thanks @trevor! This is the key point for me. It is very easy to identify and track the point at which this happens for me. I have always assumed that (given similar workouts and conditions) the further out this happens, the better my aerobic fitness. This is especially easy to do in the controlled environment of my basement on my trainer. It’s nice to have a rule of thumb for how far I should go beyond that point when doing base work.


As a follow-up regarding what to do when HR starts to climb and power drops in Z1 @trevor. Let me see if I remember my podcasts right … In the winter base season with racing a LONG way off, I should reduce power to try and keep my HR in that ‘easy’ zone. In an aerobic threshold ride however, I should keep the power and let the HR drift up as at that point those fast twitch fibres are being pressed into service doing aerobic work, and you want that? Do I have that sorta straight?

Hi @neptuak,

Good question! Now you’re getting more into the art verses the science. The research to answer that question is being done (Dr. Seiler @stephen.seiler is one of the people working on it) so there isn’t yet a true “based on research” answer. Which means any answer is based on a mix of experience and bias.

My bias, as you already know, is to favor doing low intensity work by heart rate vs power. So, I generally recommend keeping heart rate in the right range on those long rides - even aerobic threshold rides - and letting power be what it’s going to be. The main reason for my bias is that power is external and heart rate is internal. Heart rate is showing how your body is responding. So, if you let heart rate climb, you’re changing the nature of the ride.

But, I did discuss that with Dr Seiler and as I remember, he was more on the page of maintaining power for those slightly harder aerobic threshold rides and letting heart rate climb.

All that said, you are right that as heart rate climbs later in the ride, you are forcing IIa fibers to work aerobically and there are a lot of benefits to that for an endurance athlete. What I tend to do with my athletes is have them be pretty religious about staying in the heart rate zone through most of the base season. But, as they get towards the end of base and into the early part of the season, I do like them to do longer rides where they push the power as they are starting to fatigue. And I mean not only keeping power in it’s aerobic threshold zone, but to add some sweet spot work.

However, I don’t call that a base miles ride. That type of ride has a different purpose. While it still works base endurance, it brings in some race specificity (races are harder towards the end) and it also, as you smartly point out, gives those IIa fibers a hard aerobic workout.

One last thing that may also help. I attached an image that I hope you can see. It’s an example of an aerobic threshold ride that an athlete I coach did a few years ago. His ranges are coded as colored rows behind his heart rate graph. Notice that he’s pretty consistently in the right range throughout the ride, but early on he’s at the lower end and towards the end he’s pushing the upper limit. So, he’s sticking to the right heart rate range, but still allowing some cardiac drift.

Thanks for the question!


Thank you for all the great question a and thoughtful answers here, but crazy question… Is it possible to accomplish these variants of Z1 rides without riding in larger blocks of time (I can usually find 2-3hr a day, but not at a time unless I give up on sleep)?

E.g. can I gain the benefits split 2* throughout the day?


The real trick is route planning so that you’re 30-45 minutes from home when it happens. :smiley:

j/k with experience it’s pretty easy to know what duration results in the power drop and plan accordingly. The problem comes when you plan a long ride without considering factors like distance, prevailing wind direction, elevation changes, etc

@smashsquatch, great question, and welcome to the forum! I’ve mentioned this before, but have had really good outcomes with splitting that time up with a split routine and riding 2x per day. Is it perfect? Not always. But I would recommend this over skipping sleep any day.
Coach Ryan

I was thinking about the multiple times per day thing a bit more. I remember reading/hearing that a fasted long ride and a non-fasted ride (even if eating) started to look similar from a physiological perspective after riding for a couple of hours. So could periodizing your nutrition (in this case, low glycogen availability) for shorter low-intensity rides increase the benefits gained from them? Is that benefit only fat metabolism or is it also for the other things like mitochondrial density)? I remember hearing how you should be careful and not do this often, but if your rides are always short, would it be preferential to try and have low glycogen when doing shorter Aerobic rides to gain increase benefit from them?

@smashsquatch This is just my experience with it, but I was doing 2x per day riding for months on end and saw drastic improvements in my fat oxidation (tested with a metabolic cart) and great performance improvements by focusing on doing the rides at the appropriate intensity regardless of fueling status. There were certainly some days where I might have missed breakfast getting out the door, but for the most part these were fueled rides where I consumed some kind of meal or snack before riding. At the very least, these rides did not have any type of fasting strategy built into them. You can enhance the improvements in that fat oxidation with a combination of dietary approaches and good training, but there is the risk of running out of fuel or limiting your ability to do high intensity if this is something practiced inappropriately.

To improve mitochondrial density, I always push for focusing on the appropriate intensity and duration rather than stacking a fasting strategy on top of a ride. Can it help? A bit, but I’m rather simple when it comes to the training - what’s going to give you the biggest bang for your buck? Let’s focus on that and do it well. Fasting becomes an additional piece of your training to manage for what, in my opinion, is a marginal gain. So long answer, I don’t feel that fasting, even with shorter rides, is preferential if you are performing good training and practicing good recovery.

Coach Ryan

Thanks for the feedback Ryan. Appreciate the thoughts around the fasted rides

After reviewing Trevor’s how to Low intensity ride, the one thing that pops up to me is how to target heart rate when doing split rides. For example, when doing a 40-90min ride, I can generally do it at a much higher power output than a ~2-3hr ride without seeing my heart rate climb into z3+. What’s the best way to approach this?

This raises the question about the value of those lower intensity rides where “appropriate duration” cannot be achieved.

The job time crunch means I can seldom train for more than 75 minutes on weekdays, and a combination of mental and trainer fatigue means I’m rarely able to push myself to sit on the trainer for more than 2 hours on the weekends.

Without venturing into a different training zone, is there any advantage in pushing intensity towards the upper reaches of Z1 on those 1 to 1.5h rides, where the focus isn’t on recovery, or is the ride so short that it has no effect anyway for someone with a reasonable level of fitness under the belt?

I’m in the same situation. Most of my rides are +/- 90 minutes either due to workday constraints or trainer-itis, there is a time limit I’m willing to sit on a bike and not actually go anywhere. Actually, I don’t usually take rides longer than 90 minutes on the weekends when the weather is good either due to family, house, and Dad duties.

Say I am currently doing my 1-2 workouts of FTP intervals a week, what is the concern with doing the other workouts (interval sets) slightly below Aerobic Threshold/LT1 power and heart rate? Would one be flirting with training in “no-man’s land?”

@smashsquatch and @CEBorduas, great questions. So referencing that build for the bikepacking trip, here’s a snip from one of my typical training weeks leading up to that, and it was exactly the 2x per day approach with a focus on how to ensure I can get an adaptation even though the appropriate duration cannot be achieved.

You’ll see that for the most part it’s just consistent riding, but if we dig into some of the rides, there are a couple things that stand out.

  1. I spent a lot more time in the upper end of zone 2 or into zone 3 (no man’s land). This is ok because that is still very much an “aerobic” training zone. It’s just going to require more recovery if done for a long time. The ~40-45 min rides weren’t long enough to string out recovery much more than overnight or a day.
  2. On sessions where the “feelings” were good to go hard, I’d go hard. So early in the week the PM session was a 30/30 all the way home where I was able to achieve 15 minutes just above threshold. The days in between were also based on feel and if the legs could turn over a larger gear, I’d push more into zone 3. If not, I’d keep it in zone 2.
  3. later in the week, once any fatigue was built in, I’d finish up with an achievable amount of tempo during both the AM and PM ride. Saturday was off, and then Sunday a reasonable length base ride with some harder climbing.

So to the questions of how to achieve this, I would suggest that you can get into that no man’s land at times to get the appropriate overload. Try not to be a slave to the Z1 threshold. This block referenced above was a 4 week block immediately preceding the bikepacking trip. Performance was stellar throughout and there was never a day where I felt like I needed to ride more or didn’t have the fitness. I might get slammed for suggesting going into that middle zone, but for us time-crunched athletes, I feel it is a completely reasonable place to spend some time in order to get adaptations.

Coach Ryan


I would agree. Having some level of capability in all zones is essential (or at least highly desirable). Who wants tools missing from in the shed. Coach Trevor gets a lot of grief for his current sprinting ability and I understand the likelihood of him winning a sprint is low. But I’m sure he would like to put that kid on the tricycle in his place given the opportunity. <I’m joking>

Not totally related; but, when I trained for 2 half marathons and I’m pretty sure most runs progressed from low tempo to VO2 by the end. Was it ideal? Probably not. I was blindly following the plan and running at a pace I felt “comfortable” with. Ultimately, it got me the result I was looking for.

BTW, after each race; I traded the trainers for cycling cleats and never wanted to run again.


I like the way you say it - tools missing from the shed. I like to apply this to cadence as well when working with athletes to have them become comfortable utilizing the entire spectrum of cadences.

I agree on the running progressions. Having coached marathoners in the past, we did a very similar progression and actually did quite a bit of pace runs that would have been in that no man’s land. The stuff works. It’s not for everybody, but it works.

Same here on running! Seems like every run in the past I would finish and say “never again”…until next time.

Coach Ryan

Thanks for sharing an example training week. It seems to me that there is something missing from the polarized approach. Remembering that it was developed by examining the habits of elite athletes for whom training is their job, we need to consider the time availability of the athlete. Additionally, and perhaps more importantly, the massive watts that a pro can produce means that it is simply too stressful for them to ride for extended durations in “no mans land.” Whereas, the average amateur may need a little more stimulus to cause an adaptation.

So that leads me to wonder whether the minimum effective dose to cause an aerobic system adaptation could be measured in, say, kJ’s? Is there some recovery marker that one could use to identify when the athlete is ready for a follow-on dose of aerobic training?

@SteveHerman, excellent point. I think it’s just about having a bunch of tools in your shed (to reference @Schils comment) and selecting the appropriate one for your needs. You make a great point about the polarized really being highlighted in elite level athletes. And yes, at the absolute powers and paces they are riding, running, rowing, etc. at, to have them ride in that middle zone probably doesn’t make a lot of sense due to the energy contributions required at those high absolute speeds. At the time of that example training week, there was no way I could have done “long” rides to prepare for that trip, so the only option was to bump the intensity to the middle and then hit it over and over and over again for a brief couple of weeks.

As such, for the rest of us, we might need to occasionally find ways to provide that overload to continue the adaptive process, and there are a lot of options out there. Interesting question about kJ’s to monitor. I’ve used that in the past with athletes, knowing what the demands of their events would be like. We’ve targeted certain levels of work (in kJ’s) to be completed during a ride at times and it was helpful because if they were riding slower, they would realize that it takes a lot more time to achieve a certain amount of work, and if they were riding harder, it would take less time, but might require more pacing during or recovery afterward. We know what our own “typical” rides would look like in terms of kJ’s by looking at historical data, so using that as one tool to promote our training can be helpful.

Good question on the recovery marker. Can you expand on that a bit? Is this a marker that you would use to know essentially when to push that aerobic training load further, perhaps by moving into some of the Z2 effort range? Maybe related: there was an interesting discussion on Fractional Utilization not long ago where there were some posts referencing a suggestion of a <10% difference between LT1 and LT2 as an indicator of when to incorporate higher intensity training. I was unable to find any research to support this, but it may just be something the authors from Uphill Athlete noticed in the lactate test results they were receiving from their athletes (my old lab used to do much of that testing for them, so I can see where the suggestion comes from). Since they focus very heavily on <LT1 training, this may be a novel way to indicate when you need more higher-end work.

Hope that helps!
Coach Ryan

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Yeah, I guess what I was thinking in terms of a marker is like some kind of biomarker - a “thing” that can be measured to indicate recovery. It is a slightly nebulous idea, but I was thinking in terms of a decay constant. So we add a bolus of training, measured in kJ’s, and the body recovers from that training at a certain rate. The recovery would be measured by this marker. Once the marker reaches a critical value, another bolus of work could be added. Now that I’m expanding on it, it seems like what I am grasping at the CTL/ATL decay constant in the performance manager chart and whether there is some quantitative way that one could validate the number used in that model.

I’ll have to check out the fractional utilization thread. Thanks for the cue!

You are so right about being very careful about prescribing kJ’s. One can easily end up in a death spiral in pursuit of kJ’s because at a certain point it’s simply not possible to consistently accumulate significant work at harder and harder intensities. And of course, not all kJ’s are equal in terms of the energy demands. If we stipulate that the work must be achieved exclusively aerobically, we can make some progress.

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