Zone 2 cycling

How and Why to do Indoor Zone 2 Endurance Cycling Workouts

Indoor cycling has long been characterized by high-intensity interval workouts, because they are a good way to create a bigger training stimulus in a shorter period of time, they keep athletes engaged and focused, and they’re often safer and more convenient to complete on a trainer. CTS championed such workouts; they factor heavily into the training plans and concepts in the “Time-Crunched Cyclist” training books and numerous posts on this website. They work, but high-intensity interval workouts can also be over-used and lower-intensity rides have an important role in effective training plans.

About Zone 2 / Aerobic Endurance Intensity

This lower intensity is known as ‘aerobic endurance’ or ‘Zone 2‘, or in CTS terminology: EnduranceMiles. As more cyclists transition to riding indoor more frequently–because of weather, convenience, or improved technology–it is important for athletes to balance those high-intensity intervals workouts with some lower-intensity, aerobic endurance-paced, Zone 2 rides.

Why is it so hard to get cyclists to ride in Zone 2 indoors? Because it’s not as exciting as ripping through a series of hard intervals and may not provide as big a sense of accomplishment as reaching the end of an intense interval set. I get that, but if your training goal is to improve fitness so you can perform better in events (indoor or outdoor, competitive or not), then you can’t just go full-gas every single ride.

High-intensity intervals work because of the low-intensity time between them! That’s why they are typically separated by at least a full day, with that in-between day being a rest day, endurance ride, or a Zone 2 cycling workout. Sometimes hard interval workouts are scheduled in multi-day blocks to increase the concentration of workload, but even then, the blocks are only effective if recovery and/or endurance rides are scheduled immediately after the block.

As a starting point, most cyclists should only perform 2 high-intensity interval workouts per week–and this includes e-races! More advanced riders may increase this to three. With 1-2 rest days per week, this leaves 2-3 days for aerobic endurance, Zone 2 rides. The issue is getting people to actually do it.

Zone 2 Indoor Cycling Workout

The key to making a workout sticky–as in something people will stick with and complete–is to make it engaging. That doesn’t mean it needs to be complex or include gimmicks, but it typically means some variable needs to change so you have a reason not to zone out. For aerobic endurance work that stays in the EnduranceMiles or Zone 2 cycling intensity, cadence is a good variable to manipulate while the power output and perceived exertion stay relatively constant. So, the workout below stays at a consistent intensity, but includes periods of low, medium, and high cadence.

The workout is going to seem very easy for the first half, but I encourage you to stick with it rather than increasing the intensity just to feel like you’re going harder. The cumulative time at this intensity is what makes the difference, so you’re doing it right if the first half is relatively easy and maintaining the pace/power for the second half gets more challenging (but still aerobic and RPE of about 6 out of 10. NOTE: Because many athletes will be loading this workout into a device or virtual platform that bases intensity off of FTP, we have provided the intensity ranges as percentage of FTP. You can download .erg and .mrc files of the workout for use with devices, too.

EnduranceMiles with Cadence Change

Click to enlarge.

Zone 2 Indoor Workout Spelled Out

Warm up
5 min @ 40-50 % of FTP

Interval #1
Repeat the following cycle 4 times (total of 28 minutes)

EnduranceMiles/Zone 2 Cycling: Low Cadence
3 min @ 60-75 % of FTP
75-80 rpm

EnduranceMiles/Zone 2 Cycling: Medium Cadence
3 min @ 60-75 % of FTP
85-95 rpm

EnduranceMiles/Zone 2: High Cadence
1 min @ 60-75 % of FTP
100-110 rpm

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5 min @ 45-50 % of FTP
70-90 rpm

Interval #2
Repeat the following cycle 4 times (total of 28 minutes)

EnduranceMiles/Zone 2: Low Cadence
3 min @ 60-75 % of FTP
75-80 rpm

EnduranceMiles/Zone 2: Medium Cadence
3 min @ 60-75 % of FTP
85-95 rpm

EnduranceMiles/Zone 2: High Cadence
1 min @ 60-75 % of FTP
100-110 rpm

Cool Down
5 min @ 40-50 % of FTP


By Jim Rutberg,
CTS Pro Coach, co-author of “Ride Inside“, “The Time-Crunched Cyclist”, and “Training Essentials for Ultrarunning

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Comments 19

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  2. This work appears quite short for an endurance miles zone 2 work out. Many club cyclists will be used to rides 3 or 4 times as long at low intensity. Does it help maintain that kind of riding or assist with regaining the long aerobic endurance needed for those rides?

  3. What’s worked for me this winter is finding the appropriate Zwift group ride, 2.2 w/k over 100k. That’s my endurance zone and being in a group makes the 2 1/2 hours go by relatively fast.

    The key is finding the appropriate group that follows the “leader” and has a fence to zap the speed merchants.

    Before I found this Saturday morning ride, I never could imagine being on the trainer for that long at such a low intensity.

    1. Same for me. BMTR group rides are great for this. Slight increase in power (within zone) for the climbs and decrease for the recent. There’s no fence but the ride leader stays true and most follow.

      Zwift robo pace partners are also a great option. Even less variability in power output.

  4. Adam , I’m 71 years old, my FTP is 196 and my heart rate max is calculated to be 148. What is my Zone 2 for building endurance? 65% of hr or 65%-75% FT

    1. Doug:
      Two thoughts:
      1. At our age (I’m 74) the calculated max heart rate can differ significantly from our real max. A ramp test to exhaustion shows my max to be 186. Ramp tests are not for the faint-hearted (intentional pun). Doctor’s permission, and supervision, strongly recommended.
      2. Global Cycling Network recently published a Youtube video on finding your Zone 2 using perceived exertion, and shows that it correlates well with lab test results:
      Best of luck/success to you!

    2. Doug,
      Have you tried spinning for 30 minutes @65-75% of ftp to see how close your HR is to 65%?

      I’ve noticed my HR trends up for the same power, after a few hours (>3) so, % of ftp might be the more consistent reference.

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  6. Good article and advice Coach. I’ve been attempting to control my “in between HIIT days” on Zwift by free riding, but the temptation to ride >Z2 is very strong. Having a standard go-to Z2 or near recovery workout that can be ERG controlled will really help. I look forward to adding this into my weekly routine to keep me Z2 grounded.

  7. I’ve been doing lower intensity trainer workouts similar to the description for a few years now, mixing up low intensity higher cadence and big gear/low cadence, sometimes separately and sometimes combined, depending on the day. These are usually scheduled as 1-1.5hr Endurance intervals by my coach. I’ve found that as a Texas Gulf Coast flatlander that high tension/low cadence has been really beneficial for real climbing when I can finally get to the mountains. I don’t use Zwift or a “smart” trainer, just one of my retired bikes on a standard magnetic trainer. The key to success for me is to find something good on TV to watch while I’m doing it!

    1. I would try Zwift or Rouvy, if you do ride indoors 2-3 times week. really helps the time go by, & sometimes you get in a good group & hammer along, just like outdoors!

    2. i am using a single speed bike on a wind trainer. 80 years old 46/16 most of my races are short 5 K And 10 K TT Senior Games

  8. Thanks for the article. Yes, I am also doing indoor cycling exercise, but sometimes it feels I do make it look hard while practicing different exercises.

  9. I like having the variability in cadence to not lose attention during the week, but it seems like a pretty short ride if doing it on the weekend (when rained out like I am today and tomorrow) when typically longer endurance rides are on my plan so I guess maybe just doing more sets of the same for the weekends? Doesn’t seem wise risking developing an aversion for trainer rides going into the Winter trying to do 4 or 5 hours at a time, suggestions for weekend weather induced indoor rides would be great too.

      1. It’s a good question Jan. My coach always emphasised that the real benefits of the 4-6h low threshold ride only came after at least 3 hours. You have to get past that point to reap the optimum mitochondrial and capillary benefits. That said, the article doesn’t promise to deliver the benefits of 4-6h on the road, just deliver a meaningful training session at Level 2. I do these often as fill-ins between higher intensity work and as a 66 year old racing cyclist, I trust they deliver a training benefit every time. My results suggest they do. Hope this helps.

    1. Consider myself an endurance cyclist, having ridden across Canada this past summer….Now to deal with the winter! My V02 is solid at 45’ish and I love the challenge and benefits climbing provides for enjoyment and overall fitness..
      That said, I plan on spending my indoor training rides split this way:
      20% Zone 2… 60% zone 3 and 20% zone 4-and maintain for max 2 hours…I believe this approach will match closely with the style and type of riding I enjoy and expect to do when outside riding returns.
      Interested in everyone’s thoughts-I am 64 and love what riding brings to my life…

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