Today I attempted to do Carillion-5. I failed to complete it as prescribed mostly because in the range of 95-100 rpms I fatigue and get winded pretty quickly. I feel as though at a lower cadence I could have completed this workout fairly easily. My ftp is currently at 240.
I have noticed this same thing when riding outdoors. When the cadence goes up I wear out quickly even when the force on the pedals is fairly light.
Is this an indication of poor cardiovascular fitness?
Yes.
Aerobic Capacity:
http://www.flammerouge.je/factsheets/vo2maxdev.htm
Training the heart:
http://www.flammerouge.je/factsheets/heartbeats.htm
More work ahead.
I wouldn’t say poor, just not good enough to maintain a high cadence. Changing your cadence gives you the option to shift the load on your body from your muscles to your cardiovascular system — or vice versa. So if one is a bit fatigued, you can tax the other more.
Also keep in mind that if you overdo it with high cadence drills, you can accumulate quite a big of fatigue on even easier workouts. I did that last week where I did 4 or 5 1-minute form sprints at 2 x 130+ rpm and 2 x 150+ rpm. The day after I had to lower my cadence to be able to finish the workouts.
It’s an indication that you’re not especially used to riding at that cadence, at least. Training that initially is going to feel harder than the same power at your preferred cadence. Coordination takes some attention and focus and the brain doesn’t work for free.
It’s an indication that you don’t train/practice that way naturally. You get good at what you do regularly. As they’ve mentioned many times, there is value in being comfortable and familiar with many ranges of cadence. 95-100 is my natural cadence. When I am trying to do “high cadence”, that is usually efforts in the 105-110 range, low cadence efforts for me are in the 80-85 range.
I used to be very similar but over the last 12 months I’ve worked at increasing my cadence by doing cadence pyramids and on gradually increasing cadence on long endurance intervals when I’m on the turbo. It didn’t happen overnight but now 90 rpm feels sort of normal for me whereas before 75/80 was my comfortable range.
Could be that you are just better suited to a lower cadence…
My personnal experience: I spent a couple of year trying to increase my cadence, and felt I was plateauing / not getting any stronger. Last year I decided to use higher cadences (85-100) for low power stuff, but let my cadence settle where it wanted (65-80) on climbs and longer intervals at or above FTP. I feel much more durable doing this.
This year I spent a lot of the base phase splitting my longer sweet spot intervals in a few minutes at 60rpm and a few at 100 rpm, rinse and repeat. I feel it made me more comfortable at whichever cadence I chose. I now know that 20 min at FTP at 60 rpm won’t kill me although it feels highly unsustainable at first. I also know the same goes for 100 rpm.
All this to say that higher cadence is beneficial for most, but maybe not for all. Just my opinion, and my experience. Your mileage may vary 
Thank you for all of the replies. This gives me something to work with.
I think this is a good strategy and accomplishes the goal that is actually important: increase the range of cadences you feel somewhat comfortable at. The self-selected cadence may differ depending on power output, fatigue levels, whether you are climbing or not, etc. E. g. on a mountain bike I’d tend towards lower cadences, for example, than on a road bike. Just experiment and don’t assume because you are bad at cadence x now that this is because cadence y is better for you. I discovered with time that my self-selected cadence on a road bike at speed is much higher than on my mountain bike (95–105 rpm at speed vs. 80ish rpm).
Just curious, do you think you have better sprint / anaerobic power (30-60s) compared to aerobic power (say threshold and sub-threshold)?
Chuffin’ Nora! 
Are you an ex-pro rider?
I’m anywhere from 20th percentile at 5s to 80 or so at 20mins. Then again the 60-69 group could have a load of ringers 
The brown line is the one to look at, the others are either past seasons or filtered in some way.
I default to 80 rpm if I’m not paying attention, and there’s nothing wrong with that (built that habit from mountain biking that rewards a taller gear) - in the last several years I’ll go on certain rides with the goal of lower power but a higher cadence. After practicing this I’m comfortable at up to 105 rpm. I’m comfortable at 70 too. Those cadence drills are designed to keep you engaged with a “boring” workout and having a wider range of riding skill at your hand when and if you need it. It’s good to establish a wider range of rpm that’s comfortable but it takes time and it’s not always something that’s worth paying too much attention to. Short form: keep practicing if it matters to you, ignore it if it doesn’t
Forgot to say…
If the workout has a few intervals say four or five and I’ll do one at 85rpm, one at 90, one at 95, etc. Sometimes the block will be a bit lower, sometimes higher but my max comfortable cadence is around 120rpm.
Lower cadence / higher torque has more muscle recruitment. However, riding higher cadence / lower torque and having it feel relatively harder does not mean you lack cardiovascular fitness. It’s just taxing your muscles in a different way.
Practice it if you want to improve it but I don’t believe that notion that your shifting from muscular / strength based to cardio based with variation in cadence is correct. It’s just leg speed
