uluchay

My brother just gave me a HR monitor as a present and since I don't have a power meter (probably never will) I decided to reshape my training around the HR monitor.

Until now, my training was based on my cadence reading. Like everyone suggests, I was training in the 80-100 rpm range. My regular cadence is around 88-95 rpm.

As I was looking for articles, I came up this one:

Heart rate monitor training for cyclists - BikeRadar

I'm sure most of you have seen it once or twice. It suggest that one should ride in the low intensity zone to improve the aerobic base (section "Go slower, get faster"). I decided to give it a go and I made some strange discovery; high cadence ups the heart rate!

I know there are a lot of articles on this topic and I'm reading some of them as I type this but I just feel like everything I did up to this date was wrong training. My usual average speed was around 26-28 kph for most rides and today I managed to go for two hours at 24.5 kph, trying to keep HR below 150 bpm (mostly zone 3, zone 4 on climbs) and with a cadence at around 75 rpm. I used to hate anything below 80 rpm. Today I felt really comfortable. After a 2h ride, I can say that I'm not even slightly tired.

Every time I tried to up the cadence, even with ridiculously low gears, my heart rate spiked over 160 bpm. Only on a few low gradient declines I managed to get 80 rpm.

Is this something my body should or can learn? I would love to ride at 90 rpm with a low HR.

Spld cyclist

Low or moderate-intensity training should be determined in relation to your current level of fitness. I would determine your lactate threshold HR and base zones off that.

CharlyAlfaRomeo

Low HR is relative to your LTHR and nothing else so you need to determine that first of all.

Beyond that what you want is achievable if you're willing to spend the time. Lots of longer (2 hours or more, increasing in length as fitness increases) Zone 2 rides at your target cadence (90 is a good spot to aim for) and over time your speed will go up relative to your HR. You'll need to re-test your LTHR periodically as it should go up and recalculate your zones accordingly.

Some of the benefits of this kind of base building are increased capillary density in your muscles, higher mitochondrial density in your cells, increased use of fat as fuel and a higher aerobic limit.

hamster

There is an optimal cadence for every level of effort / power. If you spin too fast at a given power output, your metabolic efficiency goes down, which means that your body needs to burn more fuel and oxygen to produce the same amount of power, which means that your HR goes up. If 75 rpm is what minimizes your HR at constant speed near your LT, no need to fight it. (If you really want to, IIRC, weight training for your legs helps raise optimal cadence by strengthening your fast-twitch fibers.) Though 75 is pretty low compared to most people. Maybe you have relatively short legs and long crank?

uluchay

I don't think that's the case, I have 32" inseam and I spin 172.5 cranks.

Carbonfiberboy 

It's "just" training. Adaptation. Right now, your muscles are fighting each other - they don't fire at the right time. So of course high cadence increases your HR. It will for everyone or almost everyone, no matter how they train, but to a small enough degree that it doesn't go up enough to worry about.

Like almost all training, the way to force adaption is to ride outside your normal envelope. The easiest way is to do this is on your trainer or rollers. It can be done on the road, but the road saps your focus and makes you worry about silly things like your speed. I assume that you're using clipless pedals, without which cadence training is mostly useless. I also assume you have cadence output on your bike computer, or you wouldn't have made this post. If you don't have a trainer, just doing this one drill is reason enough to buy a cheap one now. Anyway, try this:

Warm up at an easy pace or zone 1 for 15 minutes at your ordinary cadence. Then put the bike in a very low gear, like 39 X 27 or something really low. Increase your cadence until you start bouncing on the saddle, then decrease it just enough so that you aren't bouncing. Keep a tight chain - never allow it to go slack or bounce. Pedal with your shoe uppers. Imagine that there's a cushion of air between the sole of your foot and your shoe. Keep your feet flat and relax your toes. Hold that steady cadence for 15 minutes. It may hurt. Then pedal easy again for 15 minutes for recovery. You want to keep your HR in zone 2 while you are doing this. You may get up into zone 3 when you first start, but don't push your HR up too much. This is supposed to be a recovery drill and it will be in time. You will be shooting for a cadence of 115-130. This may sound unattainable. It is not, but it may take a couple years to be able to ride at that cadence and stay in zone 2.

Do this drill once a week. When you can hold it for 15 minutes and feel OK at whatever cadence you can manage and not bounce, increase the time gradually, over a period of weeks, until you are holding a high cadence for 45 minutes without a break. The without a break part is very important.

Cadence has nothing to do with fast or slow twitch muscle fibers. Fiber use has to do with power output, which has to do with muscle fiber recruitment. This drill emphasizes slow twitch fibers since they are done at such a low effort, and slow twitch fibers are what will get you up a climb.

hamster

Yes, it does. All else equal, higher share of recruited fast-twitch fibers means higher optimal cadence. As power goes up, more fast-twitch fibers are recruited, therefore optimal cadence goes up too. See figure 1 here https://www.me.utexas.edu/~neptune/Pa...e32%287%29.pdf

Rowan

Try changing your diet to include more carbohydrates when you ride.

Carbonfiberboy 

I don't believe the OP is talking about his HR increasing with increasing power and therefore speed. IMU he's saying his speed is decreasing with higher cadence even though his HR is higher ("even with ridiculously low gears"), IOW power is lower at higher HRs when pedaling at higher cadence.

Of course if one keeps pedaling faster in the same gear power and HR will both go up, and as they go up fast twitch fibers will recruit when the capacity of some percentage of the slow twitch are exceeded. And of course at high power high cadence means a less forceful contraction with each stroke.

The referenced study averages 8 subjects, only one of whom was a trained cyclist. The interesting data for a cyclist would be each individual's graph as compared with their individual cycling training and experience. It is incorrect to say that high cadence demands the use of fast twitch fibers. Only high power demands such use. If this were not true, long distance riders would not spend as much of their time as possible at cadences of around 100, even at low wattage. At high cadence, slow twitch fibers fire just fine. The problem is that they have to be fired at the correct time in order to contract at the correct point in the pedal stroke. This is trainable and is what my suggested drill actually does.

I believe the OP's issue is that he would like to be able to pedal in zones 1 and 2 at a reasonable speed and 90 rpm, which is definitely trainable, even though your paper says optimal cadence at 100 watts would be 57. I think that doing a 4 hour endurance ride at 57 cadence would not be fun for most of us, even though that produced the lowest momentary average EMG of the tested riders in the referenced study.

uluchay

Actually I didn't really care much about my speed. Just the HR. Not even cadence for that matter. It just caught my eye. I tried to keep a steady HR, clear state-of-mind. I often found myself freewheeling and tried to avoid it. I was never panting, even on the worst climb which usually gives me quite a beating, I managed to keep my HR in zones 4-5. I drank before I feel dehydrated.

Let's say I'm cruising at 30 kph. Under the same external conditions (tire pressure, gradient, wind resistance, etc.) I should produce a power output of let's say 200 W. This amount is irrelevant of the gearing chosen, I can do it by spinning let's say 50x15 @ 90 rpm or 39x15 @ 140 rpm. They both require the same power output but the second spikes the HR. I often found my self shifting up in order to lower my HR.

What I want to say is, I kind of instantly became a masher. Maybe I was always a masher but didn't know. I can still go out and spin 90 rpm for 2 hours, my legs know how to do it. I just won't be possible of doing it at a zone 2 HR.