Endurance vs fat oxidation - same thing?

Hey all

In cycling training I’ve often seen this concept of endurance by various names, like building a base, aerobic capacity, endurance, “pushing your FTP up from the bottom” and usually prescribed by long flat z2 rides.

In triathlon circles I often hear about increasing fat oxidation adaptations, so you can draw on fat for energy for an ironman since you won’t be about to refuel with carbs fast enough to replace what you burn.

How closely related as these? Are they the same thing, ie. Is Cycling endurance ability mostly just an increased fat oxidation ability?

Or what’s the difference?

Slightly different I think.

Endurance to me is also about durability and is promoted by as you mention Z2 (and also Z1) rides.

Fat oxidation can be promoted by this also but more specifically through diet and also those Steve Neal type intervals so think of upper zone 3/sweetspot intervals done at 83% maximum heart rate and low cadence. These are supposed to increase the wattage at which the lactate balance point occurs, where carb usage=fat usage and if you go over it then you become more of a carb burner. So your LT1/VT1 and LT2/VT@ can remain the same but the lactate balance point can be trained to move towards LY2/VT2.

There are plenty of forum threads and podcasts about this google Steve Neal Tempo intervals :slight_smile:

These two podcasts from Faster - by Flo, feature Steve Neal, and are worth listening to.

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I think the simplest way to think about it is that as power increases, your fuel source shifts. At lower intensity you can use fat at a higher rate than “sugar” ( muscle/liver glycogen, blood glucose). As your power ramps up, you start to shift towards “sugar” until you get to the point where you are using all sugar and no fat (past your VT2/LT2/FTP whatever you want to say).

All training is doing is shifting that point higher. The longer you can use more fat, the longer you can go at that power. Z1/Z2 works that the most, but probably anything Z4 and below is still using some fat, so your body will still be doing some level of adaptation to prefer that fuel source, although it diminishes as the effort increases.

Keep in mind - you are always using some sugar. When you run out, your performance is going to go to hell. Training at that point is providing very little value - minimal training effect and you put yourself in a hole. If you are doing a steady state effort like a long TT or ultra ride, yes getting your fat burning power up is helpful, but if you exhaust your sugar stores, you will be limited to whatever power you can put out with just fat. Which won’t be that much. :).

So cycling endurance is a combo of what the highest level of power you can use while not going so high in power that you exhaust all your sugar. If you can keep packing sugar in, you can ride at that pace for a pretty long time. There is a point where if you haven’t trained for that duration your performance will suffer, but I suspect for a lot of people it’s lack of fueling that is a larger factor than they think.

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Thanks a lot folks. Haven’t had a chance to listen to the podcast yet but replying to this last post: that’s exactly what I’m wondering. I.e. is endurance only (or mostly) driven by your ability to use fat as a fuel source, so carb stores last longer?

I would be interested to learn if endurance could be improved without doing many long rides. Instead using shorter fasted z2 rides (eg. 90min) to improve fat oxidation and therefore endurance this way.

It’s not going to happen. If it could be possible, then the pros wouldn’t be riding long hours.

Kolie Moore (Empirical Cycling) has mentioned this many times.

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Nope, there’s also muscle and tendon fatigue. There’s no substitute for the long ride!

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Yup. The data on fasted training is pretty clear - it’s at best the marginalest of gains if you do it the right way - which is low carb the evening before and then fasted in the morning. And if you go past 45-60 minutes, probably where that small benefit ends.

Hate to keep banging the Empirical Cycling drum - it’s all about time in zone with the caveat being that once you exhaust your glyocogen - you are in zone 0. :slight_smile:

Fasted no, do not expect this to supercharge your shorter endurance rides.

Yes, in general you can ride shorter and improve endurance. However it’s riding 20-90 minutes in threshold/FTP zone. Seven years ago I did that for 9 months, a lot of 2-a-days, and it works. Excellent prep for my first and only double century.

I’ve also done a lot of 2+ hour endurance rides (fueled), and that works too.

The problem with a lot of threshold work, is actually doing that type of work consistently without burning out.