Fig1 : Power Output (W) vs FAT oxidation rate white from ISM paper
Was wondering if other riders notice this effect where you can actually feel the body wanting to creep out of z2.
If you look at the graph A (top) included above you can see that the rate of fat oxidation is roughly the same at 250 and 225 W being on either side of the vertex located at ~240. Of course the difference being that from 250 onward raising the power causes a quick drop off in fat oxidation as the energy system switched over. You might say that in the space between energy systems is highly unproductive in terms of fat oxidation.
However if you are out there for 2+ hours in zone 2 it can become extremely easy for the body to start raising the output to burn a bit of sugar for whatever reason be it to save fat or just to have a change up in the sensation in the legs.
This effect in particular got me thinking about those turns out of the saddle during a z2 ride and how they often tend to become more frequent towards the end of the ride and greatly reduce the RPE of the whole ride (and as a result likely diminish the effect). For example if you do a 3h straight z2 ride with no stops the last 15 minutes can be very uncomfortable, and while the correct thing to do is to rationalize by saying okay this is why I’m doing 3h to build up the fatigue to get to this part where I can now apply this unique stress to my systems, often I find myself wanting to get out of the saddle to make it more comfortable in a metabolic sense (sitting pressure aside).
My interpretation is that this is really quite bad as I mentioned above the whole point of doing a long ride is to create the opportunity for this accumulated stress so why would I then try to avoid it during the most cumulative part?
As an example I would list the following ride where I actually believe that the accumulation in a 3h ride was better than in a 5h ride, simply because the 3h ride was easier and thus required less out of saddle to complete. By that last hour of a 5h ride the quality I find does have a drop off for a number of reasons.
You can see in the cadence data where this is happening : here
So should I reduce the duration of these rides to get better quality ?
