Then please explain these results:
Specifically, if lactate suppresses lipolysis, why did quadrupling the concentration via exogenous infusion not have any effect on plasma glycerol or fatty acid levels*, or on the overall rate of substrate oxidation?
*I misspoke on Inside Exercise when I said Ra itself. Brooks has done a number of studies using stable isotopic tracers, so I was conflating things in my mind.
The dilemma must be too challenging. 
@DrSanMillan is a bot. LOL
There are a few on the market already. Has anybody tested them yet?
I’m not aware of any continuous lactate monitors only CGM’s (continuous glucose monitors).
But they have also talked a lot about Lydiard training in the past.
I always thought that Lydiard training was lots of “slow” volume, but
they dispelled that many times. So, Lydiard training was high volume,
but not slow at all – which may be in line with San Millan’s Zone 2
(which is anything but slow).
I seem to recall them saying that Lydiard had a huge long-slow-distance base phase - like a hundred miles per week for months.
I’m really fascinated by the broken interval training. It’s interesting that the fastest runners in the world are using these techniques but they hardly exists in cycling. Some cycling coaches prescribe a few over/unders.
Yes, Lydiard had a huge volume, but not slow like many people mistakenly thought.
In one of the podcasts, they were going through one of the Lydiard’s training programs
and both were emphasizing that it’s not slow at all. I’ll try to find the reference to the podcast.
The other thing they have said about training back then is that they were often doing double and triple days. They weren’t even logging the easy morning or lunch time shakeout runs because they didn’t even count them as training. They were pre-training.
For certain sports (running, rowing, speed-skating), you have to break your training into doubles
or triples otherwise you wouldn’t be able to get enough volume. Whether doubles/triples give you
other (unintentional at the time) benefits, that’s another story.
We are mainly focusing on metabolic aspects of training (lactate, burning of CHO/fat, etc.), but there’s whole other aspect of training that is never mentioned: hormonal and enzymatic adaptations.
A great book on this topic:
Here’s Magness’ article about Lydiard:
from that Lydiard article here are my takeaways w.r.t. base work:
Good summary. I would add that lasting changes to cardiovascular system indeed take a lot of time. Increasing stroke volume takes lots of time and so does capillarization of muscles.
On the other hand, building mitochondria is surprisingly quick. You can build it up quickly, but also
lose it very quickly.
You bring up an important point about “easy” work. Namely, how easy is too easy?
The cardiovascular and metabolic (and hormonal, etc.) adaptations to training (and detraining) all follow a similar time course. What differs is the scope or magnitude of potential improvement possible.
In my experience and understanding, you can manipulate stroke volume over the course of a few weeks, but mitochondrial changes and capillarization take a long time (months). Blood volume can also come around relatively quickly and for most people who are coming off of breaks, the dropoff in performance that we experience after extended time off followed by relatively rapid improvement upon reintroduction of training is usually due to increased blood volume.
I have numerous examples of improved performance likely attributable to stroke volume improvements following relatively short training durations of 3-6 weeks, primarily indicated by improved EF across several intensity levels. These are generally blocks of specific VO2max work that elicit these changes.
Happy to be corrected on any of that by Andy or whomever. Just sharing practical experience here. I’m no physiologist.
Consider yourself corrected.
The half-life of mitochondrial proteins is very short, on the order of 1 wk or so. It therefore doesn’t take long to increase mitochondrial respiratory capacity - the difference between this response and, say, the increase in VO2max lies in the scope or magnitude of total improvement possible, not the rapidity.
The same is true for capillarization, i.e., increased signaling has been observed within hours, and increased capillarization in just a week or two.
ETA: The “father of exercise biochemistry”, John Holloszy, was of the opinion that such rapid adaptation was an evolutionary necessity. After all, a new predator or competitor for resources isn’t going to wait around while you get your act together.
Perfect, thank you! I could eat this stuff up and love learning about it. Obviously have a ways to go! 
Don’t try to talk to your hero. It’s guaranteed disappointment
always comparing to coggan lol … it has nothing to do with “sort of low tempo / high endurance” coggan ftp fail zones…
stop comparing it to other zone systems, this is based on metabolic events.
your real z2 can be walking pace. or it can be at a very high velocity close to your max. you can ride your coggan endurance or tempo but you probably far off of your real z2 …
and it is not connected to fatmax. even though for a majority there is a correlation. you have to look at lactate, substrate util and so on
How do you propose to look at substrate utilization?