That article discusses thermodynamic efficiency (already mentioned by @eduardo23), not “aerobic efficiency” as Altini defined it.
Interesting take on things. Thanks for that and makes sense. Now you need to consider your goals and which you think will benefit you the most and in what proportion.
My current understanding, which could be incorrect, is that there a couple of main benefits of long z2 rides: increased mitochondrial enzyme production that improves fat matabolism, and improvements to type IIa muscle fibers for aerobic use that requires type I fibers to be fatigued so the body with recruit additional motor units. I believe the type IIa fiber effects are more based on the number of contractions, not power or force output, so one needs to put in the time and pedal strokes to see the effect. That said, a common approach to do endurance work after interval sessions is partially to add volume / training stress and people often talk about the intervals ‘pre-fatiguing’ the fibers for the endurance part of the workout.
Maybe, but does anyone just do VO2max / anaerobic interval workouts? Do people, including myself, do those kinds of workouts? yes. Is it all we do? For most people I think not. At least I haven’t met any. Maybe in a spin class or peleton?
So if I walk 10,000 steps per day, I’ll train the type IIa fibers in my calves? Cool!
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To answer your question @old_but_not_dead_yet I don’t think it is a term that shows up in the literature (at least much, if at all). It’s a coaching term (maybe your point?). Basically one of several terms used to try to describe the relationship between power and HR by ppl who are not exercise physiologists.
Question for you, is the following better?
“Work Rate divided by Inferior Measure of Strain”
What’s wrong with power/HR?
This is a misleading comment. The study shows no statistically significant relation. If at all, mortality was lowered due to HIT training.
I think it would be a great idea if TR released a plan that was geared towards general well-being/ longevity, as opposed to optimizing for racing. As we are beginning to learn, the two approaches are dramatically different. Peter Attia often says that he is training for the “centenarian olympics,” not an Ironman.
For the time being, I think that the traditional base, as opposed to sweet spot base, training plan most closely approximates what you desire, @Thomas_Coury.
–Thomas K
So if aerobic efficiency is a term used in the popular press/coaching crowd, but doesn’t show up much in formal exercise physiology papers, the better way to communicate that would be to state it just like that. I find that exercise physiologists can come across much like engineers, who harbor their knowledge base with a little bit of attitude relative to people eager to learn. I don’t take it personally. It’s just kind of embedded in their nature.
That said, I appreciate all of the information from this discussion today. It has been super helpful. I’m happy others on this forum listen to Dr. Attia. I have my echo at the end of this month, and pending the results of that, will be crafting a more well-rounded exercise program for lifelong fitness. My days of trying to obtain Personal Bests as primary objectives are probably behind me. (BTW, I turn 43 this year.)
I’m not familiar with that term, instead I’ve seen these terms:
- Cycling Economy (Friel) and Cycling Efficiency (Coggan)
- Efficiency Factor (TrainingPeaks for Power:HR)
This might be of interest to you.
Huh?
As I said, high intensity exercise tends to be associated with lower all-cause mortality.
ETA: Actually, I didn’t. 
I see that I left out the word “lower”. Thanks for flagging my error.
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Agree.
I don’t understand the question. Perhaps I’m lacking context.
Probably. Not sure if it’s related to mitochondrial efficiency. Or just volume of time spent with elevated heart rate which would be unattainable if constantly doing intervals or higher intensity work.
Yes. Very probably. Probably more due to the fact that intensely-exercising populations are less likely to pay attention to or report chest pain with activity than non-exercising populations. A non-negligible chunk of the reversal of reduced mortality due to exercise once beyond X amount of time spent exercising weekly probably comes from athletes faulty assumptions that they are more healthy than they are. This is not to say that the physiological adaptations to high volumes of high-intensity exercise may not also cause very real, measurable increases in CV risk due to structural changes, at some level of exercise volume and intensity. I’m not well versed in those changes, their magnitude, frequency, or required exercise level to measure such changes, unfortunately.
Me too, in cycling. In running, swimming, etc., they need to use pace and lap speed, respectively as the numerator.
Aerobic efficiency is to Pw:Hr as Anaerobic Capacity is to Functional Reserve Capacity.
or General Sport Science Term vs. Sport-specific (or even study specific) measurement.
How many debates, discussions have we (not you and me, but the forum, community in general) had about the term anaerobic capacity? The reason is that it’s a loosely defined concept, not a measure or modeled value. The beauty of something like FRC (for example) is now you have a modeling thingie, so you either use it/like it, or you don’t. No debate about what it means 
It’s defined very clearly.
When you’re in the lab (and maybe not doing cycling) you might need a way to get at “work rate” (so power, pace, lap speed, etc.), objectively…power is power, pace is pace.etc. as it relates to physiological strain (the denominator). is this person nose-breathing at a certain rate, or on the limit? What about after training or a drug or some intervention? So in the lab they may use Pace / Some Input Calorimetry (gas exchange, cardiac output, respiration, lactate, RPE, combination of). The debate always centers around the validity of using one of these physical measures as the indicator of physiological cost. Like we do with heart rate.
Stress / Strain
Even though I’m replying to you @bbarrera this is just a general comment for anyone who cares, not really directed at you. I know you know.
Again, at least at the population level, it seems that the more (and harder) you exercise, the longer you live, at least on average.
As far as I am aware, the only established negative consequence of high volumes of endurance training is increased risk of afib, which in the big scheme of things is relatively benign.
Another recent study of exercise and mortality risk.
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Do you mean cycling mechanical efficiency? Power output divided by total energy expenditure?
I do recall reading somewhere that athletes who have the highest VO2max values usually don’t also have the highest mechanical efficiency. I’ll see if I can dig that up.
Not accusing you of drawing the following conclusion but cautioning others not to because I have seen it commonly even among researchers in exercise science.
Just because highest VO2max athletes don’t also have highest mechanical efficiencies does not mean there is a tradeoff in the attainment of both qualities simultaneously, but rather implies that elite outliers in each, don’t often overlap, which would be the probabilistic expectation. Overlapping extreme outlier characteristic odds are infinitesimal within one person.
Nature, nurture, or just a bad metabolic cart?
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Would people really pay every month for a “General well being, bike training plan?” Also how do you to test / verify improved general well being or longevity since that could vary so much from person to person?
I would also say there are a ton of apps that currently do that (remind you to drink water, track quality of sleep, remind you to walk every day, remind you to eat healthy ,etc.)… if it’s anything as intrusive as the app my health care company tries to use to incentivize you to stay healthy, I doubt people would come to TR to pay for that.
Also, that plan would probably mostly be "ride your bike at a moderate pace for 30 min to an hour at least 3 times a week, eat less junk and do some yoga occasionally.