Long slow endurance for mitochondria building

Hi all,
My understanding of studies into this is that to increase the number of mitochondria, you need to do 2+ hour rides at under 70% of MHR. Is there another way of achieving the same thing on shorter rides and if so how?

Intensity seems to be a more important driver of mitochondrial biogenesis than duration.


What that study shows is that fast twitch(white) fibers respond to intensity but slow twitch(red) fibers only respond up to a certain level. Since it was approximately work matched we also don’t know if the duration is increased substantially if the magnitude of mitochondrial biogenesis will be greater even if the signalling is lower


I half jokingly told a poster that asked this question that the minimum was 2.5hrs.

I got scoffed at, mocked, and harrumphed for my “references” about the time required for these changes.

I’ve seen the error of my ways by the classy denizens of our little inclusive forum. So, now?..Well I’m sure 15 minutes of Z2 at a time every third day will bring about the mitochondrial changes you’re seeking.

Good luck!


I thought it was 3+ hours. I’m going to change my plan to just 15 mins 2-3 times a week instead of having a nice long ride on weekend. :wink:


To the topic:
As much as we are told every once in a while and with every new study that the way we used to do our streching (long and steady, or bouncy and quick) was completely wrong before, the same way you can find arguments pro this and pro that, contra this and contra that. Eventually it is anyway a question of time constraints, individual physiology etc. We are just amateurs trying to squeeze sports into our daily lifes… ride as much as you can and enjoy … and this will bring you loads of positive results for sure. Dont be disguised by all these studies and discussions.

Absolutely sharing your sentiment. It is almost ridiculous how picky so many here are about all this … eventually most of us are average joes being misguided by some imaginary numbers which almost none of us have the proper means to measure precisely and reliably on the long run, and much less would we be able to compare these numbers in a forum, where none of us know each other personally, probably none of us share the same equipment so that results could be compared to each other… and none of us bring the same physiology, the same available time, the same amount of stress/non-stress to the table… so many things have influence on our results. food, time, stress, sleep…etc. how can anybody here really claim to know the absolute truth for something which is mostly just a hobby for the biggest part of TR users.

all of these talks are very much just for the sake of discussing and being right.
I am getting more and more frustrated by this.

Ending OT. sorry.


Are you solely interested in mitochondria, or is it a means to an end?

My non-scientific pithy answer is: ride as long as time allows, but know that every little helps.

There are no such thing as junk miles when it comes to endurance sport.


Increasing the mitochondria is one thing but maintaining the number is an other challenge:

And nice listen from D.Bishop:

And longer article from him about mitochondria:


Why did you include three reputable sources in your post?

I thought it was enough just to whine about something someone wrote in the past that got backlash in the forum :wink:


Because I am not a reputable source mysfelf :slight_smile:
Basically, there are two things - what you should do and why something happens. The more I read from here and other sources training as a “idea” is extremely easy - do the highest volume you can, introduce some intensity. Do some moderate intensity and some high intensity and supplement it with long Z2 rides, rest a lot and eat a lot. No matter what training principle you apply, it always works the same.

Why something happens - this is the other thing and probably there are no “clear” answers for anything. I am far from fetching the latest research and introduce it to my training when I know I must work on my basics. Sometimes I have a feeling it is like arguing how fast and aero is the Trek Madone vs Aeroad vs Tarmac SL7 when it does not matter for us, mere mortals and as we see does not matter for the professionals. The more I observe many differtent fields the more I see the people “on the top” are the least interested in details and more focused on basics.


I just had to quote that, great summary!

The problem is people want shortcuts.


The reason that adaptation in ST plateaued was due to changes in recruitment.

Other studies have shown that increasing duration beyond 2 hours at a constant intensity results in little if any further increase in mitochondria.

In any case, it is clear that contrary to the OP’s original statement, you don’t have to train for 2 hours before things “kick in”.


For context:

You’ll only need to devote 12 minutes, but you’ll have to go a lot harder than zone 2.


@Bardia Welcome to the community! (I think)

Almost all forms of endurance training will increase or maintain the same level of mitochondria.

I think the reason you are getting some of the responses you are getting is because there really is no definitive way to answer your question. We can confidently say that a well-designed training plan that you stick to and can maintain for months and years will lead to lots of physiological adaptations, including mitochondrial biogenesis (among several others…not sure why all of a sudden the mitochondrial adaptations became such a hot topic, it’s not the only thing that happens. Why just have one improvement? I want them all).

  1. Get a coach*
  2. Try a TrainerRoad plan

(those are not the same thing, but either can work)

*Over the last two years (since the forum’s inception from FB), the questions that draw the most—let’s call it debate:slight_smile: are simply variations on “Hey guys, please give me some coaching advice”. That’s fine, but you need be able to filter the signal through the noise, and have a pretty thick skin.


I think I posted this in the other thread as well, but whenever someone asks ‘will X work?’ or is Y enough?’, the answer is almost always ‘for what and for whom?’

If you’re a pro with an FTP of 6w/kg then my (totally non scientific) thought is that 2hrs at 0.7IF is probably not going to drive much adaptation. If you’re straight off the coach, then literally 20 minutes at 0.6 is going to have a training benefit.

It’s always about the SAID principle at the end of the day.

Now factor in time availability for most of us, and the answer to the original question gets even more ‘it depends’.


Mr. Dylan Johnson just showed off his monster base season with 30hr weeks. Apt for this thread. Cheers. H

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Ouch. Over the top with the haymaker.

I has sad

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what studies?

You’re a good sport! cheers

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