75min Z2 enough?

@GoLongThenGoHome jinx! :joy:

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My take on it as well. If by doing it you are going some way to maintain your aerobic fitness then by definition you are not losing it which in its way is a gain.

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Exactly, and sometimes that’s exactly what you want (perhaps because you’re “progressing” something else). :+1:

Rats, of course. You’ll be hard-pressed to find comparable human data, though, so worth something.

I really want to see a study on this exact issue. Why is 3 hours the magic number, and is 3 hours in one to better than 5 hours cumulative over the week in 5x1hr sessions etc.

Also what about if I’m doing an interval set which lasts 2 hours. If I add one hour extra at Z1 do I get this magic 3 hour adaptation or not because it wasn’t all steady at Z1?

If 3 hours is the magic number then how many of these should you be doing a week to be a beast.

You hear it a lot about splitting up the Z1 long weekend ride if you can’t make time for one go. Is that really the same, sounds like a good one for the TR podcast though maybe it’s been covered.

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In a polarized plan, ANY work above Z1 means it wasn’t a Z1 ride. The idea is, for example, to do one REALLY hard ride, and then all the other rides for the week purely in Z1.

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Can it not simply be 80/20 time spent? You’re already out in the bike, nice to just add in some Z1 work after intervals. Pros do it too.

That’s not how polarized training is defined.

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You won’t find it, because it doesn’t exist.

Nobody in their right mind would attempt to do such a study in humans, because the external validity of the results would be meaningless.

About all that can really be said is that the fitter you are, the longer (or harder) you have to go to induce further improvements.

As other have pointed out, though, even if you don’t do that, at least you’re not taking time off, and going backwards as a result.

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I went back and listened to the Peter Attia podcast with ISM. Zone 2 is maximal stimulation of Type 1 muscle fibers, aka Fatmax, or LT1. Yes, you are correct. I’ve been doing my zone 2 rides below that and seen a significant increase in power for the same pulse.

5x1 hour isn’t the same as 5 hours as it is fatiguing the fibres that count…in the UK most of those in the know on the TT forum who know what they are talking about say that 4 hours is the “magic time” past which you start to get big benefits. That said, if you have only been doing 2 hours zone 2 then clearly 3 hours will become the magic time. However, I did loads of zone 2 in lockdown last year and found that knocking out 3 hour rides was easy, but no matter how many I did - about 50 odd last summer - when you got to about 4 hours it started feeling different and required more focus…anecdotal of course… :grinning:

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But wasn’t the context of ISM’s statement more on untrained/not sooo trained people? If I remember correctly

I know of no evidence that fatigue, per se, plays any role whatsoever in inducing the muscular adaptations to training.

Even the role of glycogen depletion is unclear.

I don’t spend my time combing the research but I know it worked for me which is all that really bothers me in the long run :grinning:

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Yes

Yes, He said for the vast majority of untrained people 1 hr of zone 2 (LT1) 3-5 times/week was sufficient to see improvement in mitochondrial function. He also noted that an elite level athlete may need 4 hrs to see improvement. So the target time frame is flexible. More is better, but benefit may occur at lower zones. He looks through the eyes of a physiologist, so without muscle biopsy, respiratory quotient measurement, lactate monitoring, you don’t know if you are optimizing this level of training.

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Can you please provide evidence for this?

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This? #85 - Iñigo San Millán, Ph.D.: Zone 2 Training and Metabolic Health - Peter Attia

I agree with this.

Last week I did (Seiler) Z1 rides of 3.5 hours, 5 hours 50 mins and 3.5 hours. The 3.5 hour rides feel easy. You don’t get hungry, no need to eat. As the duration stretches out you do get that fatigue and it becomes harder because of duration not intensity.

The 3.5 hour ride in Z1 will initially feel hard but you will get to the point, as you say, where you can just knock them out. Then increase the duration again and you push the endurance further out.

My minimum event duration is between 9-10 hours and stretches out to over 4,5,6, 7 day single stage events. You know the ultra endurance ones 2,000km and up.

I’m no physiology scientist. I’m not aware of anyone here who claims they are. I’ve read the stuff just like others. My experience says that the long Z1 rides are driving three key benefits for me.

  1. Fatigue resistance. I can go for longer and longer durations without deterioration. I stay fresh over increasing distance.
  2. Food intake. I’m quite happy on 20-25g of carbs per hour for many many hours. That’s a couple of short bread fingers per hour. Very manageable over long distances and durations.
  3. My speed at low intensity over long distances is increasing year on year.

For the multi day events this means a little snacking every hour and then more substantial meals at more traditional meal times.

The only explanation, unless anyone has another, is that the amount of energy I can generate from my fat stores is significantly uprated. I have never managed to get into this conditioning from shorter and higher intensity training.

So I’m a big fan of polarized for ultra endurance events. If someone does shorter punchier rides , maybe it is not for them.

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In your case, specificity of training and mitochondrial adaptation happily coincide. :slightly_smiling_face: