I may be wrong here, but I think mitochondria development is influenced by intensity – more at lower intensities and less (moving to muscular development and lactic response/shuttling) at higher intensities.

It’s how I’d understood some of the articles on Joe Friel’s blog at a basic level – Z2 pace being most effective for that. The analogy was something like boring out the engine first then tuning the increased capacity.

Going back to Dr ISM, I think the difference is in the type of transporters you promote. With high intensity work- you build the MCT 1’s which are designed to rapidly move lactate out of muscle cells and into the blood.
With low intensity work, you build the MCT 4’s which encourage lactate from your fast twitch fibres to be used as a fuel by the adjacent slow twitch fibres.

That’s getting way beyond my GCSE Biology knowledge but makes sense.

Just playing it out to help my understanding-
Someone with a Zwift racing, chainganging, Sufferfesting, Peleton or other HIIT type bump in performance gets good at shuttling lactate into the blood via MCT1.
Someone with a large base in contrast, can actually use a lot of the lactate as fuel via MCT4, thus keep their blood lactate lower for longer and likely do harder efforts after a couple of hours than the HIIT rider.

This would also explain how periodisation works. You build a big foundation of MCT 4 and then as you approach your A race, you let that pathway plateau/decay slightly and fire up some MCT 1’s.

For me, the ‘increase mitochondria’ is the main point of the Z2*, not weight loss or becoming fat adapted

Well the weight loss comes from the fact you can and are doing much more of it. You may burn 30% more calories per hour doing high intensity work but you can do (say) 400% more low intensity without becoming fatigued, so the overall calorie output is much greater.

I drop weight more noticeably when I’m doing a weekly threshold session among my other riding, 20-25mins in total at LT. Feel like that revs up my metabolism more or for longer overall.

There are many articles saying that high intensity work is better for weight loss, but I am not sure this is the case for everyone. If I do high intensity stuff or even weights I rapidly get fitter and/or stronger but I don’t lose weight because my appetite goes through the roof, and if I don’t eat enough I don’t recover. I think that the balance of hormones produced by an individual in response to training load varies a lot, and how the individual then responds to those hormones also varies.

Last winter I did two Zwift races a week; this time I am doing only one and trying to do Zone Netflix the rest of the time. The z2 has definitely helped loads with endurance, as I went flat out on Tuesday and wasn’t tired the next day; but I was very hungry and ended up eating more carbs than I was planning (although I kept it healthy). If I only do z2 then I don’t experience the hunger.

You may burn 30% more calories per hour doing high intensity work but you can do (say) 400% more low intensity without becoming fatigued, so the overall calorie output is much greater.

I read something about HI work raising your metabolism significantly for a number of hours afterwards, much more so than Z2.
I might just burn more calories at + after HI because I’m less adapted to it Vs Z2.

jameso

I read something about HI work raising your metabolism significantly for a number of hours afterwards, much more so than Z2.
I might just burn more calories at + after HI because I’m less adapted to it Vs Z2.

There was a health/fitness/weight loss program on a few years ago where they talked about this. It might have been that Michael Mosely bloke.
He did a run hooked up to lab equipment that measured exactly how many calories he’d used during a run on a treadmill.
They then looked at his metabolism over the next 24hours (might have been longer, actually) and found that it was raised for a significant time after the exercise. I think he burned something silly like 3x more calories (above base load) in the 24 hours after the run, than he did during the actual run.

Which is also why you are still fatigued if you try and do too much consecutive HIIT 😃

Z2 is about consistency too. My upper Z2 calories are over 800/Hr now. And I can do that again tomorrow.

If I zwift race for an hourx, even at 1100kcals, I’m already behind 90 mins of z2.

That’s a lot. I’d say 6-8hrs a week is enough to have a really big impact for a recreational cyclist especially if you have never done it before. However, if you feel like it then go for it as long as your body can take it. You might find your knees get a bit sore riding on a trainer that long.

Well looking at my available time and schedule clashes I would hopefully (initially at least) try to squeeze in 3x2hrs (maybe 2×2 + 1×3) between Monday and Friday, alternate evenings makes sense but I may need to be flexible, I’ve got the time and it would beat sitting on my arse in front of the TV or ducking out of night rides because it’s a bit too wet.
I will still manage to do 1 or 2 commutes each week as an alternative, but I’ll try to keep those similarly low ‘n’ slow efforts to contribute to my Z2 volume…

Then at the weekends more intensity can creep in. I was also going to do the odd 5k trail run from my doorstep, I’d been doing that before Xmas but slacked off, and get in at least one 2-4hr Road/Gravel ride that can be more Z3+. I’ll try to stick to that at least until the weather and sunlight picks up around March (fingers crossed).

I hesitate to use the term “Base miles” but it feels like that’s what I’m heading towards with a large volume of Z2, Meh…

I had also been doing some 3x20min “threshold” sessions on the trainer to try and build capacity but TBH I may as well go for a run to mix things up and going for Hard, short sessions indoors wasn’t really helping manage weight. Running seems better, hopefully large Vol Z2 will contribute along with cutting back on the bread (I do love toast and sandwiches)…

I’ll call it a loose “Plan” for now (same as every January) and see how I’m going after a month, that’s about the level of “training plan” I can manage and adhere to I think, it will require review by mid Feb no doubt.

Well I attempted a ~50min “Z2 commute” in this morning and managed to keep under Z2 for roughly ~50% of the ride (My watch gives a ‘time in zone’ breakdown of an activity which is handy), my Avg HR is nicely in the middle of my Z2 range, but it was suprisingly hard to manage my effort down, climbs would push me over then there were plenty of flat sections directly into a head wind. All while being buzzed by cars… I don’t think trying to manage HR down works on my way to work.

At one point I was pedalling along and got a series of alerts and chirps as I topped out of Z2 and then dropped back in.
Riding home should be easier to maintain more time in Z2, all the climbs become descents and that headwind will be a tailwind (hopefully).

Obviously a fully Z2 ride is pretty much impossible unless you live in a traffic free, pancake flat wasteland but what percentage of your time on the bike (as opposed to a trainer) would you hope to be in Z2 if targeting?

I think I may be spending more time on a trainer as part of this little experiment…

I did 2hrs outdoors on Tuesday. Rolling hills.
And managed 72% Z2/Z1 by power or 87% Z2 HR.

I did 2hrs indoors yesterday and it was 91% Z2 HR.

Just ride to HR/the talk test outdoors and let the watts fall where they may.

2 and half hours outdoors for me last night, just riding on feel and occasionally glancing at HR which never went above Z2

82.6% Z1/Z2 I never worry about straying as long as it’s not sustained and the HR stays below LT1

Sunday Dyfi
Monday raced
Tues raced
Thurs raced

😉

The only reason i had a HRM/power is because you need to for racing….

you’re all bonkers 😀

2hrs 20 mins tomorrow on Zwift Flanders Endurance ride at 08:30, feel free to join in 😀

Z2 dog walk at 8am

you’re all bonkers

Did you win your race?

If not, you would have been beaten by people who probably are also bonkers…

If not, you would have been beaten by people who probably are also bonkers…

I’m ok with being beaten 🙂 I came to terms with that a long long time ago

As mentioned elsewhere, I’m not taking OTT training Jibes from someone who owns a shockwiz 🤣🤣

You’ll be going to a skills coach next 😉

Sunday Dyfi
Monday raced
Tues raced
Thurs raced

😉

The only reason i had a HRM/power is because you need to for racing….

you’re all bonkers 😀

I do like reading about yours and Weeksy Jnrs adventures but we’ve all got different lifestyles, free time and resources available.

If I had to keep up with a super keen teenager and had the spare time and cash as you seemingly do, I probably wouldn’t be mulling such mundane things as how to do a bit of “structured HR based training” between work and family commitments.

I’ve no doubt you’re substantially fitter than me, we all know you get the turns in, but I’d rather not be belittled by someone just because life has handed them a couple more opportunities to spend more time doing something they enjoy. It’s great you’ve got a ready-made riding buddy, spare time and sufficient funds to live the lifestyle, But try not to bend rule 1.

Quick question, this is purely theoretical as I am an avid non trainer who just likes riding bikes…are those quoting the gospel according to zone 2 telling me that if I went out and did 2 hours zone 2 followed by riding about how I want to for an hour it would mean less mitochondrial recruitment than just riding zone 2. I understand crosshairs desire for volume to aid weight loss hypothesis but not this.

the grown-ups will be along once they’ve finished their 5hr spins 😉

I *THINK* that the theory goes that stressing the “low end” system can only be done at Z2 (or lower but that’d not be maximal).  Once you step above that, the high end system kicks in and stays “on” for half an hour or so and overrides the low end, regardless of how you then ride duribg that half hour.

… so I’m saying you’d get essentially all the benefit of yr first 2hr IF you stayed out of thehigher zones for all of that period, however you bugger about afterwards but you have to be strict for that first part

(IANISM)

If you’re looking to be better at endurance riding then being efficient at burning calories is a benefit but this is opposite if you’re looking to lose weight.

the grown-ups will be along once they’ve finished their 5hr spins

Morning! 😀

I drop weight more noticeably when I’m doing a weekly threshold session among my other riding, 20-25mins in total at LT. Feel like that revs up my metabolism more or for longer overall.

Calories in vs Calories out is the same whatever zone you are riding, and leaving a deficit will result in weight loss. But one warning here if you see immediate weight loss – average body stores 400-600g of glycogen, and each gram of glycogen attracts 3-4g of water. Therefore depleting your stores will show some pretty rapid weight loss, but it wont be “real” and as you restore it / rehydrate you’re likely to see a swing in weight. This is one of the reasons worrying about daily weigh-ins is pointless and you should track weight consistently over a long period e.g. weekly weigh ins at the same time once a week for 3 months.

FWIW, I did my 2:20 today with an average of 194w, 1565cals burned. The trick now after lunch is to not react to hunger with anything other than a small protien snack until dinner time and leave some deficit on the table!

FWIW, I did my 2:20 today with an average of 194w, 1565cals burned.

I went for a ride of just under 3 hours!!!

Yeah, more z2 trumps less z2 but 2hrs Z2 and then….. is still better than 3hrs of mixed up stuff. Basically it can take 20mins after a burst of intensity to settle back into <LT1/VT1/fat max etc etc.

First z2 ride of my polarized plan tonight, 1.5hrs after being off the bike for 8 weeks.

I’m still wrestling with my I get more back pain for Z2/winter riding. I’m pretty sure it’s an intensity/muscle recruitment thing (I don’t believe theories about being cold as I usually dress pretty toasty).

I mucked about the other day pushing a lower cadence which feels easier recruiting glutes etc. but I understand lower cadences are less useful in Z2 as they recruit more fast twitch muscles. Problem is lower cadence does seem to make my back happier, which possibly explains why I usually feel better for riding gravel/CX than I do for riding easy road, it’s impossible to spin a fast/smooth cadence constantly on the gravel bike in the mud!

So I guess I need to do a lot more gym work to achieve better core endurance/stability whilst twiddling easy gears in Z2 for hours on end.

Or just go back to plan A and smash around any old how and do sweetspot sessions on the turbo instead of Z2 😎

I’m pretty sure it’s an intensity/muscle recruitment thing (I don’t believe theories about being cold as I usually dress pretty toasty).

Though I’ve been the opposite to this,

Problem is lower cadence does seem to make my back happier,

usually a masher not a spinner and low cadence causes back tension in the last year or so,
Have you tried a kettlebell?
You mentioned muscle use and one thing I’ve learned in recent weeks is how hard kettlebell swings work the lower central back, the glutes and muscles along the rear of the thighs. So much so that I’ve been climbing in Z2 at 30rpm again, a strength builder I’ve not been able to do for some time due to back tension issues. It feels like I’m using certain leg muscles more, like the kettlebell has engaged muscles that desk jockying may have weakened – but that’s a ‘feels like’ not anything credible. It’ll largely be a bit of localised muscle soreness meaning I notice that area when pedalling. Anyway, combined with basic daily hamstring and quad stretches it all seems to be adding up well. I’m very gym-shirky and CBA with 30min + periods of reps etc but the kettlebell is great for easy fast results.

Basically it can take 20mins after a burst of intensity to settle back into <LT1/VT1/fat max etc etc.

What counts as a ‘burst of intensity’ here?

My upper Z2 limit is around 133 to 135bpm. I might go to 140-142bpm on a climb but I’ll back off or even stop as soon as I feel my HR rising and I know my effort levels well enough that I’d rarely go over 140 before backing off. So it may be over 135 for 10-15 seconds, rarely 30 seconds, it drops back pretty fast these days.

Currently doing the Gran Fondo Plan on Zwift. I have this scheduled for the weekend:

Gran Fondo Wk 6 Long Ride

I’m happy with the duration but wondered what the point of the warm up and 5 min SS blocks is. As I understand it, the warm up will just deplete glycogen stores and train muscles to go there rather than burn fat. Given that the actual Zone 2 blocks are 25 mins and it can take 20 mins to settle back to LT1 etc, I’m unsure of its purpose.

You mentioned muscle use and one thing I’ve learned in recent weeks is how hard kettlebell swings work the lower central back, the glutes and muscles along the rear of the thighs.

Yeah, I need to work up to these big sort of exercises, I’ve learned how twitchy my back muscles are in general so kettle bell swings give me the absolute fear! As an example, my lats are one sneeze away from spasm at the moment because I went too hard with some gym ball dead bugs! (squeezing the gym ball between knee and forearm whilst engaging hip flexors/TVA).

I’m building up to bigger low back moves with lots of supermen/low back extensions on the gym ball though.

The only reason I bring the back pain thing up in a Z2 thread is because it seems more of an issue the easier I go on the bike 🙄

Given that the actual Zone 2 blocks are 25 mins and it can take 20 mins to settle back to LT1 etc, I’m unsure of its purpose.

Yeah, I would question the purpose of going beyond Z2 in a warm-up if the session is Z2! I guess you could get away with extremely short bursts but it still begs the question why?

I warm up for Z2 sessions by just very gradually ramping up, although pertinent to my issues with back pain (above) I do now try to do some activation type stuff before the workout

https://cinchcycling.cc/blogs/news/how-to-prevent-back-pain-when-cycling

So many Zwift workouts have “pointless” variations in effort as regards training, in an attempt to prevent the average user not dying of boredom.

Ive been off the bike for a while, and any exercise since before Christmas so started doing some Zone 2 stuff on Rouvy. I find it ok riding round something like Lake Garda, stuff to look at, slight changes in incline etc. Bloody hard not to respond to people coming past though ! I just have iPlayer as a bit of distraction.

According to Strava though on a 1hr ride I am only averaging ~ 115W !

So many Zwift workouts have “pointless” variations in effort as regards training, in an attempt to prevent the average user not dying of boredom

So true. They’ve recently increased the number of ~30 min workouts which for most serious cyclings, investing proper money in a turbo etc, are completely worthless. Suspect I might be better trying to mimic a TrainerRoad Zone 2 workout.

Ref: Back pain. Mine flares up with real life steep climbing i.e. forceful, low cadence stuff. My only issue with Zone 2 is a numb backside as you’re putting far less force through the pedals and all your bodyweight on the saddle.

Just stealing this from the TrainerRoad cycling memes and joses forum thread.

Speaking of San Millan here is another video on “Zone 2 and beyond”

I’ve been doing about 4 weeks now of Zone 2 after reading some of this and watching a GCN thing.

I use Rouvy, which has some options of fairly flat rides with vaguely interesting scenery. The max Ive done so far is about 1hr 15. After that Ive had enough as bum going numb from being in the saddle so long, and well its being on a bike in the garage.

I am really enjoying the benefits. I’ve lost weight and I am not as tired and my legs are not as tired. Its translated to better fitness off the bike running too.

I am not looking at racing or doing any events this coming year so happy just to build my fitness slowly.

@jamesso

I think it’s important to look at all of this stuff through squinted eyes a bit.

The second GCN interview with ISM clarifies the ‘little bit of intensity’ question. ISM himself says that going above z2 on a hill, or pulling away from a stop, or the occasional jump on intensity really isn’t going to make a huge difference unless it results in lactate production that doesn’t disappate pretty quickly. You don’t have to be a metronome – but the more metronomic you are the better. So banging out a best effort 5min vo2 Kom is going to have you burning glycogen for a while to recover. Getting around a car for 15s at vo2 power is not.

A good analogue is – did the effort functionality change how your RPE – in terms of breath becoming more laboured etc, or make it harder following the effort to stick at that good z2 pace. If so, problematic. If not, fine.

You don’t need to stare at your head unit to make sure you’re +/- 2W whilst accelerating from a stop sign.

^ thanks – I was meaning to come back to my Q here,

What counts as a ‘burst of intensity’

I watched that GCN episode with Inigo San Millan the other night which answered it well, as well as made me think my (trad from % HR max and LTHR) Z2 upper limit is a bit low. Going over it to 140-145 is fine as I can still talk+chat at that pace, just a few added pauses.
From the other episode with the presenter finding his Z2 on the test rig I understood that flat-ish spot then ramp up feeling.

Z2 rides just got a bit more fun and quicker, more useful perhaps, good stuff.

The episodes also got onto how slow twitch muscles don’t produce lactate and I expect I’ve done a lot of work on those muscles over the last 10 yrs or so – long steady miles, low RPM low HR climbing, SSing etc and generally having a low cadence on the bike. Very little on the fast twitch apart from general MTBing. But I don’t get anywhere near the amount of leg acid burn as I used to when working at my max sustainable 5-10 min climbing pace, which I took to be age and lack of ability to work the muscles hard. Seems there more to it than that. My sprint is fairly hopeless but I’ll take that as a fair flipside to the gain in endurance and ability to hold a pace.

Just reading your post @FunkyDunc made me think it’s worth reminding everyone that there are “Riders choice” workouts in Zwift (everyone gets 25Km free per calendar month, ride on Ven Top that is hilly from start and you will get more time for your 25Km distance 😉 ), which allow you to ride any route and not get the normal extra resistance for climbing hills.

Your gear selection and cadence decides your power output, not the terrain.

I’m sure there are several duration lengths of this “workout,” but one is found in https://whatsonzwift.com/workouts/60-90-minutes-to-burn/90min-riders-choice

I’ve more or less been doing just base work since October now 🤣 First under/un fuelled for weight loss and then since Xmas as part of a plan inspired by Friel’s book.
I’ve added on some Tempo progression now as part of Base 2- as I want to try for 2h at 300w this summer.
This isn’t really a Friel workout but kind of fits with his M1 or maybe AE3 from the workout menu.
Last week was 1×120 @ 250 and this afternoon was 1×120 @ 260.

I felt amazing today! Ended up on 2h outdoors in the sun at 263w average. Even better, HR was just 158bpm which is only really one bpm into Tempo! So I reckon the top of my Z2 is definitely at least 250w now.

This highlights the flaw with FTP based zones as I really doubt my FTP would test at 333w (which it would need to be for 75% to equal 250w).

I’m almost looking forward to Chainy season now to see if it actually translates into better performance. (And how everyone else stacks up after a variety of approaches to winter)