[Closed] Zone 2 Training (yawn...)

What's your max? Have you tested it?

How did you work out your zones?

FWIW my (lab tested) zone 2 changed from training

125 - 144 to 140 - 158

Zone 2 you should be able to hold a conversation fairly easily

I rode in at what I think zone 2 is today, under 130 (max HR is 186), it took 54 minutes. The fastet I've done is 42. So yes well slow.!

If you don't do some recovery level or base level training you will burn out / plateu or get fat is my thinking

Try this

http://www.machinehead-software.co.uk/bike/heart_rate/heart_rate_zone_calculator_abcc_bcf.html

It was set by the Garmin, then I used an internet calculator for the zones (based on age, weight, activity levels etc. Base was 5 x checking pulse through the day at states of rest, then average at 58bpm. Max is 186, again from the internet.

I could indeed hold a conversation. I did my usual (MTB) training ride as usual pace and found I'm pretty much always in zone 3.5 to 4.3.

Obviously zone 2 on the road would be faster, but probably way below the 17mph average (for 50 & 70ks) I have been riding. The 100k I was planning would take ages!

Zone 2

It is important to note that when out on the open road you may find on hills etc that your heart rate goes out of this zone. It is important to avoid this happening. You may think after uphill sections you can recover back into zone 2 and burn fat again but that’s not the case.

Once your heart rate has gone up your body will kick into sugar burning mode and it can take over 30 minutes to get back to fat burning so the training session can be wasted. 80% of your cardiovascular training should be spent in this zone.

This may seem a little easy and hard to keep to, but the main thing is to be aware of not spending too much time out of this zone. Over time this zone will increase to a level (in terms of heart rate and power output) where you still use fat as an energy source.

TD - I used exactly that yesterday 🙂 and thanks for the text that confirms what I thought. Its a matter of training correctly but I'm going to find this hard indeed....

Obviously zone 2 on the road would be faster, but probably way below the 17mph average (for 50 & 70ks) I have been riding. The 100k I was planning would take ages!

But you wouldn't be riding it in zone 2. Base training is the foundation of aerobic training where you train your body to utilise fat as an energy source

Eh? I ant to train in Zone 2 for exactly the reasons you mention and build slow twitch endurance - why wouldnt I ride my 100k in Zone 2 - are you suggesting just do a shorter ride? Does that still have the same effect?

. The 100k I was planning would take ages!

I assumed you were talking about riding in zone 2 for the whole of the 100k challenge you were training for.

Sorry.., yes if training in zone 2

Ah yes - training only. The roadie (atm) is a training bike for MTB. I ride 3 x per week - once on the roadie. I'm trying to stretch my distances. At the age of 39 despite riding MTB's for 10 years (socially) I'm about 3 months in to road riding once per week after racing the MTB's this year and wanting to continue with that. I've basically just been riding as fast as I feel comfortable at 50k, then the last 2 rides have been 70k and now I have a 100k planned.

I'm usual Joe Friels book to train to, but this is the first time I've used the HRM. I might then, first try a 50 at Zone 2 otherwise I'm likely to be out for more time than Mrs Kryton would be happy with.... :-/

Cheers for the assist.

Tricky, when you had you zones calculated, were they based on 5 or 6 zones as depending on which you go for it throws up different figures.

I've gad a look at your zone link but there's also this one. [url= http://www.brianmac.co.uk/hrm1.htm ]Clicky[/url]. There's a link about 2/3 of the way down which gives you a 5 zone chart.

How were you feeling today, not got a cold or anything.

I have been training in Z2 (Don Fink) so maybe a bit different to yours. Did 110m on the road a couple of weeks ago in Z2 and averaged 17mph.

Week after I had a bit of a cold and on similar terrain averaged 15mph over 40m in Z2.

Just a thought

When you say max is 186, have you done this through a self test or by a formula?

I was given a 5 zone chart from my fitness test. I'm not sure it matters how many zones but to work consistently.

The coach doing our weekly turbo sessions uses 6 but i think that's too much

opps, ignore.

Some of that text strikes me as a bit misleading, zones are not step changes, you don't suddenly go from 'fat burning' to ''sugar burning' over a 1bpm increase, so I'm not sure about this "30 minutes to get back to fat burning" melodrama!

Using zones from an estimated max HR may well be totally pointless. Do a max HR test. To be honest, riding absolutely flat out up a big hill will give you a reasonable idea. If you're feeling sick and seeing stars and doing 170bpm (or 200bpm) you'll want to recalculate your zones!

I use HRM and turbo during winter and for some interval training all year round For a reality check wear your HRM say at local trail centre and record your time and zones. My HR for the black at Afan are nearly all 4 and 5. Little or nothing in Z2. My maximum and rest have been tested professionally so I know Im set up correctly. Point is that for MTB you do need endurance but that could mean using Z4 and Z5 for say a 4 – 5 hour enduro. I tend to just use Z2 for recovery but most of my 3 - 4 turbos per week this time of year are aimed at developing my threshold. I will add distance when the weather warms up 🙂 Just dont be too fixated on long slow. Whats your goal? Adapt your training to your goal. Lots of Z2 may well have a negative affect on top speed or burst power up a steep incline.

I think more in terms of training that brings about an adaption of my VO2 that raises my lactic threshold. So on an enduro I may be in zone 2 but they may well allow me to maintain a lot higher speed/effort than others. One persons threshold isnt the same as the next and its that threshold that defines your ultimate endurance. The higher the better. The change from fat to sugar burning is gradual and this explains why very fit people need less water and food during events as they simply dont burn it up at the same rate as a less fit person for a given speed/effort.

Sorry for rambling but wanted to make sure you noted the plus and minus of long and slow training and alternatives approaches

A couple of other ways to calculate MHR. [url= http://www.timetrialtraining.co.uk/S6MaxHeartRateTests.htm ]Link[/url]

ome of that text strikes me as a bit misleading, zones are not step changes, you don't suddenly go from 'fat burning' to ''sugar burning' over a 1bpm increase, so I'm not sure about this "30 minutes to get back to fat burning" melodrama!

To be fair it was taken out of context of a full report i had. The chart showed a gradual decline of using fat as an energy source as my hr went up..

it's not about miles it's about hours. zone-2 is best done for longer blocks, if you are after winter base miles to increase endurance then half an hour commute isn't enough. no idea what miles i'm doing but i try to do 1-2-3 hr blocks.
don't use a HRM just go on breathing/perceived effort or ride with others with the same training agenda, sticking to the inner ring helps too.

As for goals, I just want to be fitter and faster. I have limited time (work, family etc) and am never going to be on a podium, but it'd be nice to being doing well generally for events such as 50k's, posting good lap times at things like SITS/Bonty 12, and generally trying to achieve that via the 3 rides a week I can manage consistently.

As some kind of indication - confirms with Pawsy's info - I did a 31k training mtb ride today, with the following stats:

Average speed 11.9mph
Average HR zone 3.9 (85% max) 158bpm
Max HR zone 5.6 180bpm

I'd really like to be riding at 12.5 -13mph average in 2012 on the same course.

Useful input everyone, thanks. - Good tip about limiting the road bike to the inner ring.

Zone 2 is a happy place

zone-2 is best done for longer blocks, if you are after winter base miles to increase endurance then half an hour commute isn't enough. no idea what miles i'm doing but i try to do 1-2-3 hr blocks.

Nearly all my 'base' training/zone 2 was done at 1hr at a time max last year (indoors).

it's not about miles it's about hours. zone-2 is best done for longer blocks, if you are after winter base miles to increase endurance then half an hour commute isn't enough.

i was under the impression that base was cumulative & could be done on several 1 hour commutes a week.

happy to be corrected.

i was under the impression that base was cumulative & could be done on several 1 hour commutes a week.

happy to be corrected.

if you commute every day (and ride at the weekend) then there is no recovery (or active recovery) if you could take the commute hours and do them in longer blocks with a rest day in between then you would be better off. life doesn't always allow that though 🙂

I'm only really spending much time in zone 2 on "recreational" road rides where I'm working but not hard. If I'm going out to push myself, zone 2 is as low as it gets and I keep myself somewhere in low-mid zone 3 for most of the ride. But usually that sort of ride is the once a week longer ride 40-50 miles so it's not like I need to conserve energy for the way home, following day etc.

If you've been using Joe Friel's books then you'll be aware that he doesn't advocate using MHR as a basis for establishing training zones - he works on LT (lactate threshold). He also shows you how to calculate it using a 30 min time trial - ride flat out for 30 mins & start the HRM for the final 20 mins (once your HR has settled in). Your average heart rate for the 20 mins will be very close to your LT.

+1 atlaz

+1 for LT its the way forward

I find it difficult to get a good training session in on the road except. Stopping for traffic and cold. Happy to put the telly on and spin away 🙂 yes the turbo is in the living room shocker 🙂

If you've been using Joe Friel's books then you'll be aware that he doesn't advocate using MHR as a basis for establishing training zones - he works on LT (lactate threshold). He also shows you how to calculate it using a 30 min time trial - ride flat out for 30 mins & start the HRM for the final 20 mins (once your HR has settled in). Your average heart rate for the 20 mins will be very close to your LT.

Indeed - I intend to try that this weekend, although finding 30 minutes / 10 miles of flat isnt easy. There is a midway section of a 50k look I have which is a gradual rise to a gradual down back to the same point which is approx 10 miles so I'm going to use that as my measure.

I'll then adjust the zones according to the scale in Joe's book.

I've ordered Joe Friel's book too and should be here today, so I'll be doing the same thing. I'll be using a turbo trainer though.

Need to fit in a 2/3 hour Z2 ride as well.

I've ordered Joe Friel's book too and should be here today, so I'll be doing the same thing. I'll be using a turbo trainer though.

Need to fit in a 2/3 hour Z2 ride as well.

Once you've read it, I'd be interested in your opinion of "overtraining" and "overliving" version the "One to two rides per day" suggestion.

I think I'm struggle with the difference between amateur and pro in Joe's book - I think the only flaw to the book (it is very very good IMO), is that is doesnt distinguish a line between those two points - its very grey.

I'd imagine if you're not used to a high frequency the 2 rides a day wouldn't be advisable.

I've used the book as a basis for a plan for the past few years and have felt the benefit, esecially the Z2 training in the winter.

I read that book this time last year and mapped out my season using the blocks of training weeks that were recommended.

Its an interesting and helpful book for those looking for a thorough introduction to creating a training plan.

Once I planned my sessions I stuck to the schedule roughly 80% of the time, but found I needed to simply get out and ride every so often to remind myself why I cycle.

I got myself tested in Jan this year and again last month, the increase in fitness, (in watts/kg at threshold), has been considerable, so it clearly works if you put the effort in.

I'll make some adjustments based on my experiences and use the same formula again this year.

So I'm also trying to keep it aerobic at the moment. Got HRM but using the old if you can breath through your nose, you're aerobic.

Thing is, one session on the turbo I'll be 165ish bpm at the upper end of aerobic and then the next session I may be around 175bpm.

I know that HRM is not an exact science, but can ones HR be that different one session from the next?

Oh the HR monitor is a garmin... distances,times and average speed stay pretty constant.

Its also worth noting perceived effort as well as HR. The book talks about calculating the weeks effort and using that number as a gauge to make sure you're training consistently, (Think it was perceived effort of each session time training time in minutes, but I'm not sure off hand)

10BPM is not much, but certainly enough to push over into the next zone. What you ate, drank, how you slept, if you're stressed all potentially alter your HR. What you should do is reduce the effort until your HR falls into the desired zone, otherwise what the point of using an HR?

I hardly ever prescribe what the OP refers to as zone 2. IME it's an utter waste of time for the vast majority of riders.

And the term 'lactate threshold' is bunkum.

I can recommend the polar on line traing diary. It can even create a training plan based on your HRM data. Its also free and givces you an indication of total training load to help you avoid over training. From my experience its a good guide

https://www.polarpersonaltrainer.com/index.ftl

helps to provide structure and motivation 🙂

I think short regualr mix of training is best in different zones. Improve that LT. Gym is also essential to strengthen arms, core, neck, back which you need if your aiming at enduro type distances.

Pawsy_Bear - Member
Gym is also essential to strengthen arms, core, neck, back which you need if your aiming at enduro type distances.

I use Kettlebells for that, a mixture of Swings for Cardio and core strenght plus as weights for everything else.

I hardly ever prescribe what the OP refers to as zone 2. IME it's an utter waste of time for the vast majority of riders.

Do you mean most people don't actually train in zone 2 at all and are actually not taxing the body enough to adapt/get stronger or do you mean most zone 2 training is a waste of time?

most zone 2 training is a waste of time?

this

intriguing!

it's just all you read or hear is 'build the base'.. do some zone 2 rides to build the foundation.. Create a bigger base etc. No need to do loads of intensity in the winter.

iDave is it because of the inherent problems with calculating that level of effort using HR, Ie if you were to move to the equivelent power zone (it would be less of a waste of time) or the concept of Zone 2 for base training being a joke?

I hardly ever prescribe what the OP refers to as zone 2. IME it's an utter waste of time for the vast majority of riders.

I've done Z2 training in the past and although there have been other factors involved it has benefited me.

I'd be interested in hearing why this Zone 2 stuff is a waste of time. I don't really do it myself because I find it too boring and time-consuming.

I'd also like to know why "lactate threshold" is a load of nonsense.

Obviously the ultimate purpose of the training has to be considered but for [i]most[/i] riders there's no need for lots of level 2.

Been [i]thinking[/i] a lot about training recently as currently doing some very unstructured stuff. Went to a Q&A session with some pros last week and they were saying that the idea of slow winter base training is seen as quite out dated these days, which makes me wander if the Joe Friel book is somewhat out of line with modern thinking (I haven't read it yet and have been leant an older copy so maybe I'm being unfair...) - any opinions?

Read this the other day

[url= http://biketechreview.com/performance/supply/47-base-a-new-definition ]Base: A New Definition [/url]

LSD, (Long Slow Distance), training is what Pro's do, as Pro's have the time available for this type of training.

Us lot, who work 40+ hours a week, can not replicate Pro style training, therefore we need to adapt it to fit our 8, 10, 12 hours a week training schedules.

That said I did a lot of technique work in Zone 2 last winter, one leg drils etc, this worked well and killed time whilst it snowed for 3 months.

So what's the current thinking for someone with say, 12 hours a week, to train for a 24 solo or 7 day stage event next summer?

In the past I've followed the base/build/peak cycle, but when time was limited this year I kind of skipped the base part and spent 10 weeks on the Chris Carmichael time-crunched cyclist plan.

I have heard the theories for both approaches so I'm interested in some views.

Obviously the ultimate purpose of the training has to be considered but for most riders there's no need for lots of level 2.

care to elaborate further (or do i have to pay for some expert idave advice/insight 😉

it's so easy to get caught up in all the advice and guidance out there and trying to do the right thing. I know everyone is different and each person responds differently to training.

Agree with the new base approach above and that is my experience to. There is no easy short cut. Physiological adaptation for power and VO2 only happens when the body is stressed above its normal level. There is also more to endurance than training. I should mention good diet and rest are also needed. I hit the trails regularly throughout the winter to keep my skill level but not for training. Better weather sees me doing more on trails and setting some micro goals along the way. Events normally, 12 hour solo, 100km+ CX or enduros. These help to build the psychological strength and knowledge you need to go big. Also allows you to practice eating and drinking. I would also suggest that you train in your event clothes and boots. All this together can have a tremendous boost to your ability level.

Hours at zone 2 give very few exclusive fitness gains - you can get fitter/faster, in less time with a different approach. Even training to be efficient at fat burning can be achieved by certain interval sessions at certain times.

IMO many coaches prescribe zone 2 as it fills time in a schedule and makes it look like they're earning their fee's. I'd rather make efficient use of a clients time, but of course some can't see that I've saved them x hours per week. They think that paying for training means there should be lots of training rather than the minimum effective amount which is closer to my approach.

Correct me if I'm wrong, but isn't the idea of Z2 training to ride in you fat burning zone and over time you will naturally get faster/ stronger within this zone therefore being able to ride faster for longer and eliminating the chance of going into you sugar burning zones too early as tempo increases? Also doesn't this reduce the gap between Z2 and you LT zone?

I may have missed the point and be talking complete horlicks!

therefore being able to ride faster for longer and eliminating the chance of going into you sugar burning zones too early as tempo increases?

What if tempo is high at the start of whatever event it is you're describing?

As for a 'lactate threshold', it was discredited in the 80's when I was a mere student. Can't believe it's still being thrown around.

There is a threshold and it's 'causes' are numerous - including psychological factors.

Interesting read - started thinking about HR zone training as I've just returned to racing after a year off with a busted collar bone. Never really thought about training certain zones, just went for a ride - but would really like to improve for next season.

I don't think I would find it physically possible to ride at zone 2.... I did the 4hr rd1 BM on sunday - I went out far to fast (for me), ended up with severe cramps after about 2.5hrs of averaging zone 4.5 and spent the next 2hrs in lots of pain - is this my lactic threashold then?

Does anyone fancy spending 5 mins looking at my garmin trace and recommending me what I need to work on?
http://connect.garmin.com/activity/131322194

I've just ordered the Joe Friel book to get a better understanding

beej your plan is correct. But why compress it? Start your base now. You can then enter the build phase at a much higher level and so step up to peak at a higher level that way you will achieve a higher level fitness. I try to maintain a good base all year. In all stages your always trying to build, rest build. But see my comments about a holistic approach.

DT From post its your LT. Essential you were working at or over your LT. Once in the sugar burn zone you consume water and energy faster than your body can usefully replace it and lactic acid builds up leading to your cramps. Slowing slightly and raising your LT will combat this problem. Your LT, depending on how you measure will be a % or bpm of your MHR. I use % as its easier to remember. 70% - 80% Zone 3 80% - 90% Zone 4. My LTs about 80 - 85% depending on tiredness. On long enduros I use electrolyte drinks, carbo food and salt sandwiches to combat cramps - works for me and its a favourite 🙂 Also steady warm up and down helps. You started out way too fast for your fitness level and hit near your maximum HR is first 10 mins then went down hill. P.S I know that area well 🙂

As for a 'lactate threshold', it was discredited in the 80's when I was a mere student. Can't believe it's still being thrown around.

It's more than thrown around.

In what way has it been discredited?

There are many theories. I started out on the LSD plan but I have turned to the dark side as I see more benefit for shorter time spent training.

I think training should be driven by goals or your plans will just not make sense. For most effect you need to measure and monitor and adapt plans based on performance results. That to me seems obvious? There are many factors that go in to gaining superior performance as I mentioned. Not just the adoption of a single theory of everything for that refer to Steven Hawking 😉

i've found a really effective way to get into the fat burning zone (or rather train your body to burn fuel more effectivley) is to train on an empty stomach - first thing in the morning for a couple of hours is idea

i tried this on gut instinct (pun intended) many years ago when i used to race xc, i was forever getting the bonk - and this approach really worked well

as an aside, i read that Pro roadies are increasingly doing these sessions*

* but as a disclaimer - what works for me, may not work for you

Winter base miles? It's only when you have bonked so hard you forget the way home that you know you've had a good session

[url= http://twitter.com/MTFU_Training ]http://twitter.com/MTFU_Training[/url]

Thanks for the feedback PB - yep knew I went out too fast, got carried away at the start - only my second race in as many years so I haven't got the right race thinking yet - I just hate letting people past when I know I can go faster even if going faster means I suffer badly later on.

Takes real willpower to pace yourself properly. I have the garmin beep at me angrily when the HR goes over 180 - still haven't learnt!

P_B - I started my first base period this week, things are slightly complicated by my main goal being mid August - previously I've done 3 months base/ 2 months build then a 2 week peak. I've put an "A" race in for the start of April as well so that I don't spend then next 5 months just doing base work.

Current weekly plan is 2 weights sessions (strength), some low power sprints for leg speed, single/dominant leg work for technique and a couple of zone 2-3 rides of 2-3 hours each.

DT78 - This/last year (2011) for Training I basically rode/re rode the distances on MTB that I was racing ie 50k etc using Endomondo to record / improve my times.

Doing that repetitively I established my own average KPH for the ride, lopped off 1kmh for the race and rode at that pace (about 16kph this year) for the first half of the race.

I then upped the average 1kph for the third 25%, then went as fast as I could finish for the last 25k.

I picked up loads of places at the end. I was given this advice and it worked for me, my highest result was a 2.25 50k and 4th place.

It depends whose riding of course - same strategy at the Gorrick 50 left me in 33rd - although in thats case I like to think places 1-32 were Team Torq riders.... 🙂

TBH though there are other factors - at the Gorrick which was very dry, I got beaten up by the trail and felt very uncomfortable on my HT and should have taken a FS, my third lap was aweful, based on the fact I was beaten to death, rather than aerobically exhausted.

Note, I didnt use a Road bike this year, or start training for events until about 27 December last year so I consider my performance to be "not bad" considering. Road bikes to me are a new concept only 3 months or so old....

Received my Joe Friel book at lunch time. Is it a training book that need to be rear all the way through to gain an understanding or one that you pick parts of to suit your needs?

The threshold is not a lactate threshold, nor an 'anaerobic' threshold. It's simply an intensity threshold the level of which and causes of which vary daily. And the actual definition in terms of trying to establish 'where' it is isn't clear. If you base it on a 30 minute test, what's the relevance to a sportive? If you base it on a one hour value, what's the relevance to a 24?

Is it a training book that need to be rear all the way through to gain an understanding or one that you pick parts of to suit your needs?

I read mine cover to cover, (its an easy and quick read if you've got prior knowledge of training principles), then when back and re-read the more interesting bits and started to piece together a plan.

The threshold is not a lactate threshold

By this do you mean you don't use lactate threshold or don't believe there is one?

(i am a little confused by your statement)

The threshold is not a lactate threshold, nor an 'anaerobic' threshold. It's simply an intensity threshold the level of which and causes of which vary daily

So would training for threshold be more suited to the type of racing you'll be doing and the hardest possible scenario? i.e. if its for hour long closed circuit road racing then that would be your training goal?

What I mean is that levels of lactate in the blood are not a good indicator that you're at an intensity (threshold) that you can sustain when you ride. Exercising muscle doesn't just switch from one fuel to another or from oxygen dependent metabolism to non-oxygen dependent. It's a big messy flow and flux with many contributing factors. The most important role of lactate during exercise is fuel. It's not the bogeyman.

Any coach who dresses up their service in psuedo-science is misleading themselves about how the complexity of how the body operates under physical stress. We know much less about it than we don't know.

Hours at zone 2 give very few exclusive fitness gains - you can get fitter/faster, in less time with a different approach. Even training to be efficient at fat burning can be achieved by certain interval sessions at certain times.

IMO many coaches prescribe zone 2 as it fills time in a schedule and makes it look like they're earning their fee's. I'd rather make efficient use of a clients time, but of course some can't see that I've saved them x hours per week. They think that paying for training means there should be lots of training rather than the minimum effective amount which is closer to my approach.

I agree with this (I am a distance runner and only cycle a bit) but from a running point of view IMO there are only trivial benefits to be had by running "easy" (probably in the Z2 range although similar effort when running often translates into a slightly higher HR) these benefits may be weight loss and small benefits to cardiovascular fitness. However they are outweighed by the greater risk of injury/illness and the additional tireness detracting from performance enhancing sessions.

beej - we have the same plan! 🙂 Just keep stepping up in each phase, rest move up.

DT78 in trans alps this year we went out slow and was well down the field on day one. But each day we moved up the field. We werent getting better - they were getting worse and expending energy faster than than they could afford. Allowed us to put in some attacks later on in the week gaining quite a few places.

Agree with you idave. Whats its use? Well for me I look at it as a measure of potential performance. For example two riders are going up the same hill at the same intensity level realtive to their own fitness the one with the higher intensity or threshold level will get to the top first ie he puts down more power for the same physical effort or intensity. So to go further faster I need a higher threshold. Works the same on 12 - 24 hour solo or multi day events when its extremly important. Knowing where the threshold is also allows to manage your enegry levels and stay below that threshold on attacks or steep ups etc. On big multi day or solo I manage the race based on my HRM zones.

Training empty? Well weight is ok so no need to fat burn in my case. I find I snack 24/7. Whilst mainataining a low overal weight is helpful to go really hard I must fuel and without it your risk lowering your immune system. I rate fuel, sleep and rcovery as important as time in the saddle. It all has to be managed within the time available.

Training to be efficient at fat burning and losing fat are two different things PB.

What I mean is that levels of lactate in the blood are not a good indicator that you're at an intensity (threshold) that you can sustain when you ride

Turning it around though, would you agree they are a good indicator of a level that is [u]not[/u] sustainable?

I'm not sure that running training can be applied to cycling though.

Running is much harder on the body than cycling so increased volume carries a far greater risk of injury in running than cycling. I doubt even full time runners won't be putting in the same hours as full time riders.

No because our individual threshold is variable and complex and just having a certain lactate level in the blood doesn't mean you're going to grind to a halt on a certain day with a certain diet and mindset. For example, I sustained 185 hr for 2 hours when my laboratory set 'lactate' threshold was supposed to be 172.

to go back to OP i don't think anyone answered

Now, either theres something wrong with me, or Zone 2 is really, really slow

think irrespective of how you calculate max HR or use lactate threshold one good thing about using a HRM will do is tell you that often or not you are working too hard when in recovery or fatburning - doesn't feel like exercise or training but is doing what it is supposed to do - that is irrespective of whether or not it is the most effective training program - that has sort of got covered

but in theory if your lab lactate threshold was 180 (no other differences) then on that day you would have been able to sustain 185 hr for longer than the 2 hours?

I think people will use whatever programme/method/latest thing they feel most comfortable with or easiest to live with.

FWIW, I "feel" like I've had some good progress using the Friel approach & I like riding my bike, so if I didn't ride at "Zone 2" a lot of the time I'd be pretty burnt out. I also enjoy a lot of road riding & there's no way I could sustain a Zone 4/5 effort for 4 hrs on the road. Can hold that effort for that long in an mtb race though, because of the amount of time you have to recover on decsents & when you're stuck behind slower riders.