LT & HR zones

[EdinburghFixed]

I've got myself a turbo so that I can get some quality time staring at a wall this winter!

In an attempt to have just a little structure, I decided to test for approximate lactate threshold so I can train based on zones. As I'm quite new to this whole idea I just thought I'd run it past anybody here who has a bit more experience....

This morning I rode a 30 minute "time trial" and took the average HR of the last 20 minutes, which is supposed to roughly approximate LT if I understand all this stuff correctly.

For me, this figure was 176bpm. (Actually if anyone can really be bothered, you can see the whole "time trial" trace).

Based on this, I've calculated the following zones:

< 141	Recovery
141 - 155	Aerobic
155 - 165	Threshold
165 - 176	Lactate
176 >	VO2 max

Does this look right?

The main thing that makes me cautious about it is that it's quite high.

I worked out my maximum HR to be about 194 (but only by using the 220 - half age - 5% of weight + 4 formula) - the highest I've seen on a GPS trace is 190. But it means my LT is 90% of MHR, which is surely wrong.

I guess the simple explanation is that my max HR might actually be quite a lot higher than I ever see on the bike, strange as that would seem.

[LittleWheelsandBig]

Back when I raced, my max HR was 200 bpm and my TT HR (for 40km) was around 181 bpm. YMMV

[border-rider]

Everyone's different. Even when I was in my 30s I'd struggle to get my HR above 185, and 190 was about max.  Knock 10 off that these days. My aerobic threshold is about 140.

[simonp]

For me:

HRmax (measured) 192bpm
LT 155bpm

I can maintain a much higher HR than 155 for 20 minutes.

[EdinburghFixed]

Simon,

Sounds more reasonable to me. I think I must be getting confused over what I actually want to estimate.

I have the training bible by Friel. He says: "Merely complete a thirty-minute time trial... click the lap button on your heart rate monitor ten minutes into the time trial. Your average heart rate for the last twenty minutes is a good estimation of LTHR (lactate threshold heart rate)". And then goes on to determine zones according to percentages.

According to these results, cherry picking from his workout "menu" I'd be looking at having a 3h long ride at HR under 155, things like tempo rides at 155-165, threshold rides from 165 - 180. I know you train with power, so at the risk of comparing apples to oranges - does that sound plausible to you?

I'm not too worried if it's slightly adrift because I only got the turbo as an alternative to not riding at all. I just feel like if I'm going to invest time riding it, I should try to do so with some idea of "right" and "wrong".

[simonp]

I don't know, tbh. My LT at 80% MHR is fairly normal. But it's possible you're different or your MHR is higher.

[EdinburghFixed]

OK. Well, I guess it might be obvious if I find it impossible to complete the suggested workouts, or have a heart attack ;-)

Incidentally, the cold weather has finally come in handy for something. I have the turbo set up in an unheated room (converted balcony) off the end of the flat and it's so frigid that I had barely started cooking even at 180bpm. 

[hugo15]

It sounds about right. I did the same test a few months ago and my LT was 170. I was working off a MHR of 185, but I suspect that it is a few beats high than this.

I've been reading the Freil book too.

I also found the Pete Reed Black book, which works off similar principles of building an aerobic base, quite useful. It is more a riding plan and is aimed at using the turbo.

[simonp]

Watts, RPM, Lactate, HR data from my test last year:

100 85 2.8 120
125 85 1.8 125
150 85 1.3 131
175 85 1.8 134
200 85 1.8 145
225 85 2.6 155
250 85 5.0 160
275 85 5.8 167

LT is at 225W/155bpm.

It would be interesting to do a time-trial test to see if it produces a similar result.  Unfortunately, it's a year later now and I expect that my LT is now higher than it was.

[simonp]

(From this data, I do LT intervals at around 225W, and shorter (5 min) intervals at 250+).

[mattc]

According to these results, cherry picking from his workout "menu" I'd be looking at having a 3h long ride at HR under 155, things like tempo rides at 155-165, threshold rides from 165 - 180.

If I scale my zones up (because your HRmax is higher than mine), these look spot-on. Your long ride and "threshold rides" look fine. (I'm not convinced about doing tempo rides at all, but that's a whole nother story ... !)

I couldn't see your heart-rate graph (my screen is too narrow for that page  ). You may find that with practice riding at/above threshold, your 20-30minute max creeps up a bit. Or you may not. A few months training at zones that are a smidge low will do no harm, so go with what you've got for now. You can always retest in 3-6 months.

People get very worked up about "errors" in HRmax and LT of just 3-5 beats. These make no appreciable differences to the lower zones, and not very much to LT sessions, so don't fret.

[EdinburghFixed]

Awesome, thanks Matt.

To be honest I'm going to mostly be focusing on the aerobic stuff anyway - I'm not going to get far at PBP riding any other way.

There are two things I haven't quite figured out yet:

- If I choose to split my workouts so that I do, say, 30-60 minutes twice in a day (i.e. getting up and after dinner) rather than riding steadily for one whole block, do I get an equivalent benefit or is it not as effective? I can fit in one long ride a week but the rest need to slot in around "real life".

- Second, without power I'm going to be following a program that just specifies intensity as "zone 2" or "zone 4" etc. Does it matter at which end of the zone I am? i.e. do you get a better aerobic training effect just under the transition to zone 3, or should I conserve energy on the bike by riding just above zone 1? (I suppose the safe answer is, to be sure that it's the right zone, ride in the middle!)

[mattc]

- If I choose to split my workouts so that I do, say, 30-60 minutes twice in a day (i.e. getting up and after dinner) rather than riding steadily for one whole block, do I get an equivalent benefit or is it not as effective? I can fit in one long ride a week but the rest need to slot in around "real life".

I think there are too many variables here! I would say that 2x30mins at low intensity is just as valuable as 60mins. But if, say, doing 20min intervals, 30mins is probably too short to warm up enough (and cool down). There are doubtless many other special cases that we could concoct ...

- Second, without power I'm going to be following a program that just specifies intensity as "zone 2" or "zone 4" etc. Does it matter at which end of the zone I am? i.e. do you get a better aerobic training effect just under the transition to zone 3, or should I conserve energy on the bike by riding just above zone 1? (I suppose the safe answer is, to be sure that it's the right zone, ride in the middle!)

The way I use this stuff is to aim for the middle, but not fret too much as I drift up and down a bit. this seems to fit the "ethos" of what zones actually are, IYSWIM!

[amaferanga]

30 mins isn't enough time to get much if anything out of a session IMO.  That'd be 10 minute warm-up, 10 minutes proper riding, 10 minute cool-down.  Better than nothing though obviously. 

Just my opinion, but unless you're doing high intensity stuff (say 5 minute VO2max intervals or 2 minute anaerobic intervals) then the minimum you'll need for a proper session is an hour.  So if you've got 1-2 hours a day then try to set aside a single block for your training.  At the moment I'm doing FTP build sessions and L3 sessions and these vary from 70 minutes (2x20 L4 with 10min warm-up/10min rest/10min cool down) to 95 minutes (75 mins L3 with 10min warm-up/10min cool down).  I think you'll find that 30 minutes at L3 is ridiculously easy (and 10 minutes at L4 should also be fairly painless).

If you are using HR to pace them then you might want to work out a strategy for actually determining what HR a given interval is done at that takes cardiac drift into account.  If done at a fixed intensity (only really measurable with a power meter or if you have a very stable turbo trainer - not a fluid one) then your HR at the end of the interval should be quite a bit higher than near the start (e.g. this - constant power through the intervals apart from the last few minutes of the final one, but HR is rising throughout).  Also, don't go out too hard at the start just to get your HR up to the zone straight away.  I'd say that for a 20 minute L4 interval you should be hitting the zone after a few minutes.

[EdinburghFixed]

Thanks guys.

It's interesting trying these things out. Unless my LTHR calculation was way off, even L2 is harder than I thought a "long slow ride" would be.

Bringing my HR up slowly, I notice a shift in breathing at about 130bpm but L2 doesn't start until 141 - by which time it definitely feels like I'm working (although yes, I could obviously keep it up for a while!)

Previously I've always either been riding to work (more like intervals and working the traffic keeps me pushing hard) or I've been riding brevets (slowly, without much in the way of metrics).

Looking at those brevets where I've used the HR belt, my average HR is in the low to mid 130's. That generally includes the control for the given leg, so perhaps 135 is a fairer number.

Hrmm. I'd love a powertap but it's not really practical (20" drive wheel with disc brake, before we even get on to the cost).

[mattc]

If done at a fixed intensity (only really measurable with a power meter or if you have a very stable turbo trainer - not a fluid one) then your HR at the end of the interval should be quite a bit higher than near the start (e.g. this - constant power through the intervals apart from the last few minutes of the final one, but HR is rising throughout).  Also, don't go out too hard at the start just to get your HR up to the zone straight away.  I'd say that for a 20 minute L4 interval you should be hitting the zone after a few minutes.

Good tip. I suspect this is where many HRM users go wrong (and why some peeps think you NEED a power-meter )

Something interesting about that session, amaf; in the first 20min interval, you seem to get steadily faster at a constant power output. But the 2nd and 3rd intervals are more stable. I think this shows how lots of things change while we warmup, and you have to take figures with a pinch of salt early in a ride.

[If I ride intervals like that, I keep the first one quite short and just regard is as part of the warm-up.]

[simonp]

If done at a fixed intensity (only really measurable with a power meter or if you have a very stable turbo trainer - not a fluid one) then your HR at the end of the interval should be quite a bit higher than near the start (e.g. this - constant power through the intervals apart from the last few minutes of the final one, but HR is rising throughout).  Also, don't go out too hard at the start just to get your HR up to the zone straight away.  I'd say that for a 20 minute L4 interval you should be hitting the zone after a few minutes.

Good tip. I suspect this is where many HRM users go wrong (and why some peeps think you NEED a power-meter )

Something interesting about that session, amaf; in the first 20min interval, you seem to get steadily faster at a constant power output. But the 2nd and 3rd intervals are more stable. I think this shows how lots of things change while we warmup, and you have to take figures with a pinch of salt early in a ride.

[If I ride intervals like that, I keep the first one quite short and just regard is as part of the warm-up.]

What it shows is that the resistance from the turbo changes as it warms up, which is why you can't pace yourself correctly on a turbo without a power meter.

[LittleWheelsandBig]

If you are using a fluid resistance trainer. When I raced, we used windtrainers as the resistance was much more constant.

[EdinburghFixed]

Surely the resistance changes in a predictable way wrt heat, though? i.e. the viscosity of the fluid (or whatever the limiting mechanism is) is constant at a given temperature.

[mattc]

Surely the resistance changes in a predictable way wrt heat, though? i.e. the viscosity of the fluid (or whatever the limiting mechanism is) is constant at a given temperature.

Probably; but only once you've warmed it up!

[amaferanga]

Surely the resistance changes in a predictable way wrt heat, though? i.e. the viscosity of the fluid (or whatever the limiting mechanism is) is constant at a given temperature.

If the unit is at the same temperature and you do you exact same workout then I guess its repeatable.  Mine is in the garage and I do different workouts so its next to useless for gauging intensity.  Its an Elite Supercrono elastogel fluid trainer btw.  Before I got the PM I used to play the game of guessing how much my HR should be drifting during an interval and slowly upped the speed.  As you can see from the GC link it takes about an hour to even get close to stabilising by which time most folk are finishing their workout!

A powermeter is probably the only way to remove the uncertainty. 

Also, you mentioned your workouts for a given HR felt harder on the turbo - I find the same.  In fact I struggle to get my HR up on the turbo.  I can probably average 10-15 bpm higher on the road for an hour all out and can't get close to my HRmax on the turbo (not that I've tried that often). 

[simonp]

Surely the resistance changes in a predictable way wrt heat, though? i.e. the viscosity of the fluid (or whatever the limiting mechanism is) is constant at a given temperature.

Probably; but only once you've warmed it up!

Just looked at a graph of one of my interval sessions:

http://homepage.ntlworld.com/simon.proven/3x15-feb.png

You can see the same temperature drift there.  I've never really noticed it before as I ignore the speed when doing intervals.  It takes about 25-30 minutes before the turbo is fully warmed up.  No way do I want to spend that much time warming up.

[inc]

Your original time trial looked like it was done at 32kph I don't think this is hard enough to get representative working HR from. If you intend to use HR as the main factor for determining your training zones you need an accurate max HR to work back from otherwise your zones are being based on a submaximal effort. There are hundreds of "Training" books but they are nearly all based on the work by British physiologist Peter Keen. Here is a link to the original article by him in Cycling from the early 90's and well worth a read.  Peter Keen - everything you need to know about training! - Timetrialling Forum

[EdinburghFixed]

I'm not sure I understand - surely the speed (and gearing) is just an artifact of the trainer resistance? I mean, I could reduce trainer resistance and go at 50kph but it would be the same workout, right?

No doubt I could have gone harder if someone was holding a gun to my head, but probably not that much - 190bpm is the highest heart rate I have recorded on any bike session over the last 18 months (of the ones that are on Garmin Connect, anyway). By the end of the 30 minute TT I was steady at 180bpm - that's 95%.

Even if my true max HR is 10 beats higher, it would still be steady at 90%. Isn't this broadly right?

[mattc]

I'm not sure I understand - surely the speed (and gearing) is just an artifact of the trainer resistance? I mean, I could reduce trainer resistance and go at 50kph but it would be the same workout, right?

Yup.