UKC

This is one of those things I’ve wondered about for decades and only just decided to ask...

Using a heart rate monitor (Polar, chest strap) I’ve seen tables of HR for training zones but when I’m out on the bike I find I’m in zone 5 (of 5) or upper zone 4 practically all the time, regardless of the length of the run:

• Zone 1: 50 percent to 60 percent of MHR
• Zone 2: 60 percent to 70 percent of MHR
• Zone 3:70 percent to 80 percent of MHR
• Zone 4: 80 percent to 90 percent of MHR
• Zone 5: 90 percent to 100 percent of MHR

I’m reasonably fit, hill-fit even (since this is UKC), but as soon as I begin to exercise my heart rate goes right to the upper end of the range and stays there quite happily for the duration. It’s practically impossible for me to get down to level 2 on the bike and I only see upper level 3 when coasting if the downhill is long enough! 

For example, on a 60 mile run yesterday, rolling hilly 3000ft, 3:50, my average heart rate was 154 and the highest I saw was 170 ( I count my ‘maximum’ as 175, I’m 61). When I was younger, in my 20s and 30s my HR would routinely sit at 180 when walking uphill, even when I was at my very fittest. My resting HR is 48 as I write.

I’ve no pains or problems or ill effects, just curious as to whether folk find heartrate tables useful or like me, find they bear little relation to perceived effort and heart response? Am I less fit than I think or is my experience common?

In reply to Basemetal:

Same - my heart rate tracks the zones when I’m indoors on the turbo, but always stays high when I’m doing real cycling.

People have suggested that it’s because I’m using more muscles on the bike, or I’m not relaxing as much, but in my mind that doesn’t explain the disparity - I just don’t pay attention to heart rate when outdoors.

In reply to Basemetal:

I had this, turned out I hadn't actually buried myself enough to establish what my max heartrate is. Even on tough short climbs I don't always push above 95% unless I go hard enough to need a rest at the top. I've also since sacked off the max heartrate zone model and gone for zones based around threshold heartrate as established using Intervals.icu.

In reply to Basemetal:

Maybe a period of doing long, low intensity rides will “reset” it. That’s what happens with me and I’ve read about the phenomenon in sports science textbooks. Another thing to consider is warming up. I find if I go too deep for too long early in a ride it elevates my heart rate thereafter. The response above about the turbo is odd; my experience and I though received wisdom is that HR is higher indoors, probably owing to heat. 

In reply to BenedictIEP:

I find to get to my max heart rate it needs a sustained hard effort for about 20 mins followed by emptying the tank, like in races. Even on a hill climb lasting 8 mins I’d be a little way off max even though I’d be massively in the red. 

In reply to Basemetal:

Haven’t watched this but might help  youtube.com/watch?v=JJRN8ZxIUgM&

In reply to Basemetal:

I think that your maximum heart rate should be 159 (220 - 61). That said, the fitter you are the less that should matter. 

Insofar as zones are concerned, these tell you what sort of exercise that your doing (endurance, aerobic, etc) so they can be useful if you're aiming for a specific goal.

I'm 58: climbing recently I had a bit of a wobble and my heart rate spiked at 197. I'm almost certainly dead. 😁

In reply to Basemetal:

Is your maximum HR of 175 a guess? I’m the same age and resting HR as you and regularly reach more than that, and it sounds like you are fitter than me. As Benedict says, it might be worth beasting yourself briefly to establish your true maximum.

In reply to VSisjustascramble:

I find my heart  rate responds the same indoors or out, to any exercise basically.

In reply to BendictIEP

Uh-oh, that's scary! I might have to look at this. Once (40 y ago) after a series of tetanus shots I was asked if a "double volume donation" of blood could be taken to use for human serum (as opposed to the usual horse) for allergic patient use.  A few days later I was walking up Bidean nam Bian and kept hearing a helicopter very close, but my friend couldn't. Being a medic he checked my pulse and counted 70 beats in 15 seconds. Twice. I'd interpreted "don't do anything strenuous at the weekend" as go hillwalking rather than climbing.

So maybe I should plug 280 in as MHR rather than 175? (or more logically, extrapolate an MHR figure from taking my long run average as Moderate?)

Seriously though, If I do hammer myself I think I max out at 175 but I'll give it a shot...

In reply to Yanis Nayu

I've noticed this lifelong, even over periods of relatively little activity, injury, illness etc. so suspect there isn't a reset option.

Like BenedictIEP's point, this one is a possible. I can do an impression of a beetroot breathing razor blades in a 10 minute effort and just see 175, but I may need to experiment a bit a more.

Thanks for the comments guys

In reply to Basemetal:

But this is UKC, surely your blood is boiling, you are foaming at the mouth whilst screaming at the screen ...  HR>>170

In reply to rsc:

Not a guess,  but the highest I've seen when wearing the monitor over most of a year on the bike (3k miles) and occasionally long days in the hills. Apart from the low blood volume episode I described above (when I was 21) I don't think I've ever seen 190, but maxed out somewhere in the 180s until the last few years.

In reply to Basemetal:

Do a proper heart rate test otherwise everything will be way off if you are estimating/guessing.

After establishing your MHR you should be on the verge of being sick with no desire to repeat the test for a good while.

In reply to JohnDexter

My reason for renewed interest in this was looking to maximise my endurance by cycling in Level 3 (on the flat at least).  But my heart throttle seems to be more like a Hi-Lo  on-off switch than a gently tapered needle valve, if you get my drift.

In reply to PaulW:

I'll bite the bullet and report back if I get above 175...

In reply to Basemetal:

Then it's not your max.  Its probably just below your threshold else you'd be blowing  up here, there and everywhere.

The other possibility is that your threshold is really close to your max due to all the miles with no 'quality' (bad phrase), so you don't blow up, but can't ever go much faster. This actually might be your most likely situation.

If you warm up, then try a couple of 2,3 minute hill climbs to the point you are ready to puke, then you're getting close to max

In reply to wbo2:

Thanks! This sounds quite probable. Most of my riding has been solo local circuits of 90-120 minutes with some quite painful 2-10 minute hills at 4-8%  and a few trips out to longer steeper ones (like the Suie and Cairn o'Mount). A year ago some of the hills had me all but throwing up (HR 175) and now I can get up with my eyes uncrossed and breathing properly (HR170). 

I wasn't pursuing quality training so much as just "riding my bike", but I've got sucked into enjoying the speed. So I should revisit the max effort approach .

In reply to JohnDexter:

As no-else has called it out, I'd like to point out that the idea that the calculation for max HR  being 220-age has been proven completely wrong.

In reply to Basemetal:

If you are training that close to your max you should be barely able to get a word out, is the that the case? Although if you are able to sustain the effort for 10 minutes or so then it’s almost certainly not your max. 

Another thing to consider are protocols for estimating your lactate threshold heart rate (point where you are producing lactate faster than you can clear it, or the max effort you can sustain for ~1 hour). This gives a different benchmark to estimate zones from, without having to put yourself through a max heart rate test.

I prefer this method as it means you know the point where you tip into the red zone, rather than just estimating it from the max. Knowing your max value itself isn’t all that useful since you’ll never really be training at that intensity. It’s only useful as a value from which to estimate other values, so to my mind you might as well skip the middle man and just measure lactate threshold which has much more direct relevance to training. 

In reply to Stuart Williams:

Yep, that's pretty much the case. I'm not able to hold 175 for ten minutes, that's just the highest number I see during my hardest climb efforts. I'll have my pain face on and may be involuntarily whimpering in a manly,  gaspy way... .  What I haven't done is hill repeats to see what the max does.

In reply to Basemetal:

Yes, HR zone tables are useful but for me are more accurate when calculated off my lactate threshold heart rate (LTHR),  this being something that can actually be tested whereas testing for max HR is either extremely painful or subjective depending on how far I am willing to push myself, or both. 

A good clue that zones defined by MHR are wrong for me is that I can ride for a few hours at 80% MHR without eating and not bonk. 

Z2 based on MHR would be 111-130

Z2 based on 70-87% of LTHR is 120-150

The zone based on MHR is way to low for me.

Doing the Sufferfest 4DP fitness test totally changed my perception of RPE, turned out that I was riding the easy stuff way to hard and the hard stuff way too easy.

RPE for zones

Z1 ( recovery) a gear so easy that it feels like there is almost no resistance, can spin out to 120rpm with ease.

Z2 (Endurance)slightly harder than Z1 but spinning above a comfortable cadence starts to feel like work

Z3 (Tempo) starting to put some force on the pedals

Z4 (threshold) I have to concentrate to keep the effort on

Z5 ( VO2 max) My goodness make it stop

Z6 (Sprinting) Stomping as hard as possible 

In reply to Jon Greengrass:

Completely wrong? Haskell's formula does have the benefit of being derived from meta data rather than smaller studies, but choose your poison 😁

As George Box once said, "All models are wrong, some are useful"

I acknowledge that there are a number of ways to calculate maximum heart rate (Hunt, Miller, Winfried Spanaus, et al), but, in my view, for a Q&D estimate, it's easier to take one's age from 220 than to multiply age and weight by different factors and then subtract them from arbitrary numbers. Moreover, fitness, weight, lifestyle, and any number of underlying health conditions might render any result moot.

All that said Jon, I agree with you, it's probably inaccurate and the only sure way to get the correct reading is to calculate your own but that doesn't mean that it's not a reasonable guide.

In reply to Basemetal:

Ah I see, that’s my fault for not reading more carefully. I’d still expect your max to be a bit higher than that due to heart rate lag - it needs the maximal repeats to get a reasonable measure. For me, pain face and gasping definitely starts a good way below my max!

In reply to Basemetal:

I'm 70, saw a HR of 163 today finishing a 20 minute effort with a near-max sprint (on a Wattbike, indoors) and I get to see the same figure after a 5k parkun with a sprint. Maybe saw 170 a couple of brief times over the last couple of years. For me, HR is very dependent upon how hard I have been training and if I have eaten - normally I would run or bike on an empty stomach and usually HR stays lower by at least 10 beats as a result. Current resting is 48, like you.

Phil Maffetone is a running coach with a formula for aerobic training - simply 180 minus age - which for me is currently 110. The theory is that if you run/bike and your rate goes higher you slow or pause until it drops again. You are supposed to train like this for several months with no racing etc until you build up a decent aerobic base, and you can manage with nose breathing at your aerobic pace. I was sceptical as I walk at that sort of HR (when I can walk, got sciatica currently) but during recovery from hip replacement and also the 'beast from the east' winter I spent hours indoors trying to maximise power within average HR of 115 (yes, I cheated a bit) and eventually got to 150 watts over 30km equivalent. For running, I used 'under 130' because I felt there was no improvement at 115 - which was walk/jog intervals - and I certainly got fitter over the last year..

Sometimes I have had inexplicable heartrates at the start of long runs - over 150 warming up, downhill jogging, which resets to 140 or less when the pace picked up for the main event - why would that happen?

In reply to petemeads:

I'll typically do one fasted circuit of about 30 miles each week, but  I hadn't been watching for an effect on HR. There's a good 7 minute hill on my route to check with though...

I'm not sure I'd be able to ride anywhere and keep my pulse below 120 (180-60 for me). I don't have an indoor trainer and the village I live in is in a dip with every road out being a climb for a mile or so. Apart from the geography, even on the flat my HR will go higher while I'm very much aerobic and not perceiving much effort at all. I can breath through my nose happily at 150, tho physiologically I guess that doesn't mean anything (other than a big nose?). 

Your tachycardias remind me of the thing that affects fit young men with too much iron.... but I'm no medic...

In reply to Basemetal:

As someone else said, I suspect lactate threshold heart rate is more useful for setting training zones. My max is 197 (I’m 50) and my LTHR is 172. LTHR minus 30 is supposed to roughly represent your aerobic threshold and is a good place to aim for long efforts (say 90 mins) to train your endurance. 

In reply to Yanis Nayu:

Do you find you can stay at 142 for a long effort? I've been trying to get down to 140 which would be my as yet unreconstructed (as in OP case) Zone 3/4 boundary and find I'm practically always over it.

In reply to Basemetal:

I’m 64 and my MHr is 189, on a 30min tt I’ll probably average 92% and reach 96% on a final sprint. My mhr is very similar for both running and cycling although it used to be 10bpm lower for cycling

In reply to Basemetal:

Yes I can. It will drift upwards though as fatigue sets in, especially when it’s hot. As an example I did a steady 50 miler the other day with 2300 ft of climbing at 17.5mph and my average HR was 120, max 160. I used to be like you when I only trained 5 or 6 hours per week. I do 10-15 now and have done consistently for 5 years. 

In reply to Yanis Nayu:

Ah, so the fitter I am the more I can usefully do in a lower zone? Makes sense.

In reply to Basemetal:

Maybe you’re just a fast beater, my max hr is 205 (I’m now late 40s) and like you my resting heart rate drops to ~50.  I can hold close to my max for near ten minutes😮.  We’re just outliers but it is handy when racing up hills😀

Cheers

Toby

In reply to Basemetal:

That seems a bit weird but in the past so....

As others have covered tables tend not to be much use unless you can get properly assessed to get a proper max. Maybe see if a local uni is running any studies (I was really irritated when I saw a note about a study too late to participate a while back).

Cycling I find easier to stay in the lower zones but then again mostly do mtb where getting it up higher with the gearing on the bike is a)hard and b)boring on the road and impossible offroad unless I want to be wearing a tree.

Running I ramp up fast but I tend to find the legs give up before I can really feel I am maxing out heart rate wise.

Well… armed with the received wisdom of this thread (Thanks everybody ) I had a go at practically measuring my MHR and LTR.

I used a 90 minute (24mile 500m ascent) circuit I know well to measure LTR as my average HR over the middle 60 minutes staying on the gas like a Time Trial. Straight after that (to mimic “end of race” efforts and properly “burying “myself) I tried hill repeats up a 5 minute (5-8%) hill to see how high I could get my HR, regardless of whether I’d be able to keep going.

Started with extra jam on toast and lots of coffee for breakfast. Then about two hours later, after a glass of juice and a banana, I headed out. So no fasted reductions in HR expected.

It was cool today, 13C, overcast with an 8 mph wind, but I’m only interested in effort and HR, not speed or time.

Over my "Hour", perceived effort was between Jon’s Z4 ‘I have to concentrate to keep the pressure on’ and Z5 ‘Make it Stop’ on the hills. Average HR was 160, Highest I saw was 171.

On the Hill repeats I tried to go all in but could only face two. On the first my HR got to 177 and held there till I ran out of legs and lungs (a very long minute and a bit) and the number started dropping as I slowed. On the second (no recovery gap beyond the freewheel back down, say 6 minutes) I got my HR to 173 but I had to stop before the top for a mild case of imminent death. I vetoed a third run for today at least.

I’m aware different days and different methods can give different results, but I think I’m seeing confirmation my MHR is in the region of the 175 I suspected. I wouldn’t expect, for example,  to see even 10 beats more anyhow. Applying this to the HR tables, plugging in 177 rather than 175 makes no practical difference to the 10 percentile training zones I've been looking at. My intuition is that the linear progression of the zones is just not how I’m wired.

As Toby_W put it, I may just be a “fast beater” - wired so I don’t ‘use’ intermediate heart rates much. A question is whether that’s a fitness or training deficit or just a physiological idiosyncracy. When I think of past training, sports and even physical jobs I’ve had, and of my HR recovery rates and breathing rates etc, I don’t think it is a fitness issue tho there might be some kind of training adaptation that would have an effect. It is consistent with my tending to run hot (I’m not over-insulated) whenever I’m active. I’ll get through a lot of water and food but I’ve no problem with all day efforts and big hill days despite being ostensibly in HR “Zone 5” for most of the active time. It's like my gearbox doesn't have overdrive, or even 5th, but is happy to rev away all day... 

Anyhoo, I’ll go back to pondering, Thanks for the input.

In reply to Basemetal:

That doesn’t sound hard enough for. proper Max Heart Rate Test.  

You should hit, or be close to your Max, when anaerobic - ie. when consuming more oxygen than you can deliver to your muscles.  For most people, this can only last 1 to 2 minutes.  Elite athletes can maybe hit 3 minutes.  How long can you hold your breath for?

Even back when I was at my fittest, I’d be in a mess for a couple of days after doing a Max Heart Rate Test - as evidenced by how I felt and how long my Resting Heart Rate would take to return to normal.

There are plenty of instructions online on how to do a proper MHR Test but a 90 minute ride won’t be one of them.

Nowadays, I like to use zones that are relative to my Lactate Threshold.  I measure my Lactate Threshold every couple of months or so, using a feature of my Garmin.  It won’t be as accurate as a proper test in a lab but it works for me.

In reply to Basemetal:

Out of interest are you standing up on the hills or sitting, standing easily puts 10+ bpm on my heart rate. 

In reply to summo:

Yep. Standing quite often for the whole max effort hour too.

In reply to afx22

Thanks for that... I'll look some more, I was following a set of instructions (well, two sets merged) for LTR and MHR. But you know what the internet is like....

In reply to Basemetal:

That'll be part of your heart rate increase, all those upper body muscles working too, compared to sitting. There's always debate about sit/stand, efficiency, long shallow hill, short steep etc.. 

In reply to summo:

I don't think it was a factor as I stand up routinely - to change muscles, stretch out aon the flat and on long hills and for  short steep hills. My thinking was that I hadn't really seen an increase over what I expected... (177 v 175).

In reply to afx22:

The idea was really to undertake an LTHR test -the measured 60 min effort in the middle - and that felt like a Time Trial. The MaxHR I was trying to get from really pushing the hill repeats immediately after and while not recovered from the TT bit. 

I'd confirm going anaerobic on the hill repeats. I might not have been clear - Sprinting uphill as hard as I could, I saw my HR climb over about two minutes and then stabilise for a minute and a bit at the 177 reading. Then it started to drop a few beats as I ran out of juice. On the second run I felt I didn't have anything in the tank and couldn't get all the way up, nor reach my earlier speed or HR. I'm no athlete of any kind, I can hold my breath at rest for 2 minutes without hyperventilating, and about 3:00 with. In my twenties I could do 3:40. 

Why so long to recover? This is where I think I'm missing something. Is MHR a level that requires extraordinary measures to reach and days to recover from? 

Here's Cycling Weekly's MHR Test protocol...

"To ascertain your maximum heart rate accurately, you’ll need to carry out a tough test. Ride four times at maximal effort to failure up a long, steady climb, the idea being that you will hit your maximum heart rate on one of the latter of the four ascents. Once you have found it, you can calculate the percentages from the training zone table accordingly."

From https://www.cyclingweekly.com/fitness/training/training-zones-what-are-they...

I only managed two runs, but they were immediately after the LHTR test. 

From the Same Cycling Weekly Page (linked)..

"Complete a similar 30-minute time trial effort, but only begin recording your heart rate for the final 20 minutes of the sesson. After recording your heart rate for every minute of the testing period, working out the average of these results will give an estimate for your lactate threshold level."

I'm taking the 60 min HRav as an approximate  measure of LTHR. Unfortunately I can't extract the last 20 minutes' average as my Polar Monitor only gives one overall Average fig, but I'll redo my test and just measure the last 20 to see what the results look like. From memory I was looking at fairly consistent numbers throughout so don't expect any surprises.

Does that make more sense?

In reply to Basemetal: I've thought about this some more, and I think this is a very common phenomena amongst more 'ahem' , 'experienced' athletes.  It actually begs the question why do you want to get your heart rate up,? What do you want to improve?

Bear in mind the common phenomena that a lot of people have a 'max' heart rate running that is higher than max that comes from cycling as it's more intense, more painful, and most people don't have the power to get the cycling max over the threshold.  If you never do much in the way of hard intervals you'll fall in this category.  Similarly, and my background is running, I used to go on club nights with a bunch of old geezers who would hammer every run, to a point, but couldn't ever get there speed any higher if you put them in races as all they did was level 4... no intervals , no easy days.

I think you're there. 

Observation - 'in my 20s and 30s my HR would routinely sit at 180 when walking uphill, even when I was at my very fittest'.  Not surprising really?.  My max at 30 was 205, resting pulse 38. , so 180 is 85% of max which isn't far off what I'd expect walking up a big hill with a sack on if I was pushing

Re. other points - why base training zones on max, not threshold.. well basically threshold varies a bit through the year depending on what phase of training you're in, and some people do training above their threshold.   When you get to elite levels then the numbers people sometimes look at are min, max and threshold, and speed.

In reply to JohnDexter:

Is this still a thing? I remember trying it about 18 years ago when I started training seriously. I then went for a proper test at a sports clinic and found that  220- my age put me out by two full zones.

If the OP used this formula he'd be riding in zones 6 and 7.

E

In reply to JohnDexter:

You really need to find your own MHR. These age based formulae are not very accurate. I am lucky enough to live at the top of a lane that is a mile long and has a gentle gradient with a couple of short, but not excessively steep sections. I ride around for a few minutes to warm up then start at the bottom of the lane and try and ride as fast as I possibly can until I get home.

I am 66 and using the data from the above test my MHR is 185. I can maintain a heart rate of 150-160bpm for a very long time. My resting heart rate is 60bpm.

In reply to Basemetal:

No great insight to offer other than I find the same thing; I find it almost impossible to exercise at Z2 intensity - decided to stop worrying about it and just use the principle of making sure anything that is supposed to be an 'easy' run/ride I finish feeling I could repeat it immediately if I had to (borrowed from Real Science of Sport Podcast).

In reply to Enty:

I think they are roughest of guides, a bit like bmi being next to useless for someone relatively muscular and in good shape. 

There's no substitute for going out and doing efforts until you feel sick, then doing one more! 

Thanks for the input guys

In reply to wbo2:

I'm not trying to get my HR up, but to figure out why I find it difficult to cycle with a lower heart rate, as in Zones 2 or 3. The suggestion I've been pursuing is that my MHR may be higher than I think it is so my Training Zone table has been set too low. Trying to find my MHR will be an objective for a bit...

One possible short cut occurred to me - I could assume my MHR is 15% higher than I think it is (or that I've seen so far) and just redo my Training Zone Table accordingly, then cycle happily in the new Zone 2 & 3 for recovery and endurance days!

(The 15% fig comes from watching this fascinating video-(can you believe this is a 50yo speaking?!)...   youtube.com/watch?v=Xgs1fOeDQf0&.  ) 

In reply to Basemetal:

Think of it like this.  Imagine the 100m final at the Olympics…

In order to achieve their maximal potential, do you you think the competitors either;

a. Tapered in the run up to the event, slept well beforehand, warmed up, then raced?

or

b. Ran the 10k as fast as they could, then straight onto the 100m?

In reply to afx22:

Which of a or b would reach the highest HR?

I've been think about HR as the physiological response to demand (which can therefore go up even when performance goes down). Then a max MHR test isn't looking for max output or performance, but simply peak revs. 

In reply to Basemetal:

It’s difficult to ride in Z2 because you are only putting out 50-75% of your threshold power and unless you’re an elite athlete, this is not going to be enough to move you very fast. Just look at the gears on your bike, pros run pretty much the same size chainrings as are fitted to on an off the peg bike, but may be producing twice as much power, us mere mortals ought to be running chainrings with half the tooth count.

To get the benefits of training in Z2 I have to ride in a very low gear with correspondingly slow speeds. It’s boring but it gives results. I can now ride up a local cat 2 climb at the same pace as last year but with my HR 10bpm lower than last year  after switching from smashing every ride to polarised training, 2-3 HIIT sessions a week, all the rest of my riding in Z2 or Z1 recovery( for me that’s a HR under 119bpm, and riding at a laughable pace)

In reply to Basemetal:

There are many factors outside your power output on your bike that will impact your heart rate; body versus air temp or cooling, hydration, caffeine, food, tired muscle from over training versus fully recovered muscle etc...

Your heart might be working hard cooling you down, digesting food or drink, enjoying a caffeine or sugar spike and helping your body recover from your last session before it even takes into account supplying your muscles with extra energy and o2.

In reply to Jon Greengrass:

It's pretty hilly where I live, but have a relatively dull out and back route that avoids them for sessions where I don't want to work hard. It's tedious, but it's akin to the recovery run or easy session, where you just go at the pace that keeps your heart rate down. Using HR monitors for nearly 30 years and I've spent most time using them to slow down sessions rather than speed up or work harder. 

In reply to Basemetal:

It’s (a).

There’s a correlation between heart rate and effort.  The harder the effort, the faster your heart has to pump to get oxygen (via blood) around your body.

In reply to afx22:

I don’t think you’re looking at it the right way. While a heavy training load over a few days would dull your max heart rate, in my experience doing a long-ish hard effort with a max effort at the end elicits the highest heart rate. A single max effort on its own won’t. As Basemetal says it’s about demand. 

In reply to Yanis Nayu:

There’s different systems that you can place demand on. If you try to do a max heart rate test after a hard hour long workout with a reasonable anaerobic component, then muscular fatigue will be your limiting factor, not heart rate. You might see a very high heart rate, but it’s almost certainly not your max. 

You’re right that a single rep won’t do it either, but that’s why every protocol for a max heart rate test has you doing maximal repeats and not single efforts. 

In reply to Yanis Nayu:

I wasn’t suggesting a single attempt, or even a specific method of what to do.  I was trying to point out that I think doing too much before a MHR Test would likely impede the result.

I tried these 'revised' figures out on a different 24 mile hillier circuit and found they matched my perceived effort much more closely.

Previously HR Zones based on 175 MHR were (1-5) 88,105,122,140,158 and I was apparently in Z5 a lot and Z4 when cruising, and averaging 154 on longer runs where I'd expect to (have to) be in Z3.

Revising to a supposed MHR of 200 (for round figures), the Zones become 100, 120, 140, 160, 180 and much better reflect how I feel. Riding just under 140 gets me into the previously elusive Z2 and I can do it on the level.

They'd also suggest I'm not reaching Zone 5, which, if I'm honest is quite credible. If I presume that the 200MHR is just a little high I might just be sneaking into the highest zone in practice. 

The discussion has turned my thinking around and pretty much solved a long term mystery for me, so thanks for bearing with me and all the input and ideas. (anybody watch that video?)

In reply to Basemetal:

Brilliant video - thanks!

Will give his method a go sometime - but not necessarily looking forward to it...

Will report here if I survive!