Functional Threshold Heart Rate query

[Jackohelp]

I have a query regarding Functional Threshold using heart rate and not power.

I carried out the britishcycling FT HR test exactly to the letter including warm up exactly as detailed and 30 min full out measuring the average over the last 20min. My result was 163bpm.

Now my query: My understanding is that the FTHR is the threshold at which you can maintain for 1 hour or the line between aerobic and anaerobic.

So why the 30 minute test and not some calculation to reduce the average obtained over the last 20 min. I am basically questioning whether I could indeed maintain 163bpm for 1 hour.

Could someone explain?


https://www.britishcycling.org.uk/zuvvi/media/bc_files/sportivetrainingplans/THRESHOLD_TEST.pdf

 

[Citius]

It's not the HR number you have to maintain - it's the effort level. Your HR will probably fluctuate and/or diminish over that time. The number that a FTHR test gives you basically enables you to set your training zones. Just use it as a guide, rather than a maxim...

 

[Joshua Plumtree]

But unless you make the necessary adjustment you're setting your training zones to this 30min effort and not your FTHR. I thought the idea was to knock between 5-10% off this figure to give you a workable FTHR. But I could be wrong.

 

[Jackohelp]

Yes I realise that, I felt my effort was consistent and my average came out at 163, each time I went over i did struggle more. They do say not to reduce the HR figure as it is likely to stay consistent. It just seems a bit high

"Once you have your average heart rate or power figure then you can input them into our calculator which will give you your training zones. Nothing is subtracted from the heart rate value, as this parameter would normally remain stable for the entire hour. "

 

[Jackohelp]

I put a link to the test in the first post straight from the British cycling site

 

[midlife]

Are you trying to calculate V02 Max from your heart rate?

Shaun

 

[Jackohelp]

Not really, the calculator on the site did it automatically. I'm sure there is an element of inaccuracy, just interested to know how much and others views on the topic

https://www.britishcycling.org.uk/membership/article/20120925-Power-Calculator-0

 

[Joshua Plumtree]

Looked at the link. Appears to be a 20mins test, not the 30mins you've done.

Because it's heart rate, which, as Citrius has said, is not a particularly reliable guide, it could be that between 30-60 minutes, although your power will drop away, your heart rate will remain fairly constant. After a certain point, the body has to work harder to maintain the same speed. Think they call that aerobic decoupling.

If you've put in the data, what figures are your training zones set to according to the B.C. model? Perhaps their calculator is already programmed to reduce your HR number by a certain percentage in the calculation. You should be able to work this out by the lower and upper ends for your training zones, especially the threshold zone.

 

[123456789]

Jackohelp

I also did the same test very recently as you can see from my other thread on here and have read a lot on this in answer to your question as to why you take the last 20 mins I found this:

"Why take only the last 20 min avg of the test? Cardiac drift. Your heart rate takes a while to get up to speed with your effort, usually 5-10 min. To accommodate this, you start your test early, to get your heart rate to up near the threshold and give a better indication of the LTHR."this was from here: http://mtbcoach.com/training-sessions/lactatetheshold-heart-rate-and-ftp-test/
Everything is an approximation though. I hold 165-174bpm for a ten mile TT and doing the FTHR on the turbo I had 168-173 for the last 20 mins. inputting my result into zones and then looking at the description of rate of perceived effort I can say that there was a real correlation, except with regard to higher zones but then HR is meaningless on a very short sharp interval anyway.

Could I have held that pace for another for another half hour? the answer would have to be no, however I would imagine that my heart rate would have remained the same or maybe even higher for the next 30 minutes despite slowing the pace. For an effort longer than one hour I think I would have to keep my heart rate lower and I think that is the point you are establishing an approximation of your heart rate for a perceived effort and by performing the test you are saying well for a Zone 4 ride my HR should be between here and here and my rate of percieved effort should feel like this this is a rough guide as HR can fluctuate.

I will repeat tests on a regular basis both on the turbo and on the road so over a period of time my approximations may become more accurate however it will always be like archery one day my HR and RPE will be on the bullseye other days it will slip into the yellow.

Apologies bit of a rambling but hope this helps

 

[adamangler]

from my limited experience you can use either ftp on fthr and should be in a similar ball park. watts is going to always be the most reliable

but if you can hold 165hr for 20-30 mins you could probably hold it for an hour but with a drop in watts

thats why if you have an ftp of say 200 for an hour, you will probably find if you strart out at 200w your heart rate would be say 160 to start with but would rise over the hour to say 170 as you try to hold the wattage

where as if you went by heart rate and hit 165 straight away you might find your power starts out at 220 watts then end up at 180 watts giving you the average of 200

Its better to go with watts because that cant change whereas lot of things can effect your heart rate but its still not a bad indicator

so to answer your original question, you dont take 5% or whatever off the heart rate as the heart rate stays the same, wheras if you were trying to hold a wattage of a 20 min test for an hour your heart rate would rise and you would blow up, hence why you take the % off the 20 min wattage max test.

my 20 min ftp hr tends to be about 165 on the turbo an i know for a fact i can hold 165-170 hr for an hour as ive done it

 

[Jackohelp]

Thanks all. Adamangler that is interesting so maybe I'm not too far off. I'll keep testing. The power meter is too expensive! I'm just going back on to do some zone 3 training with 3 minute intervals pushing into zone 4

 

[adamangler]

Power is great but You'll be surprised what you can do by feel once you get used to working in heart rate zones you can take your eyes of the hr and stay in the zone by concentrating on your breathing.

 

[Cube]

I used to train with HR but just fond it so irratic but then that is all that was around but now with power meters what a difference. I couldn't go back now!