Hi @david
Some time ago I got email that stated something like “Your threshold HR has increased by…”. I wonder if it’s possible to get that value on demand? Eg I’ve ridden very hard and got new FTP estimation and I’d like to know how it looks like on HR perspective…
Garmin estimated it very high and I’d to know intervals.icu value as I follow single source of truth 
Dominik
Tx. Intervals.icu uses 98% of your best 20m or 100% of your best 1h heart rate for LTHR estimation. You can read your best 20m and 1h HR on the activity HR page:
So my LTHR for that ride is 0.98 * 162 = 158.76. It doesn’t really make sense to use it unless you went absolutely flat out.
to tag onto this topic, can i reset the thresholds ?
I had an accident and know my performance has dropped dramatically. it would be nice to see my lthr climb back up.
hi,
in the book of Joe Friel he writes that you take 95% of your 20m heart rate. why does intervals calculate it with 98%?
He actually says do 30 minutes, and take the average of the last 20 minutes. The most important point is that it’s an estimation.
Setting Heart Rate Zones (Running and Cycling)
Step 1 . Determine your lactate threshold heart rate (LTHR) with a short test. (Do not use 220 minus your age to find max heart rate as this is as likely to be wrong as right. This is explained in detail in Total Heart Rate Training.) This LTHR test is best done early in the Base and Build periods.
To find your LTHR do a 30-minute time trial all by yourself (no training partners and not in a race). Again, it should be done as if it was a race for the entire 30 minutes . But at 10 minutes into the test click the lap button on your heart rate monitor. When done look to see what your average heart rate was for the last 20 minutes. That number is an approximation of your LTHR.
Note: I am frequently asked if you should go hard for the first 10 minutes. The answer is yes . Go hard for the entire 30 minutes . But be aware that most people doing this test go too hard the first few minutes and then gradually slow down for the remainder. That will give you inaccurate results. The more times you do this test the more accurate your LTHR is likely to become as you will learn to pace yourself better at the start.
thanks for the answer.
so if you do just 20 min all out effort you take 98% (due to the hr raising at the beginning)
if you do 10min hard then 20 min all out you take 95% (due to the hr being elevated in the beginning)
is my conclusion right?
for sure it is an estimate but it just confused me that there are two different values (98% and 95%).
Intervals takes this value from any workout/training/ride and not specifically a test.
If during a race you have a 20 min period with an avg HR of which 98% is higher then your actual LTHR setting, Intervals will warn you that your LTHR has probably increased and asks you if you want to accept the new value.
In a test, you follow a typical protocol. Here you deduce values from real life riding.
In his blog, Joe Friel says take the average of your last 20 minutes of a 30 minute effort. So no % of the average.
In his book, Training Bible edition 3, the 20 minute test he talks about is Dr Andy Coggan’s test, which is less 5%; he specifically mentions “Dr Coggan’s test”. I looked at the Training and Racing with a Power Meter, and I couldn’t find the specific reference to LTHR. Also looked at Fast after 50, and he talks to the Dr Coggan 20-min test.
However, both tests recommend a good warm up (up to 20-mins) with some accelerations (RPE 7) from as long as 2 minutes to a few seconds (Friel) and the 5 mins at about 106% of FTP (Dr Coggan). The estimated LTHR is then -5% for 20-min and average HR (last 20-min) for the 30-min test.
ok! thanks! always new things to learn!
