Yes. This is typical of many athletes. And, yes - crank up the fan. Heat could be causing this.

You might also have your FTP set too high, but if you are able to do 20 minute intervals, you are probably set at a good number.

---

------------------------------------------------------------------------------------------------
New Training/Racing Log - http://www.earthdaykid.com/blog --- Old Training/Racing Log - http://colinlaughery.blogspot.com

well, I just tested and my interval was exactly at my ftp, or my estimated ftp based on 20 minutes. I hope these help, they are not much fun

jroden wrote:

I did a 20 mins interval the other day at my current FTP and held pretty steady output, but my HR came up a lot in the last 1/3, maybe 7 beats. Is this typical or related to my needing to crank up the fan?

it's called decoupling.

http://home.trainingpeaks.com/blog/article/aerobic-endurance-and-decoupling

i think i did the math right:

300 / 159 = 1.88 (first half)
300 / 165 = 1.82 (second)

remainder = .06

divide remainder by first half = .03 or 3% decoupling, so decent according to that article.

Thanks, I learned something

What I'm wondering about is the tendency for the HR to zoom up to 167 in the last few minutes and if that's environmental or fitness and if I should modify the workout or just stick with it as is.

math seems about right. i've never done it myself, i just look at the segment in training peaks. it could be environmental, but that doesn't explain the spike. it's probably mental. you see the light at the end of the tunnel and get excited.

and yeah, 3% is great. that might suggest it's time to retest because your ftp has gone up maybe. that's just my guess though, i'm not an exercise physiologist, and i don't usually stay at holiday inn's either.

no no no, i just tested last week and I have zero desire to do it any time soon, it was the first time in a few years in fact. Oddly, the factor I pulled out of my ear was within a watt of what I tested.

I find these intervals difficult mentally, maybe I have a weak mind.

i guess that makes sense, hence why i'm not an physio. i guess being able to hold the interval with minimal decoupling is the reason it's your ftp! lol derp

Was the goal of the workout to hold that FTP number come hell or high water?
Or was the goal of the workout to train a particular level of stimulation?
Many people do their workouts by zones- either power or heartrate or both.
This allows you to work into it a bit and not assume that you are going to have your best day every time out-

the first one with the "high water" involved. My plan was to do the 2x20 once a week around my ftp of 300, then do some shorter intervals of about 8 mins at a bit higher like 315-ish then something at v02 so like 335 or so for 3 mins. Then on the other days take it nice and easy and get in a longer ride once a week, see how it goes.

I used more of the "sweet spot" earlier in the winter, but figured it was time to throw another log on the fire

I think your concept is fine, but using rigid numbers is not always the way too go.
FTP can be quite manageable one day, and busting a gut on another day.

So and FTP workout could be as little as 273 watts for you and still have all of the benefit- 273-315 to be exact.

I find it beneficial to start a bit lower and work up if I am having a good/great day. Rather that trying to hold a high number, and then having heartrate decouple or having my legs unravel on me-

Training ZonePurpose%FTPZone 1Active Recovery< 55Zone 2Endurance56-75Zone 3Tempo76-90Zone 4Lactate Threshold91-105Zone 5VO2max106-120Zone 6Anaerobic Capacity121-150

I can buy that, I'm sort of a lazy trainer and was trying to push these a little harder so I actually improve. I seem to do "sort of uncomfortable" work and not get much better, though I'm 55 so perhaps that's a factor too.

One day at a time I guess.

But hitting them harder does not mean that you get more out of it or improve more quickly or reach a higher level.
In fact hitting them harder may be too hard on certain days. Or not hard enough on other days.
The minimum is a passing grade-
Age shouldn't matter either- Your zones are your personal zones.

Actually, that's a side benefit of doing regular long intervals like 2x20s, as you get better at them is a pretty good indication your FTP is going up. So if you know what th is session feels like relative to a recent FTP test, when a session of similar perceived effort happens at a higher power, you can make an estimate of your new FTP.