AI FTP detection and HR during TR workouts

I love to use AI FTP detection and think it’s a great feature. My question is this: I am able to complete so far all the workouts at my detected ftp (including 2over/under days so far), however my HR tends to creep up very high (97-98% max) especially towards the end and doesn’t really come down that much during the “under” part of the workout. I think my ftp is set too high however since I can complete the workouts is it best to leave it as is or is this just messing up my zones and the specific adaptations being targeted? (I’m on low volume sweet spot base 1 right now). I am marking the workouts as “very hard” which is continuing the keep me progressing.

I should also mention that this AI detection is largely based on outdoor rides since I’m coming out of summer.

  1. End of over or end of workout? If end of workout this can be two-fold: FTP or bot enough cooling. Especially with longer efforts not enough cooling can cause a lot of HR drift. 97-98% hr max seems a lot but I had those values with longer (around 20min) o/u efforts, especially with high values of under parts (95-100% FTP).

  2. Amout of hr drop is very correlated to aerobic fitness and value of under. The fitter you are the faster hr drop will be. Of course value of under part is also important. The sweet spot of lactate clearing is around 90% of FTP. If under part is close to threshold whole workout is way harder and more demanding. The obvious remedy is more volume and longer z2 rides. The steady threshold where total interval time is done close to your TTE (time to exhaustion) is also helping tremendously with aerobic engine and working on those slow and fast twitch fibers. This type of workout works great done just under FTP (95-98%) - like 3x15, 4x15, 2x20, 3x20 etc.


Since your able to complete events I wouldn’t worry to much about your HR, it’ll naturally creep through a workout but your max is probably marginally higher than you think.

FWIW my last session was an under over, and after the first over my HR only comes down slightly in the subsequent under. Your HR response seems perfectly normal to me.



Thanks for your reply. End of workout i was meaning for very high HR however it is relatively high after each interval. I’m doing earlier progression levels right now so the ones I’ve done are 9 min long 95%/105%. I will be progressing to longer ones soon so perhaps that will be the moment of truth. I also could probably do better with cooling during my indoor rides. The kind of workout that you mentioned at the end is interesting and i don’t think I’ve seen many of them on TR. Most of the longer intervals are in sweet spot which is a slightly lower intensity.


They should be pretty straightforward. They balance on the thin line between over/over and under/over. Given FTP can vary day to day and PM is around 2% we have a lot of variables that can go wrong.

  1. Do them by feel, not in erg mode. There is nothing magical about 95% or 92% on under or 105% over, only mental aspect. And this way you can adjust intensity. Yes, I know progression levels etc. But as a training stimulus - the same thing. Only that by lowering under you can do more work, and more work > intensity in case of Z4 and below.

  2. We returning to cooling - as much as possible.


Either you haven’t reached your true HRmax or you’re training too hard, especially still being in the base phase. Sounds more like VO2max session.
Nothing wrong with dialing intensity of that workout or your FTP down. You’ll still get the benefit and not dig yourself into a hole. Been there, done that.

Many of us would even prefer other style of O/U workout but that’s another debate/thread. (You can look it up or look TR team for example 3x20 @90/115% OU…


Thank you. This is helpful.

Thank you. Yest that makes sense.

I think a more important question is, “Does your RPE match your HR?”

If not, as others have mentioned, your max HR is probably not accurate.

If it does match, I would use the survey to mark them “very hard” and see what AI adjustments are made.

Good luck🤘

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What’s your cooling setup? You mentioned it could be improved.


Welcome to the TR community!

I think your FTP is probably where it should be if you’re getting through your workouts. I’d like to reiterate the point that @jarsson and @Jordonp86 mentioned about cooling – it can make such a huge difference when training indoors!!

Something like a blower fan or industrial fan would be worth looking into. It might sound like overkill, but it seriously makes an incredible difference.

There is certainly a transition period you may undergo when switching from mostly outdoor riding to mostly indoor, but you should be able to do the same power outside or on the trainer. Proper cooling is key to being able to hit your power targets when riding indoors.

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Haha I workout in my bedroom (small apartment problems lol). An hour or so before my workout I usually turn the heat off if its on and open the window. When I work out I have 2 small fans that blow on me. It usually is cool enough at the start however the room heats up quickly and I do sweat a lot. Sometimes I get light headed after so I’m fully aware that I’m probably not hydrating adequately either. I am working on figuring out the right formula of solutes and water for indoors still. (I have it pretty dialled already for outdoor riding).

I think I figured out the main issue. My AI detection is based on my outdoor rides which I was doing a lot of volume but no structure. When I switched to low volume indoor rides I seem to have lost about 10 watts off my FTP this past month which would mean that it is now above where it should be set. I expect next time I’m due for an AI detection that it will lower my FTP to where it should be. Not sure how you lose that much in a month but it appears to have happened. I know this as I did a long (1 hr 20min) climb again that I had done before and at the same HR my watts were down by 10. I realize there are a lot of variables in play but all signs point to a definite reduction in power.

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FWIW my HR is pretty consistent at various efforts, across a fairly wide range of temperatures. And personally I also see a drop in fitness when hours are cut back, although some of that can be reduced by carefully picking certain intense workouts.

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This is not sufficient for cooling. You need high airflow fans like Lasko (carpet type fans) mentioned numerous times on this forum (search fan recommendations on the forum). For reference, I have 2 Lasko fans (1 pointed and my legs and 1 at my torso) and 2 small fans at my face/head. Yet I still drip sweat for anything above z2 in a cool basement.

I’m a heavy sweater and used to have these same issues as well as feeling wrecked after workouts. I thought it what just me. Eventually after being so frustrated for years I got a sweat test (Precision Hydration). Turns out I lose 1,100mg of sodium an hour. I used to take in about 400mg an hour so after a couple hours of training/riding I was way down on sodium that only compounded as the hours continued.

Not only am I a salty sweater, but also a heavy sweater. I found I require 1L of water an hour during normal temps (70 degrees Fahrenheit) outside and adjust up/down based on temps and cooling.