HR TSS Estimate

Has anybody else noticed you can enable a TSS estimate from HR data? I know it’s been asked for a lot but haven’t seen an announcement or thread about it.

On the webpage, go to your account and then TSS estimation. Enter your max cycling HR, birthday and then select if you want this estimate for all rides, future rides or you decide per ride.

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I cannot find this setting on my account.

Shouldn’t this be calculated from LTHR instead of max?

Yes, I use this all the time for commutes on my single speed, it’s okish.

I think it’s part of the AT beta. I had a popup about it following an outdoor ride on my MTB which doesn’t have a power meter.

That raised a bug (for non-USA users) in that my date of birth was in dd/mm/yyyy format and it crashed the code. So if you don’t use the US mm/dd/yyyy format then that’s something to be aware of - just put 01/01/yyyy since being a few months out isn’t going to make any difference to the usual HR algorithms.

The maxHR value was also odd, 202, I think it picked up an erroneous spike in the HR data rather than a value that existed for a few seconds. I’ve had Garmins give weird readings when near railway overhead cables for example. 202bpm would have me heading to the nearest cardiac unit!

I have been using it, it seems reasonably OK for normal rides but for recovery rides/very easy rides the numbers seem to be quite high.

I also have intervals.icu connected and they explain how the HR TSS calculation works there - they build a regression model using your rides with HR and power to estimate TSS for rides without power.

I did a hard ride Saturday and Intervals and TR were within 1 TSS of each other (329 vs 330), but last night I did 1h45 easy and got 47 from Intervals and 90 from TR, which is a big discrepancy. Based on RPE, average HR, time in HR zones etc etc. I am much more comfortable with the 47. 90 seems a drastic overestimate. Strava relative effort was only 31 for the ride too, usually when I have power the HR based relative effort and TSS are rather closer together.

Fortunately, you can still set the TSS the old fashioned way so it’s no big deal really.

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I’ve only been in the Beta since yesterday but have checked a few outdoor rides utilising the new HR TSS estimate and have also found it to be high.

I sent a little explanation to TR Support today:

…you appear to have an HR based TSS estimation for outside rides now. I have been using the Strava/Stravastix/Elevate TSS estimation for all of my outdoor rides. However, I have just checked a few using the TR HR estimation and there seems to be a considerable discrepancy.

For example. This mornings outside ride got 38 in Strava, but 62 in TR. And a previous one got 39 on Strava, but 64 in TR. Comparing this to my indoor trainer rides, this doesnt add up. For an hours VO2max workout I am getting approx 60-70 TSS and for an hours endurance, around 35-45. Based on HR, and endurance ride is about Average 130 HR whereas a VO is average 155 with a peak of 175 ish. Therefore for an hour outside, where I am averaging 130 and a peak of 155, you would expect it to come in around 40 TSS, not 62?

Bit rambly but you might get the idea :blush:

To be fair, one of the known AT issues is that the HR TSS isn’t working correctly, so could be related to that…

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Ah, I missed that on the AT page previously, thanks.

I recently got into AT too and must have missed the TSS announcement.

From the comments above, it seems to have the typical TSS from HR issues meaning it’s a ballpark estimate but not perfect. Hopefully over time AT will learn and improve the calculation.

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