Ride data using HRDM vs. Power

My powermeter’s battery died before today’s ride, giving me the opportunity to use HRDM for the first time. I did a similar ride on similar terrain two weeks ago and would expect the metrics of the two rides to be roughly similar. Unfortunately, they were not. Here’s some of the data:

Today (HRDM) 117
Previous (Power) 185

Average Power
Today (HRDM) 52
Previous (Power) 81

Today (HRDM) 40
Previous (Power) 77

As another comparison, Strava’s relative effort for today’s ride was 108 vs. 119 for the previous and the average power for today was 92 vs. 87 for the previous.

The HRDM metrics seem off to me. The two rides were 35 vs. 32 miles and 2700 vs. 2500 feet of climbing. My perception of the efforts is pretty similar, maybe today being the slightest bit mellower.

I am away from home and won’t be able to get power up again for a few weeks, but these HRDM metrics seem off and can’t be trusted. Can they be overidden? Do they make sense to more experienced users of HRDM?

I have zero experience with HRDM, but I assume you have set the HR parameters in your profile correctly.

With that, if you have never used HRDM, I’m not sure - but I suppose it would - if Xert looks at your history from before that first time.

Second, I expect that Xert does define some sort of HR zones, but if they are too broad or general, they may not reflect your own zones.

For instance, since most of my training is Z3/Z4 (sweet spot), my HR has adapted and is mostly in Z2, so lower than one would expect.

You may have a similar issue.

Third, as to overwriting, I guess your best course of action is to add a manual entry to the planner, to make up for the ‘loss’ of XSS, so that XATA will not calculate your deficit or surplus incorrectly…

How much HR with cadence history do you have on file?

Every ride has HR, cadence, and, until yesterday, power.

To clarify, that’s over 140 rides.

I haven’t use HRDM yet either but I noticed this setting –
To fine-tune the algorithm to better reflect your current resting and maximum heart rate values, disable Auto-estimate Heart Rate parameters and key in your resting and maximum heart rate values directly.

If you already tried that then I suggest contacting support@xertonline.com and have them take a look at your data.
Perhaps the algorithm needs tweaking. :slight_smile:

Hard to say without seeing the comparison of HR between the rides? What were the averages, maximums, time in different HR zones…? how long were the rides (time)? HR can vary even if RPE is similar, due to other factors (temperature, hydration, fatigue etc)

I don’t find it too bad in general, especially for more steady endurance rides. It can understate intensity a little, I guess due to lags in HR response. I also found it less accurate with a cadence sensor on MTB rides (contrary to guidance to use a cadence sensor… apparently it only helps for ‘similar’ ride types). In that case it was over-stating intensity, I guess perceiving the sometimes sporadic cadence of MTB with actual high power efforts.

As @ridgerider2 suggests, make sure the max and min HR parameters in your profile are accurate.

You can manually input XSS and focus via the Planner tab as @Cyclopaat suggested. Best way would probably be to flag the ride first, then manually input XSS and focus for that ride via the planner. That way you don’t need two entries.

We actually don’t use any sort of “Zones” for estimating your XSS & Focus. We use your historical data to identify trends between Power, Cadence, HR, and XSSR. As @wescaine already mentioned, HRDM work really well with sub-maximal/steady state efforts, but it becomes increasingly more difficult to extrapolate estimated power/XSSR once the efforts become more stochastic. HR derived metrics will inherently be less accurate than power data, since HR is far less consistent (HR is sensitive to ambient temp, sleep, stress, hydration, etc,. - once again, already acknowledged by most of the users above here).

For the recent ride average HR was 126 and max was 168. Just short of 3 hours of riding. 20% of the ride was zone 1 and 2.

For the earlier ride, average HR was 130 and max was 197 (which is interesting because my max is really around 181). Just over 2.5 hours of riding. 30% of the ride was zone 1 and 2.

Still hard to say given the variables… both were actually intense rides given the low time in lower zones (even if not technically used that way by the algorithm or Xert more broadly) for different durations with different intensities… as mentioned I think it can underestimate work done for higher intensity rides, but up to you whether you want to overwrite it…