UKH

I’ve been using various GPS running watches for about 8 years. My current model is a Garmin FR235.

At the end of each run it tells me that I need a certain amount of recovery time, this is usually between 24 hours and three days. As someone who runs most days and sometimes twice a day, this information is ignored.

Has anyone any idea what it is based on? Can I disable it? I like the watch, but this is a bit annoying.

I think it’s an algorithm of heart rate/duration, but I’m not sure. 

Google is your friend. 

https://www8.garmin.com/manuals/webhelp/forerunner235/EN-US/GUID-EAC8F156-A...

I’m sure you are right. I don’t think the heart rate monitor is particularly accurate, but even so it is incredibly conservative. It does make me wonder about some of the other metrics that it produces, particularly VO2+ Not that I pay much attention beyond distance and pace.

I love the recovery times on my Suunto from a comedy point of view. I don't use the HRM so it's basically meaningless. It prioritises speed over distance and ascent so a quick, flat 10k can count the same or more than a super hilly 40k. Plus it maxes out at 120hrs so a trot along the Mamores with a quick return down glen nevis came out the same as a BG in blazing heat.

I wonder if it's any more accurate with the HRM.

Nor me. I have a Garmin 230 which I am also very pleased with, but I consistently find the ascent measure to be dubious. I should, but haven't yet done an analysis of this, but the ascent I get for a route according to Strava is almost always less than the  OS maps site gives me, and more than the Garmin site gives me. 

I expect the occasional massive error where I am running along the coast path (I'm normally in Cornwall) and the GPS resolution can't tell if I'm jumping off a cliff and climbing back up again, repeatedly but there is a consistent difference between these three sites which puzzles me.

This last few days I've been doing some cycling with my wife. She has registered a heavier weight than me on her Strava profile (don't tell her I said that) and measures her routes with an iPhone. It consistently gives her about 5% more distance, 30% or so more ascent but about half the calories. Which annoys her a lot. I discount the calory calculations, given what Strava, Apple or Garmin know about us, and given the many variables involved (and anyway I don't care) but I am puzzled about the discrepancy in the ascent values.

Even if neither device, my Garmin 230 or my wife's iPhone has a proper barometer (I don't think I am wrong in that but correct me if I am) surely there is enough data by now on pretty much every stretch of road we have cycled along (mostly, from the evidence of this week, old guys dressed to the nines in TDF gear) for Garmin/Strava (who does it, in the end?) to really know what the ascent is, since these stretches must by now have been cycled along by many people with the fanciest GPS/barometer devices that money can buy.

So, is the ascent calculated from the data that the device we have sends in for the one route that we did, or is it done in a more sophisticated way by an algorithm that decides from our GPS data what road or path we have actually followed and then attempts to construct our ascent figure from a best possible assessment that uses data from all previous traverses of that route by people with all sorts of devices?

I don't expect you to know btw

I have my VO2 max done a couple of years ago at the University and found the figures to be very close between the lab and my watch.

The whole recovery thing is a metric beyond necessary and means that you might avoid listening to your body which should really decide if you run less more or not at all. 

The height data is useless!

Fenix 3s and FR610 previously

I use a Fenix 5 and find the recovery indication about right, I have never seen in over 36 hours, it probably means more with training status thrown in but not sure the FR235 has the full suite of Firstbeat metrics that the higher end stuff does ?

When you import your activity to Garmin connect you can tell it to correct ascent data to GPS for devices that don’t have barometric altitude.

The time counts down until it is optimal for you to attempt another hard workout. 

https://www8.garmin.com/manuals/webhelp/forerunner235/EN-US/GUID-DAC27D10-8...

I've left it switched on for comedy value. Best if (on the watch) you accidentally end your run after 10 miles while in the middle of nowhere and it tells you you'd better wait there for 28 hours before trotting back out. Would be a great excuse for not turning up to work. 

If you do that sometimes the recovery time is less when you get home (usually only an hour or so) - quite bizarre.

I did some googling on this subject once and found that Strava does something pretty interesting if you import data without barometric height data.  They have been slowly collecting lots of data from all their users public uploads (from those devices that do have barometers) and using some averaging algorithms making this into a global altitude map. 

So...

If you're running a pretty popular route chances are they have a fairly accurate (?) altitude map for that route, and that's what your gps gets superimposed over.

If you're running on a fairly unpopular route chances are they have a fairly inaccurate altitude map for that route but they still use that and try to guess where there are gaps in the data.

and if you're running out in the middle of nowhere (where they have no altitude data at all) they revert back to some publically available data that is based on some satellite imagery which is supposedly pretty inaccurate.

Geeky stuff though...I like it.

Thanks. I do too.

That's what i thought they must be doing, given the data they have. It doesn't completely explain though why two widely used devices consistently give the same differential for ascent on frequently travelled chunks of road. By now, on such routes, I would expect that the claimed ascent would be calculated with little regard for which device was actually used. 

Which means too, if I am right, that there is little point in buying a fancy barometric device, if you only or mainly do such routes.