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VO2max decreases after long runs.

Hello, New to the forum but been using Garmin watches for about 3 years. 1st the 235 and for the last year or so the 935. Train 5 days a week, average week about 35km running, 120km Mtb en 2 (90min) weight training sessions.
Here is my question.
I have got a VO2max score according to Garmin of 52, for my age I am very happy with that. But after long runs I always seem to loose a point of this score. Yesterday for example a 19km run, ave. pace 4,45 p/km, mostly in or around lactate threshold. Was happy witj the run until I saw thst the VO2max went down to 51 and the training status went to unproductive. This happens alot when I do longer runs, is this normal? Any ideas how to stop this happening?
thanks in advance for the replys.
Gav

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0 webvan over 6 years ago

For a start going from 52 to 51 is a negligible difference, after all it's just an estimate. Second, as others have said (more diplomatically) your training is all messed up. It should be 80% easy and 20% hard and a long run shouldn't be more than 30% of your weekly mileage. Also LT is the max pace you can sustain over an hour while competing, so that's for elite runners when they run an HM, for good runners that's 15k and for the average runner that's 10k.

Based on the info you've given us you must have been completely exhausted after that these 19k@'4''45'/km and that is indeed "unproductive" ! Still that's a nice run and with some better training you should see your VO2Max estimate go up a lot and more importantly improve your running performance and race times if you're interested in that.

0 Former Member over 6 years ago

I totally agree with the last statement. Just do one long run in the weekend at lower heartbeat - in my case 135-140. Then you can run much longer without the risk of being overtrained.
Running at LT for much longer than 1 hour is not recommended at all unless you are Kipchoge...and even then...
More slow training and keeping the heavier training for shorter distances like described above

But even considering all of this, there is a point raised in other posts relating to a correct VO2 max calculation. Using the relation between pace and heartbeat is ok for determining your vo2max (as described in the Firstbeat papers) but distance should also be a factor/dimension, even when using a smoothing algorithm! I too seldom have a productive status when doing low slow runs...also, i think you do not get enough training status points for this. If you just do one or too sprints in a training, you get rewarded for that although one can infer that these one or two accelerations would not deserve this extra reward.

0 SwampyGav over 6 years ago

OK. What I was aiming at was: In weeks where you haven't done these long, rather fast runs during the weekend before, what happens to your Monday and Wednesday runs? Can you run those at a lower heart rate and the same pace?

If yes, the VO2Max calculation after the long run may be correct.

Hello Allan, Yes, If I dont do long runs in the weekends I can run at these speeds with a lower heart rate.

0 SwampyGav over 6 years ago

Gentlemen thanks for the messages, alot of good advice in there. Makes me realise that I have no structure to my training and need to make a plan. I will be trying out the 80/20 rule and the long run of 30% of weekly distance. Also try out intervals. I thought that I could just go out and push myself to limit evertytime and now starting to realise that there is alot more to it than lacing the shoes up.

0 AllanOlesen67 over 6 years ago

Hello Allan, Yes, If I dont do long runs in the weekends I can run at these speeds with a lower heart rate.

Good. That is an indication that your long, fast run actually reduced your fitness - at least in the short term. So in that sense, your watch was right.

(Your long, fast run probably still did some good in the long term, we can hope. But a long, slow run might have done even more good, both in the long and the short term.)

0 mcalista over 6 years ago

Gentlemen thanks for the messages, alot of good advice in there. Makes me realise that I have no structure to my training and need to make a plan. I will be trying out the 80/20 rule and the long run of 30% of weekly distance. Also try out intervals. I thought that I could just go out and push myself to limit evertytime and now starting to realise that there is alot more to it than lacing the shoes up.

The body has several different energy systems (eg. aerobic, anaerobic, lactate buffering), and to truly go fast, you need to work on ALL of those. But to develop these energy systems, you need to train each system individually. The aerobic system is dominant up to about 70% of MHR, so that is where you need to train to develop that system. The lactate system is best trained just below and just above 90% of MHR, and the anaerobic system is best trained with repeated short intervals above 90%.

The 80/20 rule is a simple but effective guide that helps separate out your training into different zones, but develops your overall speed and fitness.

0 webvan over 6 years ago

Right and most casual runners are going to be running around 80% MHR and getting pretty exhausted in the process with little progress to show for their efforts.

SwampyGav - with some balanced training you're likely to find your current LT shifting over time towards your AT (Aerobic Threshold) and being able to enjoy your runs a lot more.

0 gingerneil over 6 years ago

I get this, and find it a little frustrating. However, I'm not a slave to the metrics from the watch, so I'm not losing sleep over it.
I ran a 20.5 miles mix of trails and road yesterday. This was 85% at easy pace, with my HR staying in the Easy zone for most of it. I picked up the pace a little at the end and pushing into aerobic.
https://connect.garmin.com/modern/activity/3073769071
Performance condition went from -1 to -6 by the end!
I expect to get a good actual training effect from this - steady long run, good time on feet, steady HR etc. All the 'classic good things' for a long easy marathon training run.
However - garmin only gave me 3.4/0.0 for this, and my load has gone down by over 200. Going by the HR level, this is probably understandable - but the algorithms seem to give far more 'credit' for a short session at high HR vs a longer session at lower HR.
My run last Monday was a 1 hour tempo, giving 3.8/0.0 - so I can see *why* Garmin would drop the current load based on this. However, giving only 3.4/0.0 for the long run seems a little off to me, and that then skews the training load. Sporttracks gave me an 'effort' score of 150 for the long run and 128 for the tempo - this seems more realistic to me as an input into performance conditioning.
I'm now unproductive too according to Garmin!
(yes, I've checked heart rate zone settings etc).

0 webvan over 6 years ago

Yeah the FirstBeat algorithms, or at least the way they are implemented by Garmin, seem to have zero awareness of long runs and D+. In my experience, the lower the Garmin TE on a long run (or an easy run) the better for VO2Max...but of course the training load gets skewed. Honestly their stuff doesn't appear to be very well thought out and they're just throwing numbers out there that aren't really consistent. A bit of a shame but I've stopped worrying about that and keep a closer eye on the excellent metrics provided by Runalyze (it's free too) where you get all kinds of metrics, including "Marathon Shape".

0 HermanB over 6 years ago

The device can't calculate true VO[SUB]2[/SUB]max. It just estimates based on your pace and heart rate; if your heart rate rises at the end of a long run while your pace stays constant then the device may consider that your VO[SUB]2[/SUB]max has declined. This could be a real decline if you're over training, or it could be just a false temporary decline even though your actual fitness is increasing.

Analytically speaking, cardiac drift is a known and recognizable physiological phenomenon. The Firstbeat analytics engine is designed to account for cardiac drift over the course of a run. That said, things get quite a bit trickier when your overall training activities produce fatigue that isn't offset with adequate recovery.

I just noticed that cardiac drift isn't mentioned on our feature description page.

https://www.firstbeat.com/en/consumer-feature/vo2max-fitness-level/

But it is mentioned in the white paper.

One of the key features of this method is the detection of reliable periods for VO2max detection. Figure 1 shows an example of how fitness level can be reliably detected during an uncontrolled running session. The reliability detection includes both exercise mode detection and data reliability detection. There are some situations in which the exclusion of data segments is necessary for reliable fitness level estimation. These automatically detected situations are, for example, running on soft ground, on a steep downhill, stopping at a traffic light (where the speed is zero but the heart rate is elevated), or the effect of cardiovascular drift (heart rate elevation) in long duration workouts.

Source: Automated Fitness Level (VO2max) Estimation with Heart Rate and Speed Data https://assets.firstbeat.com/firstbeat/uploads/2017/06/white_paper_VO2max_30.6.2017.pdf