58 comments

  • timanderson 19 hours ago

    I have an Apple Watch 7 and a Garmin Forerunner 265. The Garmin gives me a much higher VO2Max. I have no idea which is right but one factor seems to be the max heart rate, which the Garmin calculates but in Apple Watch seems to be fixed based on age unless you set it manually. Reluctant to set it manually as it will change over time and would neeed re-calculating so the Garmin approach seems better to me.

    • iamacyborg 18 hours ago

      > I have an Apple Watch 7 and a Garmin Forerunner 265. The Garmin gives me a much higher VO2Max.

      Realistically, does it even matter? It’s not a usable metric by any means nor is it particularly meaningful unless you’re an elite athlete (and even then, you probably don’t use the metric to tweak your training).

      • timanderson 18 hours ago

        It's meant to be an indicator of fitness but agreed it doesn't make any practical difference to how you train

      • matsemann 18 hours ago

        The absolute doesn't really matter (except for bragging rights), but the trend is definitely useful if it accurately follows your form.

        Of course, a vo2max doesn't explain everything as an endurance athlete. As a cyclist it has a big correlation to FTP, but there are also different metrics to be good at. Short sprints, recovery after bursts, plain grit for multi-hour rides etc. are all different skills not shown in a single number.

        • starfezzy 18 hours ago

          The absolute value does matter for several reasons, but the obvious one that sticks out is in understanding the effectiveness of your training.

          Example: if your real max is 60, but your watch says 50, you may be wondering why hard training isn’t increasing it.

          Another example: if your real max is 35 but your watch says 45, you may misinterpret the signal when it jumps to 55 relatively quickly after a few weeks of hard-ish work.

          Plus, if the value is significantly inaccurate then who knows what else is inaccurate about it? I appreciate that Apple have put effort into making it accurate.

          • matsemann 10 hours ago

            But my point was more that if it shows 45 (but real is 35), and then you work out a lot and it shows 55 (but real is now around 45), it's still useful even though the values are off. As long as the error/bias is the same.

        • iamacyborg 18 hours ago

          You’d probably be tracking FTP or lactate threshold (amongst other things) instead of vo2max, right?

          • k1kingy 18 hours ago

            100%. Every semi-serious cyclists would be running a power meter first and foremost (heck even average joes these days because most modern high-end road bikes come with one already). Far easier to do a 20min/ramp test every so often instead of trying to focus on VO2 max.

            • matsemann 18 hours ago

              Yup, but as I said, it's nice to not focus on a single number. FTP doesn't tell how well I can recover after a hill at 120% of ftp, so even though I work on increasing my ftp, it's nice to keep in mind other aspects as well. Both vo2max, but also just how I feel when doing it, how my heart rate is during comparative rides, or even how well I'm fueling.

        • nsbk 18 hours ago

          I just focus on the trend rather than the value. Last year, after being infected by two viruses in parallel my vo2max plummeted from ~55 to 40 in a month. It correlated with how I felt, like 15 years older. It took me six months to get back to 55, and then it stayed around that value quite consistently, viruses or not.

          • formerly_proven 18 hours ago

            Similar for me, but I've also not really seen my behavior influence it too much. I clearly have better and worse weeks / months, where I might walk at 10min/km and require a 90-95 HR to do that, and worse months where I'll only walk at 11min/km and end up in the 100-110 HR range, but it's not like my exercise levels or weight or nutrition or anything would differ much between the two, they are all very consistent. Likewise when I increase cardio training I don't see any correlated change in VO2max. That also makes sense, as VO2max is famously difficult to train.

            I suspect for me and probably many others in the "acceptable fitness level" category the main factor influencing what ends up being reported as VO2max is stress, both physiological and psychological. That correlates real good. At least for me.

            • nsbk 13 hours ago

              In my experience, vo2max doesn't seem to correlate with stress. I've been stressed out for the last few weeks at $dayjob, and my vo2max has been consistent with more relaxed periods (high). How much of a variation do you perceive during stressful periods?

    • Gualdrapo 18 hours ago

      > the max heart rate, which the Garmin calculates but in Apple Watch seems to be fixed based on age unless you set it manually.

      Is it like that for min heart rate? I have bradycardia, but lectures in my blood pressure monitor go from 44 to 41

      • esquivalience 18 hours ago

        Is it possible you mean 'readings' from the monitor rather than 'lectures'?

        If so that would be a very easy translation error to make. ('Readings' and 'lectures' can be synonyms, in the sense of someone knowledgable reading something out loud.) But it could just be me misunderstanding: sorry, if so.

      • dpz 18 hours ago

        I also have bradycardia, one of the goals for having a good garmin fitness age for me is maintaining sub 46bpm heart rate. So I think it takes it into account

      • pimlottc 16 hours ago

        “Lectures” in your blood pressure monitor?

        • TheCoreh 16 hours ago

          They probably meant readings, as the cognate for "lecture" in romance languages generally means both a lecture and a reading

  • kashunstva 18 hours ago

    Although I have enough cardiopulmonary reserve to have completed the Triple Bypass in Colorado, the Apple Watch regularly registers me in a near-cardiac-transplant range of impairment; so I’ve come to mistrust its estimates. It also correlates poorly with a laboratory VO2 max ergometric test in my case.

  • LandR 19 hours ago

    The Garmin Vo2 max estimate is supposed to be pretty accurate too, but mines is wildly off.

    It also has race pace estimates for 5k, 10k, half mile etc and those are wildly off too. I think it bases these off Vo2 max, so its unsurprising. It thinks I can do a 42min 10k, that is just never happening.

    • timanderson 19 hours ago

      Experience of those race predictions varies! Mine are over-optimistic but not by that much, a friend is the other way round and Garmin continued to predict a slower time even when he actually recorded races in faster times.

      • dpz 19 hours ago

        I think its more potential, my 5k/10k are quite accurate but my half and full are quite off - which makes sense as they're the distances I train for. It also doesn't take other factors into account like running on track vs road

        • rojeee 18 hours ago

          That makes sense. If you do longer runs (and long fast runs) then your half/marathon time will be more accurate. In general, the issue with using VO2max to priduct race performance is that it doesn't take into account account running economy which is a massive factor in determining performance for longer distances. Same with lactate threshold, which has a big impact on all distances. E.g. at what point do you go from a metabolic steady state to an unsustainable state. It's the most important factor in distance running in my opinion. The threshold can be at quite a slow pace even for someone with a high VO2max if they are not doing the right training. E.g. think of someone who is excellent at HIIT and has a VO2max of 60+ but can't run a fast 10km.

          • iamacyborg 16 hours ago

            Pretty sure garmin do take other factors into account for their race predictions as they’ll update when your lactate threshold does, even if your vo2max remains the same.

            • rojeee 16 hours ago

              I think you are right regarding lactate threshold but im not sure how they factor in running economy as it's difficult to calculate. You need an accurate VO2 measurement. I guess they use HR as a proxy but in practise I find HR isn't such a good measure of metabolic output for various reasons; hills, unrelated stressors, heat, aerobic decoupling, etc.

              • iamacyborg 13 hours ago

                No one except elite athletes are looking at running economy, there are far too many confounding variables.

                • rojeee 13 hours ago

                  Well.. a crude estimate of relative running economy is pace/heart rate and tracking it over time. Seeing the number go upwards means your economy is increasing and vice versa.

                  A fair amount of people track this because it's a feature of pretty much every training/coaching app.

    • vbarrielle 18 hours ago

      In my experience, the VO2Max estimator for Garmin tends to produce higher estimates when doing quite slow runs and gradually building up speed, whereas intervals sessions will lead to a lower estimate. From reading their white paper they fit a curve to the heart rate reserve vs pace relationship, but I think they account for heart rate lag using population averages, which means they'll often think (for me at least) that I need a very high heart rate for a slow pace after intervals which biases the estimate down. If one starts slow then builds up speed gradually, the aerobic system is more warmed up which leads to less elevated heart rate. Also, keeping the run short-ish will lead to higher estimates since heart rate drift seems not to be taken into account.

      All considered, the variance is quite high which in my experience does not make it that useful to track relative fitness changes.

    • k1kingy 18 hours ago

      A lot of it probably comes down to the amount of data you feed its algorithm right. If you train a lot (70+ miles of running per week), log absolutely everything, and wear the watch 24/7 then it's going to give you far better estimates than someone who just puts the watch on to run twice a week.

    • xxs 18 hours ago

      >(It thinks) I can do a 42min 10k

      Impressive, going over 14km/h (~4m/s) sustained is no joke. Many folks would just cramp out at that point. OTOH, Garmin's "body battery" seems quite accurate for my spouse

  • cmgbhm 19 hours ago

    The apple vo2 max calculator drives me crazy because I cycle. When I do long enough walks to trigger the calculation, it’s walking dogs with frequent stops.

    The FTP calculation is also annoying because it can’t differentiate types of rides.

  • rojeee 18 hours ago

    In my experience the only way to get an accurate VO2max is to do a lab test. I'm 40. My Garmin Fenix 8 suggests my VO2max is 69 at the moment but it's actually 64 as I recently did a lab test. Other things to consider: 1) VO2max changes day to day depending how recovered you are. 2) Environmental conditions will also change the value e.g. too hot/cold. 3) You need to be running on completely flat ground to get a decent result as although some of the estimation algorithms take elevation and surface into account, I'm sceptical as to their efficacy.

    Ultimately, VO2max, whilst a good health indicator, it's not the be all and end all for running performance. VO2max doesn't take into account lactate threshold and running economy. Two athletes can have the same VO2max but quite different race results for common distances. One might have a very large aerobic capacity but very poor running economy, so metabolically, they require more effort to run at the same pace as someone with a lower VO2max. Also, as you get aerobically fitter, for running long distances, it has been observed that VO2max falls. Need to dig out the reference for this. Like anything, there's lots of nuance.

    Some people mentioned race time predictions from VO2max. If you are into running you are better off using recent interval performances to predict race times and measure your fitness. You can use the hyperbolic critical speed model (Similar to FTP). It's only accurate for durations from a minute or so to 20 minutes. Other models can be used to fill in the gaps. This paper explains it [1]

    I'm a big advocate of not getting too caught up in physiology when it comes to running. What really matters is "how fast can you run for race distances" and you can improve that by doing more running at or near race speed. E.g. for 5k, do intervals at 105% 5k race pace and longer runs at 95% 5k race pace. This is the essence of Renato Canova's percentage based training [2] which has been very effective for Kenyan Elite's and also myself!

    I'm currently building out a training platform which uses the omni domain speed model (see below) as the basis for prescribing training paces and workouts. I'm currently using the system for myself to great effect. Managed to get my 5km race time from around 20 minutes to 15 minutes in under 2 years (and im 40).

    [1] "Development and field validation of an omni- domain power-duration model, Michael J. Puchowicz, Jonathan Baker & David C. Clarke"

    [2] https://runningwritings.com/2023/06/canova-marathon-book.htm...

    • hiq 18 hours ago

      Have you compared your lab result with what you'd get with a test like the Cooper test?

      > as you get aerobically fitter, for running long distances, it has been observed that VO2max falls

      I'm surprised by this and can't find good info about it, has this been studied?

      • rojeee 17 hours ago

        Good question. Haven't done a cooper test but from my pace duration curve I'd be looking at a touch over 4km for 12 minutes. The calculator I used online said my VO2max would be 78, which can't be right. I'm one of those athletes with good running economy and a high lactate threshold but comparitvely lower VO2max. I've always been worse than sprinting and at shorter distances than my peers but I find longer distances easier.

        I'm sorry I can't find the paper which discusses VO2max and how it could potentially fall with lots of low aerobic training e.g. aerobic threshold running. The idea of the paper was to show that training to improve physiological markers like VO2max didn't necessarily translate to better race performance and infact sometimes training to improve the marker actually decreased it... One of the things they noticed was that certain marathon runners actually had a fall in VO2max but ended up with faster race times, illustrating that race performance is determined by factors other than VO2max.

        Annoying, if I find it, I'll reply to your comment with the link. It's just one paper though, probably something in it but it's definitely not the consensus view of exercise physiologists.

    • mrfox321 18 hours ago

      20 to 15 is insane.

      Are these low 15s or high 15s? Regardless, that's fantastic progress.

      Do you respond better to intervals or longer aerobic efforts?

      I ask because Ive always wondered if training should be specialized for fast/slow twitch runners.

      Specifically, do you focus on strengths or weaknesses.

      Let me follow you on Strava :p

      • rojeee 18 hours ago

        Apologies, my wife is not keen on me sharing Strava profile on the web as people can basically see where we live (UK countryside and we are the only house in the area!).

        Low 15:00s. I doubt I'll be able to break 15 though as I'm just getting too old now. I used to train seriously when I was a teenager so maybe those adaptations stick with you as you get older.

        It's a good question. I find that the most important thing is running at or close to race pace. I follow Canova's training philosophy quite closely. Definitely recommend reading the runningwritings link I posted above.

        I do between 80km to 100km a week.

        Most of my running is done at a moderate pace. I just do this to get mileage in. Most of it is quite hilly. Looking at about 300-400m elevation for each 10km and runs range from 10km to 20km. Pace is around 4:00/km to 4:20/km.

        If I do a workout, I follow it with a recovery run. Pace around 4:40/km. If a super hard workout then I do two days of recovery runs.

        I never run doubles because I have young kids and don't have the time.

        The most important ingredients are the workouts. I never repeat the same workout. A typical one for 5km training would be: a few km warm up, then 3km @ 97% 5km pace, 2 min moderate, 2km @ 5km pace, 2min moderate, 1km @ 103% 5km pace, then a recovery pace warm down. About 15km in total. That's a hard workout and would be followed with easy running the next day. I would do that workout to improve lactate buffering and improve anearobic capacity.

        For lactate threshold I'd do something like 20x400m at LT pace with walking rest for 3 minmutes inbetween. This is where I might use the hyperbolic model to figure out when all the metabolic byproducts are flushed out so you can basically do the next 400m mostly recovered.

        Other workouts might be aerobic thresohld runs. So marathon pace running for 15km to 30km. These are the long fast runs that canova talks about. They are hard and you need a lot of recovery after. I really find they improve performance quite alot. They are not presecribed in most training plans and I feel they are a key missing ingredient.

        I do a fair bit of hill reps and sprints as well. They are probably best for improving VO2max. Lots of rest inbetween reps, you need to be fully recoved for the next one to get the benefit.

        Lastly, you need to keeo touching on all the various metabolic systems. If you don't use it, you lose it. Keep your training varied. Sprints, short interbvals, long intervals, long fast runs, hill reps, ladders, alternates, with varying levels of recovery and at different speeds. Make sure your training is additive. Don't remove any class of session, just add more different types.

        Do strength/core workouts. Plyometrics. You need to be strong to bash out miles at MP and not get injured.

        I use theragun after any hard workout. Helps recovery loads.

        Eat. Alot. On hard workout/long run days I do about 5000kcal.

        Most importantly, I think, don't listen to any of the 80/20 polarised nonsense, MAF method, or anything like that. One size fits all training regimes don't work very well because everyone is different. They work for beginners because _any_ running will have them improve.

        For more experienced athletes, to run fast you need to practise running fast at the paces you will race at. So doing a training plan which prescribes 80% of easy running as a rule is no good. You only run easy if you need to recover. Every other workout/session needs to target some metabolic system to promote adaptinos which help you run faster. It's the workouts which really make a difference to your race performance.

        • iamacyborg 16 hours ago

          Why are you training to pace rather than a more direct physiological proxy like HR or lactate reading (if you have the kit)?

          • rojeee 15 hours ago

            Simply because I find it gets me much better results. I know that to run a 15 minute 5km I need to be able to run that pace in training. I don't really care what my lactate threshold or VO2max is other than it's just interesting to know. I use a critical speed (pace/duration) model to know what paces are metabolically steady state and which are not. So based upon how I perform in training, I know pretty much what paces should be within the realms of possibility for a maximal effort and I use that to guide my training.

            edit: I'll just add that I do use physiology to guide the training paces. But when you've been training for a while you know that 1) Marathon pace is aerobic threshold pace. 2) Half maraton is lactate threshold pace. 3) 5km is critical speed. 4) 10km is between critical speed and lactate threshold. So whilst I do use physiology to guide trianing paces I don't use a zone system or anything like that. I just design workouts which I know touch on the various systems I need to improve.

    • huhtenberg 18 hours ago

      Do I read it correctly that you went from 4 min/km to 3 min/km?

      That's 20 km/h. As my sibling poster said, this is absolutely insane.

      • rojeee 18 hours ago

        Yeah only for 5km though. I can't run a marathon at that pace!

  • macrolime 18 hours ago

    The VO2Max seems wildly inaccurate. It never activates when I exercise, but sometimes activates when I'm sleeping.

  • xattt 19 hours ago

    One thing I can’t quite figure is if you are not doing a specific exercise to the T is whether your VO2 remains accurate.

    Example: I do interval running, which the Watch just records as a run. If I am not running for part of it (i.e. a 1-minute rest interval), is the Watch actually capturing the right info to calculate my VO2?

    • inductive_magic 18 hours ago

      Wouldn't simply starting a HIIT-workout on the watch solve this?

      • matsemann 18 hours ago

        To me, interval running and HIIT is not the same. I mostly think of HIIT as something done in a gym with a kind of strength/cardio focus, not endurance? But also, even if my run or bike ride was a HIIT, I still would like my normal data / setup for that activity.

    • Raed667 19 hours ago

      i would imagine it depends if you keep the watch recording or paused during the rest part

      • xattt 19 hours ago

        I’m using Intervals Pro, so it’s unlikely that it’s pausing it.

  • iamacyborg 18 hours ago

    Are Apple doing their own thing or are they just licensing Firstbeat’s tech?

    https://www.firstbeat.com/wp-content/uploads/2015/10/white_p...

  • bovermyer 17 hours ago

    I've been using VO2Max to get a rough idea of my cardio health. I'm not an athlete or a runner. I'm 42, and it's sitting at about 31 right now, which Apple tells me is Low.

    So, I guess I just use it as a motivator for going on walks or perhaps starting to jog again.

    • CobaltFire 14 hours ago

      I’m at (exactly) the same point as you: 42 and 31 (though via Garmin not Apple).

      I know my cause and am fixing it though. As recently as 2020 I had a VO2Max of 48, and had lots of issues that resulted in me dropping my fitness regime. I’ve also had some health challenges that impact it that I’m hoping I can recover from soon.

  • e40 19 hours ago

    Isn’t the O2 sensor banned in the USA due to a patent dispute?

    • fellerts 19 hours ago

      SpO2 (blood oxygen saturation) is disputed, yes. VO2Max is a completely different measurement.

  • 082349872349872 18 hours ago

    at what point does Apple start offering a Biometric Identity system?

  • ulfw 18 hours ago

    Mine has been telling me I got very low VO2Max of 26 every day, for years. No matter if I work out or do nothing or go on a 5 mile walk or whatever. Let's just say I take Apple Watch is the gimmick it is. Nice for notifications and setting the timer for cooking though

    • inductive_magic 18 hours ago

      Care to elaborate why you think this reading is so wrong? Vo2max has a significant genetic component, and it doesn't improve unless you actually push your anaerobic threshold, i.e. interval training and long distance running. It doesn't improve by "going on a 5 mile walk or whatever".

    • einburger 11 hours ago

      Mine underestimates my VO2 max to be around 40 which is much lower than what I calculated myself. Turns out the Apple Watch thinks my resting heart rate is much lower than it actually is, explaining the difference.

    • agos 18 hours ago

      do you have reason to believe it should be higher?

  • 18 hours ago
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