Will Whoop Revolutionize Your Training? The Science on HRV 

Have you given Whoop a try? Does your recovery score accurately reflect how you feel on the bike that day?

Thank you Dylan for not doing a whoop commercial. I see them all over the place and happy to see a video on the actual science, not a commercial. You rock man.

As a network engineer I have spent my entire professional life data mining and looking for answers from the pile. What I have learned is that everytime I add a system into the process with the sole purpose of helping me monitor the other system what I am really doing is putting a system in between the me and the system I am being paid to maintain. That means I have to be very careful about what I choose to 'help' me do my job. If I have to spend a lot time troubleshooting the systems there to help me maintain the primary system then it becomes a distraction and counterintuitive to my purpose. I have also learned that these systems do take time to understand and provide a different view into the network that I didn't have before. I don't see this much different. Basically ... is that juice worth the squeeze. Sounds like a very polite no to me.

Backward hat Dylan nailed it in the last bit there. I'm not paying for something that tells me to not play hard, drink hard, and insists I sleep more.

I used the Whoop strap for 4 months. I found the data to be useless. Here is the issue, if you have a coach, unless your coach is writing your workouts based on what your Whoop says daily, it makes no difference if you are rested or not. On top of that, some of my best days were when the Whoop said I was in the red... Until this information can be input into a program like Training Peaks and the metrics turned into something useful, it just doesn't have a place...yet.

I love unpaid, and unbiased review of a product. Listen to backwards hat guy @15:34. Thank you for the video Dylan.

Thanks for your opinion, finally someone who isn't completely sullied by sponsorship (GCN)

I have the Oura ring, similar. It's been interesting. It definitely makes it so you can't lie to yourself about your sleep. I've also noticed a very clear link between my sleep score and my desire to give in to impulsive behaviors like eating poorly and drinking. Just having the data helps it stay in my mind, "you just had a bad night no need to give in.". I'm fairly happy with it.

I am totally flabbergasted. I was positive Backwards Hat Dylan was a Coors light guy. Shocking

Great content as allways! Here's my n=1 on this highly individual topic: I've been tracking my morning HR/HRV(Elite HRV & Polar's orthostatic test) for a few years now, and find it to be pretty useful, however it took a while to figure out what to look for exactly. I never really experienced the "usual" elevating HR, dropping HRV symptoms when fatigued and for a long time i considered my depressed HR and skyrocketing HRV at the end of the 3-4 week training blocks as signs of increasing fittness. I had to find out the hard way, that those were/are the sympthoms of parasympathetic overtraining setting in. Since then i immediatly consider a rest day when encoundering a sudden HR drop and HRV rise at the end of a training block. This type of overtraining is also pretty hard for me to detect by feel since as it starts to set in, during the first few days, i feel the fatigue fades away, my training sessions feel awesome(i mean really awesome) and i sleep like a baby at night. However if i keep going, after 3-4 great days some sickness allways sets in and an optional rest day becomes a mandatory rest week(s). Overall on a daily basis relying on overall feel and how my legs feel during my easy commute ride to work (15-20min) gives me a more precise gauge to adjust my training, than the highly fluctuating HRV, but i'm allways keeping an eye if these parasympathetic sympthoms appear as the accumulated fatigue gets higher. P.S. I'd be intrested to look into the science of sympathetic vs. parasympathetic type of overtraining! ;) Are they occur based on the training done or on personal factors? Which one is harder to recover from? Are the recovery methody any different for the two? etc.

Really great & insightful video, not a Whoop commercial. Top quality. I am a Whoop subscriber since early Jan, so 6months+ now. Pretty similar observations. Bought it to build-up my own intuition, and see how often it matches the 'feel'. Data is sometimes a bit patchy, but 90% cases pretty consistent for the 'extremes'. When HRV score 70. I adjust my planned work-outs based on these ranges. The mid-range is anyone's guess though. Algorithms still need work on. I am a big believer in HRV, but accuracy for stap measurements is maybe not there yet (I also own an ElliteHRV finger tool - this is much more precise for calcs, but takes 3-5mins to measure, and conditions are not always 100% comparable; Whoop still uses some averaging rather than pure RRs - visible if you plot the raw data, via software like KubiosHRV). Strain score is absolute rubbish. 2.5hr gentle endurance ride gets me 19+. Real shame it doesn't allow to enter HR zones (mine are actually quite diff than the standard50/60/70/80/90%). Act HR measures pretty accurate (+/-5bpms), but would not rely on Whoop for HR zone training. Sleep tracking ok'ish, but the strap is not picking-up awake (but in bed) status. Overall, so step in right direction, but not yet 'reading your body' fully as claimed. Loads of algo development needed. Dylan - suggestion for you - what is your view on breathing trainers (like PowerBreathe, Airofit)? Worth doing a video on? I've recently started using Airofit (a Danish company), and seeing some decent progress (HR comming down @ same effort). Likely due to the fact that my breathing technique far from optimal (visible when swimming). Supposedly popular among Scandi endurance athletes, so claim is this could be beneficial at both amateur and elite levels. Views?

very cool to meet you today in Tryon!!

Great video! I didn't buy the Woop because of the monthly subscription since it would be close to $400 a year just to start. I bought the Oura ring instead which it's great, just less than $300 with no subscription at all. HRV it's kind of useless as a day to day metric, but as a weekly and monthly metric there's nothing like it. It literally can tell how your body it's adapting to your training and your overall wellness as well. I found out that the most powerful thing you can do to raise your FTP it's sleeping a lot at the same time everytime.

I'm giving whoop a try and I can say that although it's not a game changer it certainly helps with training and resting. I've improved my recovery habits (resting and nutrition) and I have started to do intervals based on feel and recovery score rather than an arbitrary decision prior to the start of the training month. Great video as always Dylan!

thanks for sharing your specific experience that did not match up with the HRV. Loved the take away at the end.

Since October 2019, WHOOP happy user. simply the best.

I still do the old "check my heart rate in the morning" thing. Consistently in week three of a block I start having trouble sleeping and I have the need to constantly clear my throat, I don't know the physiology behind it, but that is my "recovery week begins now" alarm.

Great video Dylan, I have been using the free Elite HRV app for 5 months now and measure my HRV each morning shortly after getting up. Like you, I’ve found a perfect “10” score doesn’t correlate to me being fully recovered and have struggled to actually link my HRV data with anything I can rely on to be a way to train smarter. I seem to find some correlation between good HRV following good sleep, but again it’s not 100% obvious. One thing the data did show me was that I was sick, when I contracted Covid, HRV data had it flagged two days before symptoms showed.

You knocked it out of the park with this video, Dylan! I don't know anyone else on RU-vid who does as good and thorough a job explaining a concept and the scientific evidence behind it in a way that is relevant and digestible for a general audience. In my opinion, your true talent is making educational videos.

Finally, thank you so much for digging deep into that subject.

I have been using HRV for around 3 years now. Using Elite HRV app, i measure HR 3-4minutes after waking up. Its really useful for me and my coach. I can always plan my FTP tests and important trainings on better days.

I've been using whoop for almost a year now, and I've been finding it awesome. But not because of the day-to-day results. It's the monthly trends that - up until now - really effectively show correlation with performance increases and decreases, as well as better or worse habits (eating late, drinking alcohol, not enough sleep). The big difference it makes for me is making the consequences of those habits visible, which makes it a lot easier to stick to healthy decisions. I'll definitely keep using it!

I'm mostly interested in hyper gainer beast mode raw edition where can get me some???

I was just asking myself today what the science says about HRV and Whoop in particular. Thanks for including those papers, that makes all the difference to me.

I’m with backward hat Dylan!

I think I spend more time watching vids about cycling than I do actually cycling.

I wish it were possible to give this video multiple 👍👍👍

An honest unbiased product review! this channel is a real breath of fresh air 👍 I’m tracking HRV for a few months, using a tickr and EliteHRV for free. It’s like you said sometimes the readings don’t match how I’m feeling, but it does help focus more on recovery.

I use the oura ring. I really like it, I've used it to optimize my sleep enviroment and practices. Made a big difference to my recovery and ability to deal with stress

Thank you for saving me the expensive year subscription for the Whoop, now, where are those super lightweight expensive parts which will give me marginal gains at!?

Hadn’t heard much about it until your video. Now keen to try it

Thank you Dylan for not doing a whoop commercial. I see them all over the place and happy to see a video on the actual science, not a commercial. You rock man. *Copied this from down below - @black water cyclist- but it is exactly what i thought. Are you gonna upload more whoop content? :)

Dylan, there is another issue with HRV in that it is linked to mental state and anxiety. HRV also varies based on stress at work and other mental factors not related to exercise, this can make it a poor measure of recovery unless the user is aware of current stress levels and their effects.

Finally, waited for this since Whoop was there. You're the only guy I trust when it comes to objective analysis.

Great vid! HRV is one of the metrics to consider, but not the main one. Sleep, the lactic acid level in your muscles, blood biomarker profiling, and so on... We are simply not in the era of that type of device that we can totally rely on! At least for an "average" athlete.

There it is

I have been measuring my HRV for about 7 months, but not with Whoop. My takeaways so far are: 1. If you use the camera on your phone, or another non-continuous method, then when and how you take your measurement has a HUGE influence on the result that you get. Experimental measurement errors can be significant. You have to be very disciplined an detail oriented in order to make good consistent measurements. 2. Sleep duration and quality drive HRV at least as much as yesterday's training. Great Video.

With some of the hate Whoop gets and people saying "just train" and "listen to your body" and "get good sleep and you'll be fine" I'd like to add that Whoop is an awesome habit creator and sustainer. I think I speak for thousands of people that love riding bikes but will never get to be in real races that performance by wearing a Whoop will indeed increase because it increases your general awareness of things such as sleep and strain. For top-level athletes such as yourself I can see Whoop not being as useful since you are so in tune with your body but for a sub-300 FTP slugger with a bit of weight to lose and inconsistent training habits it's actually quite a great tool even if it just encourages getting on the bike to begin with when you see a low strain for the day or a great recovery score.

Thanks! I was hoping you'd do this!

To measure HRV you need specific tools used by cardiologist. I've done a small internship in cardiology, doing hearth stress test on a spinning bike. Even with the 6 electrodotes on the hearth there was some errors in the ECG, same deal using a Holter ( a portable ecg used for 24/48h ). These devices placed on your wrist are so inaccurate.

I'm 49 and back into competitive cycling after a 10 year break with no real endurance exercise at all. 10 years ago, I had no data except heart rate so, I've gone 180 this time and I have all the data. Including Whoop while its not perfect, it does help me many days, and it reminds me how right it is when I refuse to believe or, train through poor recovery scores. When I wake up in the morning yes, I can feel big differences in my body's recovery (completely rested vs. smashed) but it's hard to feel subtle variance. I feel largely the same every day while training. On those more subtle days, Whoop tells me some days my recovery is green, most are yellow and some are red. While I can make myself do any workout I have prescribed regardless of what whoop says, I notice that I definitely recover better from a workout on those green days and I struggle to recover on the red days even though I may have felt very similar in the morning on those green and red days. For me, whoop is helpful, but it is expensive. Strain score is useless.

Thanks for the post. Noticed my HR has been higher than “normal” lately and have been considering Whoop or Oura and it’s great to have a breakdown of the science and a trusted opinion. Thanks for your honest reviews!

Been waiting for you to cover this!

I thought Backwards-Hat-Dylan would ultimately be the "Yes" column because it gives him a great excuse for getting dropped LOL

Great video - I tried whoop for 3 weeks. Im a data driven masters athlete (wannabe) and I really wanted it to work. Unfortunately the heart rate monitoring device was simply not reliable. I’d get on my bike and start warming up and my Garmin chest strap would indicate my hr was 85bpm and whoop would say it was 155bpm! There were times during the day when I’d be doing something pretty low key like sorting through papers and whoop would detect a high effort workout. The optical sensors have been shown to be less accurate than the electrical chest monitors. I conversed with whoop support - they were great - and I tried multiple wrist positions and strap tightness but simply could not get consistent high quality data. In the end with huge regret I sent it back. I found the app itself to be excellent though the strain gauge was confusing as you reported. DC Rainmaker also has an excellent review where he encountered similar problems to me.Perhaps it’s a physiology thing that is specific to me - my skin or how much the muscles in my arm move around!!! I will wait to see what further iterations of the device use for heart rate monitoring - perhaps more sensors or better sensors. If these improve the accuracy then I may give it another shot.

Back in 2008-2009 Polar had a watch that was marketed for triathletes that had a protocol to be completed in the morning after waking up. It measured waking resting heart rate then had you sit up and relax, to get your heart rate to spike and recover; then stand and relax. HRV was measured, reported and used for determining recovery in their training software. It is interesting to me that something that has been available to athletes for well over a decade, is just now coming into the limelight, but this time requires a subscription to get the data. I think I'd rather just see if I can dig up the old polar software and equipment.

Thanks a lot for taking time to do research and test device over a couple of months. Myself, I've considered HRV to be meaningful and almost jumped on the bandwagon, but thanks to you work - I won't! I think I'm already happy with accuracy of reading my body's signals and don't need another gimmick. Cheers!

I just finished filling out a return form to send mine back.

Glad someone finally did a scientific review of whoop.

I'm using Whoop and after the first couple weeks of using it I realize that it's better as a sleep habit forming device, rather than a way to dictate how I train. So far I've been getting more sleep but not necessarily better sleep, unless I go to bed really early. I like that it tracks HRV and I also use HRV4Training + Apple Watch to compare the 2. Same thing, good as a habit forming thing, but I still train then review the data later.

2:45hrs with 281 NP you're a beast. Great video too. Thanks for sharing

You should have really researched whoop alternatives for this review. You can monitor HRV with as little as your phone camera and a free HRV4TRAINING app. What I use is the Oura ring which is very similar to the whoop strap but you can also output the results to HRV4TRAINING. Apple Watch 3 & up can also output HRV data to HRV4TRAINING. None of these options have a subscription fee. Unfortunately despite high hopes I haven’t found tracking HRV super useful. It seems to go up and down in cycles and is not very decipherable when it comes to training adaptations. I’m hoping that the science improves allowing more concrete analysis.

Good point to make Dylan that, if nothing else, it makes you think about your habits and encourages you to make healthier choices. I have experienced just such an effect using a freeby Garmin Vivosport - a realisation that I am consistently getting 6 hours or less sleep has meant I've at least nudged that to around 7 hours, for example. Sleep being so important to recovery has meant just doing something this simple has got rid of recovery niggles/injuries when I am training hard. Seeing those numbers has made me stop and think and while getting a golden 8 hours every night and plenty of deep sleep is a way off at least I've taken some steps in the right direction as a result.

Awesome post and solid analysis. Thanks! Whoop sponsored content has been driving me mad. I think backwards hat Dylan summarised it best!

I prefer a Polar Vantage watch. It does a great job checking your sleep quality and also measures breathing patterns during sleep and also HRV. Additionally you can do an Orthostatic test with it which is the gold standard and most scientific way to judge your heart rate variability recovery together with resting heart rate! Your watch saves all the results in Polar flow and determines an average to determine when you are off your fintess. But you dont have to rely on that. You can intepret the patterns yourself. How RHR and HRV behave in a fatigued state. There are clear patterns that can even show what kind of fatigue you have. The patterns look different for too much volume or too much HIIT work! And you buy it only once instead of subscribing. A great concept. Polar has done a great job. WHOOP might be easy for Dummies who want three colors and can live with the fact that they dont know squat about how Whoop determines what it determines. If you understand the subject, a Polar vantage watch is a far better and more accurate tool and gives you a lot more insight in the details. And the orthostatic test is gold!

Reverse cap Dylan was brilliant again. Thank you for the review.

Been looking forward to this one, even though I am dissapointed in your findings I am glad I now have the correct information. Thank you for making it clean and bite size.

I don't use Whoop, but I do have a Garmin that does HRV. I appreciate all the research that goes into your videos. I especially liked this one because of your unbiased opinion on Whoop. I also liked the information on HRV.

Dylan, keep the science based info coming. Thanks. And Busch Light doesn’t count as beer.

Hey Dylan, thank you so much for this video. I asked you about this months ago and it was so worth the wait. I use hrv to monitor my moments of functional overreaching aka the moment you get optimal gains for your training. In my opinion you could have emphasized this more knowing that being in the red or yellow does not mean you cannot perform. The boaty guys prooved that. What it does mean is that I am not likely to get training gains (or not as much) from overeaching. This is also the conclusion of the study you mentioned. As I read the comments loads of people are missing that point. For me that is the core essential of hrv. Be it whoop or any other device. Again. Thank you so much. Love your channel. Fan from day 1

I'm with "reversed cap Dylan" on this one :-)

Cool - had been wondering about this. Thank you for the honest and fair video.

thank you Dylan !!!

I’ve read through the majority of the comments and while I think some criticism is valid, most are missing the point of WHOOP. It’s not the hardware that’s the selling feature, it’s the way the data is displayed that you’re paying for. And as an Apple Watch owner, I can tell you that WHOOP does an excellent job of displaying and explaining what the data it collects means, or *could* mean... in the end, these are just tools to help you, not a strict set of rules to live by.

Classic episode, I’ve been on the fence about whoop for a while, I’m not investing, cheers Dylan.

Awesome review. Thanks Dylan.

Thanks for clearing this out, I mostly use strava and garmin connect to compare intensity between weeks and listen to my body. 9-10hours of sleep after a big endurance ride or monster intervals. I'm good with 4-5h sleep after a recovery or break day. Your content is awesome!

I have had a whoop strap for nearly a year and I have come to find the Recovery metric really useful to help decide on whether to stick to my training schedule or replan. I am an older endurance athlete with a tendency to over train and who doesn’t have a coach. Consequently getting the data is very helpful - though I know from experience that it is not going to be 100% accurate.

I've tried the Elite HRV and WatsonBlue apps this year and stuck with Elite HRV because it works with my Wahoo Tickr chest strap. Generally my "feels like" and HRV readings match. There have been a few occasions when I rode better than the HRV results indicated, and days when HRV said I was good to go but could barely move my legs in circles. When I factored in every potential complication, the HRV app still turned out to be accurate more often than not. For example, if my legs, core and arms were dead from weights, squats, push ups, etc., a perfect HRV score wouldn't translate to a good day on the bike. Ditto side effects from diet and medication. If I'm feeling palpitations and skipped heartbeats from too much coffee or my allergy and asthma meds, my "feels like" day on the bike and HRV scores probably won't mesh. I've had a few good rides even when the HRV app said I should take a rest. But most of the time when I ignore the HRV results indicating I should rest, and ignore that advice... I'm probably gonna have a bad day and need a day or two recovery. But those are exceptions. Usually the HRV app and how I feel mesh. And I've done the blind testing too, waiting until after a ride or workout to check my score. So it doesn't seem to be heavily influenced by confirmation bias.

Great review, thanks. Last thing I need is another monthly subscription. Training Peaks, TrainerRoad, Zwift, Strava, Spotify, sorry but this thing missed the boat.

Thank you for your interesting content. Watching nearly all your vids. Great.

Great video Dylan. I've been wondering about whoop myself. I've also been wondering about my HR range and what studies are out there. Personally I have a typical resting HR of 52 and not long ago I recorded 44. Going hard on the bike I struggle to reach 170bpm. Im positive it's been higher, but I guess it might be age (37), my fitness is higher now and I weigh less. It might not be that interesting but I was hoping you know something out are able to so something on that subject. Eagerly awaiting your next video.

I was going to write you and ask you to cover this, so thank you very much. I've been using the Autosleep app on my Apple Watch, which gives me the majority of the data that the Whoop does and I've loved digging into it. However, I just didn't know how useful it was. It's great to see the research. My "real feel" vs. HRV outcomes match up a lot like yours did. I think it's pretty close but not always. Please keep us updated on your opinion on this and if anything changes.

Great video, very informative!

thanks for your great content!

Dylan - love your videos. There’s a really important caveat in the research that you’re comparing here (and perhaps you controlled for it) - HRV measurement qualities vary dramatically. SO, if the study in question used overnight HRV measurement from a lab quality electrocardiograph then the data quality is likely higher than a cheapo wearable. During the earliest stages of the COVID pandemic I got in a conversation with a super knowledgeable engineer, hoping that we could use HRV and other wearable metrics to track and monitor folks on a large scale - he said ‘no’ the data that most wearables produce simply isn’t good enough or consistent enough to make anything generalizable. So, unfortunately, while HRV MAY have some utility, my hypothesis is that the current level of devices aren’t ready for prime time. For example, the Apple Watch can do high quality heart scans, BUT that’s not necessarily what they’re doing the 4x per day when it measures HRV. I really want this to work but don’t think it does...

Thanks for the detailed review - lots of vague info about HRV out there. Using Whoop now for about two years, on structured/coached training/racing throughout. Takeaways: 1) sleep is single biggest factor in terms of recovery/adaptation, but sometimes you go green on less than recommended sleep for full recovery because, dunno, slept better? 2) Life stress has a huge negative impact on HRV, 3) Indeed, alcohol has big negative impact - I've essentially eliminated beer (!), and large sugar load can also have a negative impact, 4) backing out to the week+ view is indeed the best way to evaluate overall trends and 5). I want to stop paying the way-too-high fee for Whoop to take all my data (!), but it's possible to get somewhat addicted to seeing the numbers - not sure if that's good or bad.

On a serious note. Photodiode sensors tend to be problematic unless you have the complexity of an elf. I found scores all over the place with various iterations of garmin/fitbit wrist wearables for pulse. One solution that works fine is a good old chest strap and using elite hrv or a similar website to calculate and track HRV scores.

Thanks for putting this together, Dylan. Good stuff, as always. Using Golden Cheetah (or Training Peaks) to track workload, rest and fitness seems to be a better way to go about it. Last week I was procrastinating on my interval sessions only to realize I needed to be better rested. Whoop won't get my $ this time.

Awesome. I 100% recommend your videos 👍

Subject suggestion: Carb cycling for endurance athletes.

Been watching your channel for a while now and didn't know until you showed the map w/ Hendersonville that you're in the area. I love Transylvania County road riding!

Enjoy your take on training. I use a device called SpiroTiger (from Switzerland) which exercises the lungs and reduces my HR by up to 30 BPM. The intake of oxygen and the training of lungs is always overlooked in training, the more oxygen you have the better your performance/recovery. Check it out.

Great video this week Dylan. I was thinking the same when I looked into it few months ago and was thinking it might be worth it at around $5 per month. Now it’s onto a TR review? 😂

You can get all the benefit of measuring HRV with a free app and one-time purchase of a Bluetooth capable HR strap. Measure it first thing in the morning, adjust training as necessary.

I’ve tried 5 different HRV trackers, including Whoop, over the past two years. What works the best? My mood. If I feel positive and excited to train, it almost always means I’m ready to go. If I have hesitation or a nagging feeling that I’m doing to much, it probably means I am. As Dylan mentioned, the trackers did help drive home the importance of good sleep hygiene. But now that I have a better appreciation for sleep, I’ve ditched the trackers and went back to focusing on my mental/emotional state.

It's logarithmic. Hard, but doable, to get to 20+ but astonishingly hard (impossible?) to get to 21. Think of an exponential curve and consider the difference between 20 and 21 if 21 is the furthest extent of the graph. Love your stuff Dylan and thanks.

The range in HRV is wild. I’ve seen as low as 11ms (after two beers after a six hour ride) and as high as 200ms when fresh.

thank you, i will stick with my HRM and Powermeter :) i'm already paying monthly on zwift lol

Great video, for the first time I'm following backwards hat Dylan's advice on this one, I looked into the whoop and ditched the idea - too much $ for the data you get.

Super helpful. Been wondering whether it's worth it and now well informed

Wow! This is the first time that BHD fully nailed the analysis....

A broken clock is correct twice a day. Great video

backwards hat dylan is always scheming... and that's why we keep him around

Thanks, that was exactly the video I needed

As for your idea of using it to guide training design you would first need to do a baseline 12 lead ECG and a prolonged cardiac monitor so you could exclude anyone with AF, Wenckebach, frequent ectopics etc. It could only ever apply to people with completely normal electrics to begin with. Then I get them to breath at a fixed rate maximum breaths whilst supine. Even then I’d be skeptical.

Great video. Thank you!

Hey Dylan thanks a lot for that video although it came a little bit too late for me. I was using my strap for a week. I got it because I wanted some kind of metric to tell me when to train and when to rest and also to see how good I sleep and how much recovery I need. My experience was very strange. After the first few days I had a rhr of 38 and an hrv of 90. recovery was 61%. I thought well, this doesnt look that good, but my legs feel phenomenal and an intervall session was planned. So I went out and smashed it and had the best bike ride of my life. Even rode an hour in the evening as a second training that day. Next morning I felt pretty sore and fucked, but my hrv was at 140, so much higher. Recovery was at 91%I thought like what the f how is this possible. This cant be right. Rhr was elevated by 4 beats so I thought my body isnt recovered, so why is that device showing me it is? I did a long endurance ride that day. After that, my recovery went down again. Along with my resting heart rate. So the next day it was something like 68%. I did a 6 hour ride that day with lots of climbing that day. Biggest ride of this year. Still felt pretty fresh afterwards but it was a big load for the body obviously. But the next day my hrv was crazy high and again I thought what the f. Took the day off because legs were fucked. Next day hrv even got up further (152). Unfortunately I thought well ok lets try if this has anything to say about my real fitness. Because I felt ok, though legs were not at their best. Did an intervall session and felt terrible afterwards. Legs were completely toasted, I had to ride almost all the intervalls standing up and couldnt ride endurance zone afterwards. Really got into overtraining and ate my entire fridge that day because I felt terrible. Now I wonder how I could have been so stupid not to listen to my body and just go out because a device is telling me I am at 91%. My message is this: Hrv can increase for some people after hard training. Recovery can increase after hard training. For me: the best days on the bine were when i had a lower hrv. And for me I found that looking at my resting heart rate was a lot more useful. Lower rhr= better performance on the high end. I find it strange that whoop doesnt take rhr into consideration that much. I felt like it is completely left out of the formula they use. Pretty strange. So thats a big issue for me and I hope they can fix this. Anyway guys, do as dylan says: listen to your body and listen to your legs. Thats a lot more accurate than a strap on your wrist. Trust me on this one. And especially: dont force anything. If you dont feel like it, although you have a high recovery, take the day off or do a little endurance work.

Garmin watches use HRV for their recovery monitoring too (And it does heart rate, daily steps and sleep, as well as telling the time and a load of other options depending on the model you buy). Given you can get one of them for about $200 and there's no subscription fee for the app, and it'll log your rides with built in GPS too, Whoop looks like really terrible value - at $18 a month in less than a year you'll have paid enough in subscriptions to buy a more versatile Garmin watch that'll still be going and does a lot more with no continuous subscription fees.

So HRV as an indicator of fatigue/recovery might be better measured by a sleep monitor worn everyday and analyzed weekly? I hope to see this feature in the next iteration of smart watches I'd like to wear. Since they already measure HR, hope it won't be too hard to add HRV measurement function? Great video as usual, Dylan. Thanks. :)