I’m using Whoop since July and HRV4T since 2018… they are pretty aligh in my experience on the HRV estimation.
But I found that sometimes whoop overestimates my heart rate when I’m resting, there are a lot of spikes in the graph.
If you need a good and cheap software to calculate HRV, HRV4T is really good.
Whoop is a more complete app, with 24h and sleep monitoring.
How are you finding the sleep tracking to compare? At this point that would be the only metric I’d continue with Whoop for, as I’ve read somewhere (I don’t recall how credible) that the Whoop sleep tracking is considered superior to competitors.
This is also my biggest concern.
After using Whoop for about seven months, I think I’ve learned about as much as I can learn (that is useful for me) on the HRV front (how my body reacts to various things, etc.).
I also have my doubts about the usefulness of any single day’s HRV measurement. I definitely had days when the measurement made no sense and didn’t reflect how I felt. I think the way Whoop measures HRV may not be perfect for any given day. That said, for me, it was about figuring out trends based on various inputs (different workouts, alcohol consumption, sleep, etc.). And it was great for that. The results actually changed some of my behaviors.
That said, I’m still often surprised by the sleep results, and I want to continue to monitor my sleep performance. I’m trying to figure out if a Garmin Fenix 6 can do that (and a lot more).
Here is a link to a study Garmin did on sleep tracking accuracy. Given who funded it, I guess we should take it with a grain of salt. https://www.garmin.com/en-US/blog/health/garmin-health-announces-sleep-study-results/
I wish Whoop would release the results of a similar study. Or even better, it would be great if an independent company did a comparison study of several sleep trackers, including these two.
Will
Garmin sleep tracking is not great after you have tried the Whoop. I find Garmin to be inaccurate on my time to bed (IE if I lay down to read it thinks I am asleep). It is also inaccurate in awake time (It basically never detects when I am awake in the middle of the night like the Whoop did). It also doesn’t seem as accurate at predicting deep sleep (or rather, usually picks up less than the Whoop would usually predict).
However, after using the Whoop for years, I feel like I already have a good handle on my sleep patterns and corresponding behaviors. I treat the Garmin data as it is, not completely accurate, but it gives me a general idea.
This was my experience with a Vivosmart 4 when it first launched, I had wondered if the new watches had better results.
Anyone know if you can continue to use whoop as a HR monitor after your subscription has expired?
With the Whoop 3.0 you have to turn the broadcast heart rate feature on in the app, but once turned on it will stay on as far as I’m aware. So I would think that it will keep working even if a subscription lapsed.
Once question would be whether the heart rate broadcast has to be re-enabled if the Whoop goes completely dead, or if it remembers being on once recharged. I haven’t tested this I tend to keep if charged.
Umm, Whoop does have a study about how well it performs as a sleep monitoring device, it was done by the University of Arizona, so maybe it’s ok. Can’t find the actual results though…
Digging around for 5 minutes on researchgate, you can find several published articles that study sleep using Whoop to get data, so I think that speaks to some level of comfort with the accuracy of the device.
The URL you linked says they’re behind schedule and still recruiting for the study.
I somehow doubt they are almost 2 years behind, kind of a little suspicion that the results aren’t available yet, tbh. That said, there are lots of other studies that use Whoop as a device…
There is one study that they use on their website as validation for the Resting heart rate, HRV and time in certain sleep zone, perhaps that helps:
I haven’t read it myself to be honest.
I found this very helpful - thanks 
If anyone’s curious my “Weekly Performance Assesment” from the WHOOP app this week reports my “Training State: Optimal” and that I’ve “maintained an optimal balance between Strain and Recovery”.
Which is great, given that I’ve been struggling with some mindset issues and wasn’t on the bike or under a barbell at all last week. So I’m still training, I guess? 
Mine said “Sustaining”
“You sustained an optimal balance between Strain and Recovery while also overreaching some days. This will help build fitness over time when matched with healthy Sleep.”
I was in the third week of a three week block with some tough threshold and endurance work and a little VO2 max work mixed in.
been using the whoop for over a month. It really does validate my feelings. when im feeling crap, i can see its because my HRV is high and my recovery is low, I really notice it on the trainer. When my recovery is high? Im Pinging. its great. I’m now competitive about my sleep and can see when i need a recovery week and a rest. I like it a lot. well worth the money.
Has anyone managed to “free” their sleep data from Whoop or TrainingPeaks? I’d love to get it into Apple Health or somewhere it can be accessed by other apps. The sandboxing of the Whoop data is getting obnoxious.
also, are you trying to get TSS, or are you trying to get faster ?
They just sent out an email blast with a link to an abstract to an as-of-yet abstract-only paper. I’m curious to see the full text
Thanks for sharing. Any idea what this means? “ Dr. Sairam Parthasarathy, medical director for the Center for Sleep Disorders at The University of Arizona’s University Medical Center Tucson, and his team, who conducted the validation study published last week found that WHOOP accurately detects sleep duration with a precision of 17.8 minutes.“
Guessing it means they were +/- 17.8 min on actual (i.e., recorded by other means) vs Whoop derived sleep duration.