I'm super interested in data behind myself and my body but never really found existing wearables that interesting – even Apple Watch (I have a Series 3) which I like how it looks but I found it annoying that I need to tell it when I'm working out I ordered Whoop after looking at it a few times over a couple of months and their model of the band being free (or cheap?) but then you pay a subscription to use the app etc was interesting but £30/month is overly expensive I think. I also looked at the Oura ring which a couple of friends have – and love – but I don't like wearing rings so that was out of the question – I really liked how Whoop's 4.0 band was minimal, no screen and very flat to my wrist – and the app looked great too. One thing I really like about it is the charging is done through a little black "puck" thing which slides on top of the band. I charge the puck daily via USB-C and then when the band itself gets low on charge (lasts 3-4 days on a full charge) I just slide the puck on top of it and continue my day until it's charged so you really never have to take it off. As far as I know it's also waterproof but I don't like the feel of the fabric band being wet so I just take it off when I shower. The app is good and collects a tonne of data including calories burned, heart rate variability, blood oxygen level, respiratory rate and more and being able to capture those without any manual input is really nice. It also lets you know if any of the things I mentioned get outside your "normal" zone which can be an indicator of injury or illness and being able to get a heads up if you might be getting sick ahead of time is really interesting and one of the main reasons i got it. You can also generate a PDF of your insights which is interesting and I haven't seen other solutions offer that (though I could be wrong)
While the band itself is really well made and good quality, and I am really happy using it, sometimes it makes mistakes and I'm not sure if that's to do with the band or the app. Sometimes it will show my heart rate as being 20bpm for example which is in the red zone for being unusual – but then when I tap on it it will say it's actually 120bpm which is fine because I'm doing exercise. Which is confusing. It also did take a long time to ship – about 4 months but I believe that was due to high demand so I didn't mind that much. The App is also a bit confusing – I don't particularly like using it as there are a lot of sections and it can be hard to remember which bits of data are in which sections or how to browse to find what you need – but the design of it in general is nice.