amazing data when it stays connected to polar h10 but most of the time it doesn't
Developer response
Thanks for your feedback David!We’re glad to hear that you appreciate the data quality,but we’re sorry about the issues.Making sure the sensor is updated and not connected to other apps(eg Polar Flow;Smartphone Bluetooth).If you like, please reach out to us [email protected] - we’d be happy to take a closer look and help you get a stable connection.
Most of the reviews below are rubbish, here is what you need to know: - I have not done any scientific experiment, but the app seems very accurate, more than any other ring/watch out there; - You start receiving useful feedback after the app collects enough data. It took me 55 nights before I started seeing feedback. Sleep2 folks: you said you are working on major updates, including polar loop integration (OMG, exactly the feedback I wanted to send you!)...what else :)? Keep up the great work!
Developer response
Thank you for the great review and your trust in sleep²,Tommaso!We’re happy that you appreciate the app’s precision&the insights into your sleep provide real value.We are continuously working on new features/improvements and we're glad to have you with us on this journey:)Thanks for being part of the sleep²community and for sharing your experience
scam
Developer response
Hello Martin! We’re sorry to hear that this is your impression, since that’s definitely not our intention. If something didn’t work as expected or caused frustration, we’d really appreciate hearing more details so we can help and improve. Please feel free to contact us at [email protected] - we’re happy to look into your case.
will connect at the beginning of the night, but about 60% of the time it will not connect in the morning to assess your sleep data. I try everything it recommends in the prible solving section and that will only work about a third of the time.
Developer response
Hi Brandon!We’re sorry to hear that the connection often fails in the morning!In some cases,this behavior can be related to certain Polar firmware versions or to the simultaneous use of the Polar Flow app,which may block the connection. Please contact us at [email protected] we can review your case individually and help resolve the issue quickly.
Could not connect to my H10 sensor no matter what I tried. The instructions on their FAQ page are not helpful at all. Also, the app expects me to not install a firmware update for the sensor which has been released over 2 months ago... and they still have not made their product work with it. Overall very unprofessional experience, too bad I really wanted to test their algorithm.
Developer response
Hi Zlatin,we’re very sorry for the inconvenience!Issues are related to a Polar firmware update, which can cause connection problems.The root cause lies within Polar and will need to be resolved by them directly.Please contact us at [email protected],we can provide a suitable workaround and want to ensure you can use sleep² reliably
Using it with Polar Verity sensor. Bought a year subscription because of supposed algorithm accuracy and future potential. But at this point I am starting to get a bit disappointed. The app could use a lot of improvements but it seems development is either really slow or halted. Not sure if I will renew. Sleep values also strangely seems to be 100% identical on many nights, which I find hard to believe..
Developer response
Thank you for your honest feedback!Your input is highly valuable in shaping improvements and we’re sorry to hear that you’re feeling disappointed!Please contact us at [email protected],we'd love to clarify things with you together! Btw:We’re working on major updates (Polar Loop integration,algorithm upgrade, AI-driven sleep&factor analysis coach) :)
After a month of trying it out, I still can't grasp the purpose of this app and am very frustrated that I spent so much time entering data into this. Implementing a simple model or using AI to directly correlate my potential influencing factors with my sleep data can't be that hard. W/o these insights, I merely see the data from my tracker in another view and get some nice videos with tips or the usual relaxation techniques. I'm grateful that this was sponsored and I didn't pay for it myself.
Developer response
Thanks Caro!The best results come from combining sleep statistics with the intensive sleep training(especially when using a Polar sensor, which provides very valuable insights into sleep).A major update is coming soon incl improved sleep coach&sleep factor analysis,which will make the connections between the factors you enter and your sleep clearer
Hello, is there an English version of the app? I'd love to test it's sleep tracking with the H10. ..... editing this after testing as the app is offered now, it is completely worthless. don't waste a night of wearing the H20 and battery, you will literally get nothing but sleep duration unless you sub. as hyped this app is, the monetizing aspect is atrocious also not worth giving the app your data in the profile that you need to complete cheers
Developer response
Thanks for your interest in Nukkuaa! We are currently working on the translation and want to publish it soon. We're looking foward to welcome you to Nukkuaa as soon as the English version is available. Subscribe to our newsletter to receive the latest information about that:)
can't connect with polar h10 at the end of the night EDIT: App owners contacted me and helped me make this app work. If you're using h10 polar strap, download the latest software update for it in Polar Beat app. Then before you go to sleep, unpair your h10 device, close all apps except h10, click sleep now and then pair your device when prompted. Overall this app gives useful insight and helps with sleep regularity. However, I don't like the idea of manually clicking "sleep now" on my phone.
Developer response
We’re very sorry Szymon!The issues you describe are currently related to a recent Polar firmware update.Please contact [email protected],so we can check your case individually and provide a suitable solution!We’ll take care of this and do our best to solve the issue:) If your experience improves, we’d really appreciate it if you updated your review.
The app is good. however the free version doesn't allow to export your actual sleep data. It will not upload the sleep data the google health connect. I understand that the developer wants to earn money with sleep coaching; the sleep tracking and data forwarding should be free of charge. Remember that this algorithm was developed with public funding.
Developer response
Thanks for the feedback Urs! sleep data can always be exported to Google Health and you can request your data as a CSV file from us.The algorithm was developed within the context of a project at the University, but further development (e.g. app, continuous improvements) takes place outside of that project and was/is not funded.
absolute rip-off. The app constantly fails to fetch the data at the end of the night, meaning another night wearing that sensor for nothing.
Developer response
We’re very sorry Charlie, this is understandably frustrating! The issues you describe are currently related to a recent Polar firmware updates(VS:3.0.15/H10:4.1.10).Please contact us at [email protected], so we can check your case individually and provide a suitable solution!We’ll take care of this promptly and do our best to improve your experience
no "more" menu. no automatic sleep tracking menu to export raw data. i just got a subscription and found out that yhe "more" menu as mentioned in faqs doesn't exist. i am using android
Developer response
Thanks Wiley!The wording have changed slightly after an update,you’ll now find everything under “Profile”. There you can access GoogleHealth to import/export your data.We’re sorry for the confusion caused by the outdated FAQ and will update it accordingly.If this clarification improves your experience,we’d be happy if you reconsider your rating
Pretty Good in accuracy and short sleeptips- nettes design.
Developer response
Hello Lukas, thank you so much for your positive feedback! We’re glad to hear that you appreciate the accuracy of our sleep analysis and enjoy the short sleep tips as well as the app design. We hope sleep² continues to support you in better understanding and improving your sleep :)
I'm a little overwhelmed by the layout. Videos don't play at all so I can't finish the sleep training. But it works even without a tracking device which I really appreciate even if my manual logs are more rough estimates
Developer response
Hi Jessica,thanks for the positive rating despite the issues you’ve encountered!You’re right, sleep² can be used entirely without a tracking device:)But we’re sorry that the videos aren’t playing - that definitely shouldn’t happen. Please reach out to us at [email protected] so we can look into this directly and restore full functionality for you
I've spent more than 3 hours trying to connect this app to verity sense. No success
Developer response
So sorry to hear about the connection issues!Often the Verity Sense is still assigned to another app or running in a training mode.Please remove other connections,restart phone, click sensor once to activate and pair it only via sleep². If it still doesn’t work,email us at [email protected]–we usually resolve this very quickly and are happy to help
Sleep2 is the first app where my sleep data truly matches how I feel in the morning. I still track my sleep with both a sport watch and Sleep2 using a Polar HR sensor, and when results differ, Sleep2 is always closer to my feeling. The detailed analysis, proven accuracy, and clear insights let me see how habits like alcohol affect my sleep. It’s not abstract theory, it’s my nights, my habits, and my metrics showing me the consequences. That makes the advice far more powerful and actionable.
Developer response
Thank you for your outstanding review, Damjan:)We’re delighted that sleep² reflects your actual sleep experience so accurately and that our HR-based analysis with the Polar sensor provides insights you can truly relate to.That's what we aim for-translating scientifically validated data into personally meaningful feedback that helps improve sleep:)
I'm impressed with the program's design—easy to read, visually comfortable, and highly accurate. I've used it for a week with Polar Verity Sense, and it's excellent at tracking sleep. I'm confident using it for my mother with dementia to monitor sleep for medication management. The staff is also very responsive, helpful, and provides clear information. I truly appreciate it and I’m very happy to have had such a wonderful service experience with the staff team.
Developer response
Thank you sincerely for your review:)We’re very pleased that sleep² provides clear and reliable insights into your sleep using the Polar Verity Sense. It’s wonderful to know that our solution also helps you support your mother’s sleep. We greatly appreciate your recognition of our team’s responsiveness and commitment to clarity and care. Thank YOU!
i am a paid subscriber but unable to track my sleep with the polar verity sense. after tapping on wake up it says incorrect sensor data and does not show me any readings. please help
Developer response
Hello Joydip Sen! We’re really sorry to hear about your problems - that definitely shouldn’t happen and we’d love to help you personally! Please write to us at [email protected] - so we can look into your case in detail and find a solution together. Hopefully, once everything is running smoothly, you might consider updating your rating? :)
The app is great. It's accurate, has a clean UI, and doesn't feel bloaty like others. What really impressed me was the support I received from Theresa. My new phone and the Polar H10 were giving me connection issues with the app. Theresa emailed me back and forth constantly over a few weeks to get it sorted. It ended up being a known issue on Polar's end, and the Sleep2 team took it upon themselves to compensate me by sending me a complimentary Polar Verity Sense to use instead. Thanks Theresa!
Developer response
Thank you so much for your amazing review, Nathan! We’re truly happy to hear that you’ve had such a positive experience with both - the app and our support! We appreciate your patience and are pleased we could offer a good solution. We're happy that you are part of the sleep² community:)
well organized app. reviewed as having very accurate sleep data. simple process. however, app is a little busy on first use. support is very good if you are on a subscription. I use it with a Polar Verity Sense
Developer response
Thank you Andrew for your great feedback:) We're happy to hear that you appreciate the structure of the app and the sleep data accuracy—especially in combination with the Polar Verity Sense. Since we’re continuously working to make the onboarding process even more user-friendly, your comment regarding the first-use experience is noted.
I’d really appreciate an API connection for fetching data, or at least a simple export option to CSV. Other than that, I really like the app.
Developer response
Thank you for your feedback:)we’re glad to hear you like the app overall! A better export option for users would be very helpful and we're happy to share that an expanded export feature is already in development.In the meantime, feel free to reach out to us at [email protected] – we’re happy to provide you with your data manually.
very expensive subscription
Developer response
Thank you for your feedback, Mahmoud–we understand that the subscription may feel like a significant investment.Please know that it helps us continuously improve the app, develop new features, support ongoing research and ensure accurate analysis.If you're just getting started, feel free to try the free basic version first to get a feel for sleep²
Only use it as I do not have an Apple Watch and I trust the Quantified Scientist review of sleep stage accuracy. I am a paying user. Very little value. Asks for input on behaviors but no insights on the impact of those behavior inputs so that is a waste of time - zero. 2nd - faulty battery readings. It thinks the Polar battery is low and refuses to connect. Last night the battery was allegedly 20% and tonight it said battery too low and won't run. so somehow it lost 20% in one night??
Developer response
Thanks for your review! Due to the limited space here, it’s hard to respond in detail, but both (behavior insights via factor analysis and battery handling) are being improved. We’d really appreciate it if you'll email us at [email protected] so we can take a closer look and support you properly!
Pretty good already, looking forward to updates that provide insights on correlation of lifestyle factors and sleep for the 5th star Edit: very happy to see that you can now add and track custom factors. Now the only thing missing is the correlation analysis feature. Hope it will be released soon cause this is what actually would make this app useful for somebody who already knows sleep hygiene but wants to see which factors are important for their individual case
Developer response
Thank you for the great 4-star review! We're glad you're enjoying the app and happy to have you in the Sleep² community :) We’re also really looking forward to the upcoming update on the factor analysis (among other things) — because it will give a good insight if and how certain factors influence specific aspects of your sleep.
I have constant problems with device connection.
Developer response
Thanks for the review Iryna! We're very sorry to hear that you’re having trouble - Often the issue comes from the sensor being connected to another app, which blocks sleep² from accessing it. Feel free to write us at [email protected] – we’d love to help and get things running smoothly for you!
basic version is nearly useless with an h10 strap. paid version is too expensive.
Developer response
Thanks for your feedback! The free version gives a first impression of sleep² and provides the most important core values, while full sleep-stage analysis is unlocked in the premium version. Our pricing helps fund ongoing scientific studies and app improvements, but we understand that it may not be right for everyone!
decent price. very accurate. good format and comfortable to use
Developer response
Thank you so much for the great review, Jed! We're really happy to hear that you appreciate the accuracy, pricing, and overall usability of Sleep². It means a lot to us – thanks for being part of the sleep² community :)
Tracking seems to be quite accurate, but how would one know? The ml model seems to miss some of my awakenings. In any case, after three months using it daily, I am not gaining any new information. In retrospective I learned, the more time for sleep is available the better. Surprise. It might have been useful to correlate 'importan factors' with metrics in the UI.
Developer response
Thank you for your honest feedback,Robert!You're absolutely right:objective sleep tracking is powerful,but its true value comes from translating data into meaningful insights.Good news:We're continuously improving our algorithm and we're currently working on an update that will show how different factors influence specific sleep metrics over time.
Most of the UI is intuitive and easy to handle. There are quite a few bugs, though, of which the two most annoying are that the app insists on falsely stating that the sleep tracker does not have enough battery power left and that the app loses the connection to the sleep tracker or is not able to communicate with it despite finding it. If you are able to get the app through your health insurance, it might be worth testing to see whether it works. I would not want to pay for it myself, though.
Developer response
Thanks for your review and for recognizing the intuitive design!Connection issue may come from another app (eg.PolarFlow)blocking access and low battery warning is meant to prevent data loss.We’d really love to help you get this working properly-just drop us a email at [email protected] you'll reconsider your rating once it's running smoothly?
amazing app with polar H10. sleep diary makes it all the more like an experimental lab.
Developer response
THANK YOU so much for the 5 stars! It’s great to hear that you're enjoying Sleep² with the Polar H10 and that you recognize how close it comes to a real sleep lab experience. That’s exactly what we’re aiming for :)
The app lacks a sleep data export feature, which is essential for long-term tracking. Please consider adding this functionality. I’ll happily update my rating to 5 stars once it's available.
Developer response
Thank you so much for your feedback, Anand Francis! You're absolutely right, a sleep data export feature is important . we’re happy to share that it’s already in development and will be available soon. Knowing that you'd rate the app 5 stars is great and means a lot to us :)
Such a well-designed and powerfully helpful app! When paired with one of the recommended devices it also provides one of the most accurate consumer-device data on the market.
Developer response
Thank you so much for your kind feedback, Fakey McGee! We're truly grateful that you value the combination of thoughtful design and scientific accuracy — especially that you recognize the level of precision sleep² offers compared to other options on the market. Thank you for being part of the Sleep² community :)
Extremely usefull. Finally after trying many other much more expensive options,I found the perfect sleep tracker .It is the closest product on the market to the gold standard of sleep testing/sleep clinic/hospital test. Sleep2 combined w/ Polar Verity Sense has been proven (by the Quantum Scientist ) against very expensive eeg machines and nearly every other consumer sleep tracker product on the market ,and it shown / unbiased to be the best. Thank you Nukkuua & Polar .Sincerely Anthony Hebert
Developer response
Thank you so much for your amazing review, Anthony – we’re truly grateful for your kind words and support! It means a lot to us that you’ve found value in Sleep² after trying so many other solutions and we deeply appreciate your recognition of the scientific quality behind our approach. Thank you for being part of the Sleep² community :)
I'm a paying user. It says it works with health connect but only to import data from health connect which is nonsensical because I want Sleep2 to track my sleep not use other sleep data in health connect. The value is in exporting the data not importing. This app is groundbraking accuracy wise but it's made by an incompetent app team
Developer response
Many thanks for your feedback!Sleep² achieves its accuracy by analyzing raw data from a Polar sensor with our scientifically validated algorithm.To cover other needs (e.g. users without Polar), sleep data can be imported via Health Connect. We're happy to say: Export feature is already in development and will be available soon.Hope you'll like it:)
Subscription based app. No possibility for life time license.
Developer response
Hi Vadik! We're sorry to see a 1-star rating, but the fact that you're asking for a lifetime license shows you see real value in sleep² – and we truly appreciate that. Please note that a free version is available and subscriptions help us continue improving the app. If you’ve enjoyed it otherwise, we’d be happy if you'd reconsider your rating? :)
Great app. The algorithm seems reliable, however sometimes the data from some nights is lost irremediably for unknown reason...
Developer response
Hello Emanuele, thank you so much for your kind words and the great feedback :) We're glad to hear you trust the algorithm, but we're truly sorry about the occasional data loss-that shouldn't happen. Please feel free to reach out to us at [email protected] so we can look into it together and help prevent it in the future.
Health Connect integration within the app is poorly utilised. Lacks integration with other fitness applications. Features for non-subscribers are minimal. Subscription plan pricing isn't realistic. Has trouble opening after being closed on Android 15. Whilst sleep tracking, you don't get any notifications regarding sensor connectivity.
Developer response
Thank you Joe, we highly appreciate your constructive feedback!Due to the character limit we can’t go into detail on every point, but several aspects are already in progress and will be addressed in upcoming updates. We’d love to hear from you directly at [email protected], so we can take a closer look at your experience and support you personally.
I really like this app and scan your dreams
Developer response
THANK YOU SO MUCH, Maria :) We're really happy to hear that you enjoy using Sleep²! If you ever have feedback, ideas, or questions - feel free to reach out to us at [email protected].
Great interface and presentation of the (seemingly quite accurate) data. Integration with Polar Verity Sense works flawlessly and unobtrusive to wear the entire night. Haven't tried it with the H10 as I find the chest belt uncomfortable to wear over longer periods. Only issue I see is with naps and biphasic sleep not being considered but that is probably by design with this specific algorithm.
Developer response
Hi Daniel,many thanks for your lovely feedback-we truly appreciate it:)We're happy VeritySense integration works smoothly and that you enjoy the interface and data quality.You're right:naps/biphasic sleep aren’t yet fully supported,but good news:we're working on improving that.Thanks for your trust and being part of the community-it means a lot!
So far, it's working well!
Developer response
Thanks a lot for your 5-star rating:) Great to hear it’s been working well so far - we’re excited to accompany you on your sleep journey! If you ever need anything, just let us know at [email protected]
useful insights. However, I find it not convenient to sleep with a chest strap. I only used it for a month to get quality sleep data.
Developer response
Thank you for your feedback and for recognizing the overall value of the app! We're glad it provided you with meaningful insights:) We completely understand that sleeping with a chest strap isn’t ideal for everyone — many users find the Polar Verity Sense much more comfortable. If you have any questions, feel free to reach out at [email protected]!
This a very useful and well put together app, early experiences are very good with some lack of context clarity here and there in the guidance on what the results mean and setting up sensor. Will update this review after more time using the app.
Developer response
Thanks for your feedback, Stuart! We're glad to hear your first experience with the app has been a good one :) We really appreciate your note about the need for more clarity in some areas and will definitely keep working on that. Looking forward to your update - and feel free to reach out anytime via email at [email protected]!
crashes lots on me new Samsung Galaxy 25
Developer response
Hi Chris, many thanks for the feedback and for flagging the issue! We're sorry to hear you're experiencing crashes on your smartphone - that’s definitely not the experience we want for you. Please reach out to us at [email protected] so we can take a closer look and help resolve this quickly.
All you get with the free version is: Sleep duration, efficiency, and continuity. Due to relatively recent changes, it seems the free version no longer offers proper insights like it used to. Previously, sleep stages were included for free. Based on what I've read, the "guidance" the pro version offers is free online videos, and general data trends. I would not recommend enabling their greed. They could've improved the Pro version, without having to limit the free version to leftovers.
Developer response
Thanks for sharing your thoughts,Andras!We're sorry to hear the recent changes were disappointing-our goal was never to take away value, but to build a sustainable path for ongoing development rooted in scientific quality. Paying users help make this possible and benefit from the full experience.Apart from pricing,how would you rate the app itself?
Hard to evaluate, because there are hidden capacities that are only available to paying customers. Should offer the possibility, from 7 to 10 days, of having a full experience, so that we all could be capable of seeing if this app is useful or not. Used with Polar Verity Sense. Responding to feed-back from developper: Yes. But I think that you would probably have more users if they could evaluate the app seeing all the metered parameters, even in a 2 to 3 days time limited full access use. YMMV
Developer response
You can explore the app for free, since some basic sleep parameters like sleep duration and efficacy are visible without a subscription. But we totally understand the wish for a fuller trial and are considering ways to improve the first-time experience. We highly appreciate your feedback, thanks a lot!
Great app, I did decide to use it because of 'The Quantified Scientist' recommendation to be the most accurate in sleep phases recording and I am really satisfied. But the pricing...maybe for someone who earns USD it is ok but in PLN its more than most streaming services (comparing to most expensive plans!). I do understand that app provides extremely accurate data based on science research but still..I think lower pricing means more users ergo more user data to analyse? maybe nots the point
Developer response
Thank you, Artur! Great to hear you're happy with the accuracy:) We understand the pricing concern, it reflects years of research and ongoing development (e.g. factor analysis, sleep apnea screening). But we're also working on making Sleep² more accessible while maintaining quality and scientific standards. Thanks for your support!
Original review: I love this app. It works with a (relatively) cheap, comfortable to wearninnbed and very accurate sensor and doesn't require a smartwatch. It's very simple to use and gives useful advice on how to improve your sleep. Edit: Sadly, without warning that the subscription was ending, from one night to the next, the app locked me out of all my recorded data and stopped functioning. This is really NOT OK. Devs: you need to warn the user! And what about my months of sleep data??
Developer response
Thank you Bubba Joe, it is really great how you appreciate our app!!! If you like, feel free to send us an email to [email protected] - we are curious about your ideas for improvement :)
Only work with Polar devices even though other ANT+ devices provide the same heart data over the same interface. It's like the developer went an extra mile to lock the app to Polar brand while not disclosing it before people pay for the service and provide their personal data.
Developer response
Thank you for your feedback, Daniel! You're right- Sleep² currently works with Polar devices (H10 and Verity Sense), as only a few wearables allow access to the raw heart data we need for accurate sleep stage analysis. But we’ve also implemented data import from Apple Health and Google Health. Would that work for you?
Pretty accurate sleep tracking. Highly recommend it
Developer response
Hi Brian! Thank you so much for your kind words and recommendation! We're really glad to hear that you're happy with the accuracy of Sleep². If you ever have questions or suggestions, feel free to reach out via [email protected] - we're always here to help:)
Very accurate and informative works with polar sensor, a bit pricey but it worths if you already have the sensor.
Developer response
Thanks a lot for your review! Great to hear you find the combination with the Polar sensor both accurate and informative. We appreciate your honest comment on the price – and we’re glad you feel it’s worth it :)
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