Here's a summary of the themes from the Hacker News discussion, with direct quotes:
User Interface and Experience (UI/UX) Feedback
Several users provided feedback on the app's user interface and navigation, suggesting improvements for a smoother experience.
- A key suggestion was the inclusion of a dark theme, deemed logical for an app focused on circadian rhythms. > "Having a dark theme seems logical for an app focused circadian rhythms, would be nice to have a dark appearance" - stek29
- Another point of friction identified was the inability to easily switch between days, requiring multiple taps or non-intuitive gestures. > "Not being able to switch between days by swiping felt quite annoying: the Home page requires two taps to change to another day, and the Progress page needs one — but it could’ve been a swipe. And the calendar on the Day page can’t be swiped down, only closed by tapping on the (x)." - stek29
Accuracy and Limitations of "Time in Daylight" Metrics
A significant portion of the discussion revolved around the accuracy and reliability of the "Time in Daylight" metric, particularly as implemented by Apple Watch.
- It was noted that the metric's accuracy depends on the Apple Watch's exposure to light. > "Unfortunately, it is not the most accurate. If you wear full sleeved clothing which cover your Apple Watch, it will report wrong numbers." - krtkush
- Apple's own explanation suggests a grace period for sensor fusion to work after initial exposure. > "I spoke to the team at Apple, they said as long as you have a couple of minutes in the sunlight while you're on a walk it will then use sensor fusion to count the rest of the time outside." - vickipow
- A limitation mentioned is the need for screen exposure for a few minutes to register accurately. > "Yeah unfortunately you have to have the screen exposed for a few minutes each time you go outside." - vickipow
- The app developer acknowledged these limitations and confirmed they are working on improvements. > "Appreciate the feedback. Will add those updates to our list of things to change (lots of improvements to make)." - vickipow
- There was also a question about how the app specifically measures light exposure and whether Apple Watch sensors expose such APIs. > "(2) How does this app measure the amount of light received by the Apple Watch? Does the Watch have such sensors and expose such APIs?" - coolandsmartrr > "there is a light sensor in the display of the Apple Watch that automatically tracks it. It works ~80% of the time, but struggles if you have a big jacket" - vickipow
The Importance and Measurement of Sunlight Exposure
Users debated the necessity and definition of sufficient sunlight exposure, questioning the app's underlying claims and the scientific basis for its goals.
- One user questioned the basis for the claim that most people aren't getting enough light and how "enough" is defined and tracked. > "What are you basing this on? What counts as 'enough'? And how are you tracking light exposure?" - Fraaaank
- The prevalence of Vitamin D deficiency was cited as evidence for the need for more sun exposure. > "There are countless studies that billions of people are Vitamin D deficient. Our bodies are designed to get most of that from the sun. Lots of people never even leave their house on a given day." - snarf21
- Concerns were raised about misinterpreting studies, particularly regarding the amount of exposure needed and the risks of excessive sun. > "The study you link states that 'To prevent vitamin D deficiency, one should spend 15 to 20 minutes daily in the sunshine with 40% of the skin surface exposed.'. The screenshot on lume health shows a goal of 120 minutes." - Fraaaank > "Moreover, sun exposure is not by definition 'healthy'. Spending two hours in the sun at noon in the middle of summer does more harm than good." - Fraaaank
- Some studies were presented, but their methodology and conclusions were questioned. > "Nonsmokers who avoided sun exposure had a life expectancy similar to smokers in the highest sun exposure group, indicating that avoidance of sun exposure is a risk factor for death of a similar magnitude as smoking." - agensaequivocum > "The study seems to be incredibly flawed." - brokegrammer > "Not surprised there because people who spend more time outdoors will typically be participating in physical activity at the same time, while people who avoid sun exposure will typically be seated while participating in sedentary activities." - brokegrammer > "Claiming that not getting sunlight is the same as smoking is pure garbage." - brokegrammer
- A user pointed out the difficulty in finding a direct source from Apple regarding the "Time in Daylight" metric. > "Couldn't find any direct source from Apple tho" - wonger_
- The app developer emphasized that they are working on a wearable hormone monitor that directly links sunlight to hormones, seeing this as a powerful lever for behavior change, and using the "you can't improve what you can't measure" adage for the app. > "The product we're working on in the background is a wearable hormone monitor that actually shows you at the molecular level how much sunlight impacts your hormones - we've found this to be the most powerful lever for behavior change. But in the meantime, we have been using the saying "you can't improve what you can't measure" to help people get more sunlight." - vickipow
Broader Implications and Skepticism
Beyond the app itself, the discussion touched upon the broader societal trends and a general skepticism towards relying on apps for fundamental biological needs.
- There was a call for more robust, actual data rather than opinion pieces when making broad claims about deficiencies. > "Where is the data here? That article simply declares that there is a global epidemic of vitamin D deficiency and I followed the citation it gives to back that up, which is this: [...]. Except this citation is also not a study. It's an opinion piece that just declares people are vitamin D deficient without doing any measurements of how much vitamin D anyway has circulating in their blood." - nonameiguess
- The perceived disconnect from natural biological signals was highlighted. > "ummmmmm, if you dont have some kind of tan lines, you are not getting enough sunlight the app is pre loaded at birth .......though,I get it, as there is a significant demographic who will only trust there (beloved) device, and will benifit from the prompt, perhaps, perhaps not, as there is no possible way to break out all of the inumerable ways that human phisiology has adapted to ambient conditions on our planet, into seperate apps, so....." - metalman > "I'm with metalman on this." - tolerance
- The need for users to have their phones exposed to light, in addition to changing habits, was seen as a potential hurdle. > "Most people have their phone in a pocket or purse or similar while outdoors. Wouldn't this require the phone to be out and exposed to light in order to work correctly? So not only are you trying to get people to change habits of getting outside, you're also requiring they change habits with the devices as well. Good luck with that, and I mean that with more sincerity than snark but not no snark." - dylan604
- The app developer acknowledged the goal of improving behavior and highlighted the importance of morning light. > "Glad to hear you're getting more consistent morning light, it's imo one of the most powerful things you can do for your health." - vickipow
Platform Availability and Future Development
There was a clear request for cross-platform availability and an indication of future development plans.
- Users expressed a desire for an Android version of the app. > "Nice! An Android version would also be appreciated :)" - justmarc
- The developer confirmed they are working on an Android version. > "Working on it! Thanks for the feedback." - vickipow
- The app is also linked to a hardware product for hormone monitoring. > "You can join the waitlist for our hormone tracking device, the app is available for download today on TestFlight. Eventually the app will be used to show you the connection to your hormone balance (like cortisol etc.) and your light exposure. They are very tightly linked!" - vickipow