So we built a free app that uses your Apple Watch or iPhone to automatically track your light exposure throughout the day.
It tells you if you’re getting enough, shows you how consistent you are, and rewards habits that support hormone balance.
It's in beta on TestFlight, let me know what you think!
What are you basing this on? What counts as 'enough'? And how are you tracking light exposure?
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.
> Women with active sun exposure habits were mainly at a lower risk of cardiovascular disease (CVD) and noncancer/non-CVD death
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.
If we want to see if sun exposure is the sole reason for longevity, we will have to force the subjects to sit on a couch outside.
Claiming that not getting sunlight is the same as smoking is pure garbage.
So you're throwing out a whole study because it didn't cover a specific confounding variable you thought of, than stating a claim with no evidence backing it up?
That's pure garbage.
They specifically call this out in the abstract.
> We obtained detailed information at baseline on their sun exposure habits and potential confounders.
Linearly it follows that if one wears clothes that cover more than 40% of lit skin, then the duration would be adjusted to match the total skin-area/time.
If one start with 1.85 m^2 body surface area, 40% of that is .72 m^2. If clothing covers 50% of a human and the human's shape and hair occludes half of that remaining, you have .46 m^2 available for sunlight. .72 m^2 * 20 is 14.4 m^2/min. divided by .46 m^2 it seems that 31.3 min would be the daily amount.
This seems much less than lume health's goal of 120 min. Otoh, given there is less opportunity for get to 14.4 m^2/min daily (I'm looking outside at a nice rainstorm), maybe the 120 min has some catchup factor?
I'm not saying the claim is for sure wrong, but at some point, to make this claim, someone has to have actually measured vitamin D levels in some broadly representative sample of humans and you could post that instead of whatever came up first in Google Scholar when search for "vitamin D deficiency."
https://appleheartandmovementstudy.bwh.harvard.edu/summer-da...
Couldn't find any direct source from Apple tho
A couple questions:
(1) Are you supposed to join the waitlist to use this ("Get Early Access"), or can you just start using via TestFlight ("Download Today")? I see two different links on this page.
(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?
Hit me up if you’re interested in learning more or how I can move your office space towards a renovation on the build owners dime: joseph@ledcompliant.con
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.
stek29•3d ago
- Having a dark theme seems logical for an app focused circadian rhythms, would be nice to have a dark appearance
- 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).
I hadn’t even realized that Apple had rolled out Time in Daylight — Apple Health hasn’t promoted or highlighted it like it does for other new Categories, and even then, the visualization still feels lacking.
I have been trying to get more consistent morning natural light exposure lately, so this is perfect timing!
krtkush•5h ago
Unfortunately, it is not the most accurate. If you wear full sleeved clothing which cover your Apple Watch, it will report wrong numbers.
vickipow•2h ago
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•2h ago
Appreciate the feedback. Will add those updates to our list of things to change (lots of improvements to make).
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.