Living a more circadian-effective life involves more sunshine. Increasing sun exposure can cause problems–but you can avoid them if you are smart and careful

First, if you are new to my publication and circadian rhythms, I recommend some nighttime changes before increasing sunlight. The nighttime changes are risk-free (unlike sunlight), and can cause immediate positive change. They include:

1. Dimming the lights to below 10 lux after sunset and for the 2-3 hours before bedtime

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2. Eating dinner before sunset and fasting the 2-3 hours before bedtime (and fasting until dawn)

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Check out my posts Circadian-Effective Interior Design and Circadian Fasting to learn more about why I think these should come before increased sunlight. Then, come back and learn more about dminder and smart solar exposure.

Is dminder worth it?

The app dminder is worth it (to me) for the ability to know the local UV index at any time. This is also helpful for traveling, since you can update your location at any time.

I use the dminder reminders for when the sun is within the possible Vit. D window for the day. This is especially helpful in the times of year when the Vit. D window is small (leading up to and following Winter). If you live outside of 30-35 degrees in latitude, there will be a part of Winter when you can't generate Vit. D from the sun at all. Your ability to recycle Vit. D through the Winter may or may not be enough to stay healthy. For people with polar heritage, Vit. D stays in the body and recycles itself for months. For example, we have not yet discovered an upper limit for Vit. D recycling in Norwegians

Synthetic Vit. D in supplements comes from irradiated fats from either lichen or lanolin. To avoid purges, traditional Vit. D foods might be a better bet than those irradiated supplements. These foods include wild-caught fish

Whatever your approach to Vit. D in the Winter, dminder can help you stock up on solar Vit. D during the times of the year when it is available. The app has definitely saved me from some Springtime sunburns. I know this is true because several times I ignored the “flip” and “get out of the sun” warnings in the app and ended up sunburned.

Even though I use dminder, sunbathing is about more than Vit. D for me. It’s about solar exposure as a whole, and doing it in a sun-smart way. If you are skeptical about the benefits of sunbathing, my post U Need UV might be a surprising read. And, of course, there is also benefit to sunbathing without UV, which I will share more about later in this review.

What does dminder do?

Dminder uses your location to give an estimate of the UV index at present, and a forecast for the upcoming week and year. If you input your skin type, it will give you a prediction for how long you can stay in the sun without sunburning. This is part of the timer feature. When you start the timer, you are also prompted to input how much of your skin is out (not blocked by clothing) and how much of the sky is clear. Then, it estimates how much photosynthesized Vit. D you can get right now and how long you can stay out without getting a sunburn. It’s pretty neat!

One thing to note—you cannot synthesize Vit. D if you are wearing sunscreen. So, make sure not to wear it for your sunbathing sessions or you won't get accurate readings.

Without sunscreen, a fair skinned person can generate thousands of IU’s in just 15 minutes if the UV index is high. It's one thing to read that, and another to see that in the app while also experiencing what Vitamin D generation feels like in the body!

This app allows you to try sunscreen-free sunbathing with "training wheels". If you are new to this, my post about building a solar callus might also be helpful.

If you buy the premium version of dminder, it tracks your estimated blood Vit. D level based on how much sunbathing you track. You can make it more accurate by adding blood test results and supplementation/diet. I don’t use this feature, so I don’t have much to say about it.

Does dminder work?

Yes, dminder helped me learn how to listen to my body while building up my solar callus. I recommend it to anyone who wants to start getting more sunlight for any reason.

Alternatives to dminder

As a rule of thumb, you can only generate Vit. D while the sun is 30 degrees (some say 35) or more above the horizon. An easy way to test this is by looking at your shadow. If your shadow is shorter than you, you can generate Vit. D (and get a sunburn if you stay out too long). If your shadow is longer than you, there is insignificant UV. This is the time you can soak up infrared rays, but not generate Vit. D.

Screenshots from the dminder app

Here’s what the dminder app currently looks like when you open it:

Here are a couple of helpful learning/teaching graphics from inside the app:

And they generate an annual forecast for your location/latitude:

Videos about dminder

Here is a video dminder put out to help people learn about the app:

And there is a walkthrough of the dminder app on their website here.

How could dminder improve?

I love dminder for what it is. One thing they could improve upon is their education (and add tracking) for non-UV exposure. People are turning to artificial red light therapies for photobiomodulation (PBM), photoprevention, and mood. These frequencies come from the sun for free and with less danger than from artificial bulbs.

Here's an excellent paper about this:

Infrared And Skin: Friend Or Foe?

967KB ∙ PDF File

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In the last decade, it has been proposed that the sun's IR-A wavelengths might be deleterious to human skin and that sunscreens, in addition to their desired effect to protect against UV-B and UV-A, should also protect against IR-A (and perhaps even visible light). Several studies showed that NIR may damage skin collagen content via an increase in MMP-1 activity in the same manner as is known for UVR. Unfortunately, the artificial NIR light sources used in such studies were not representative of the solar irradiance. Yet, little has been said about the other side of the coin. This article will focus on key information suggesting that IR-A may be more beneficial than deleterious when the skin is exposed to the appropriate irradiance/dose of IR-A radiation similar to daily sun exposure received by people in real life. IR-A might even precondition the skin – a process called photoprevention – from an evolutionary standpoint since exposure to early morning IR-A wavelengths in sunlight may ready the skin for the coming mid-day deleterious UVR. Consequently IR-A appears to be the solution, not the problem. It does more good than bad for the skin. It is essentially a question of intensity and how we can learn from the sun.

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Getting infrared on the skin in the early morning can give up to 15 SPF later in the day

Of course, as per the circadian rhythm focus here at Brighter Days, Darker Nights, all 4 quarters of the solar day matter equally.

Sunrise: red light / activates circadian systems

Noon: blue light / activates circadian systems

Sunset: red light / deactivates circadian systems

Midnight: darkness / deactivates circadian systems

Sunlight is more powerful than any known drug

Link to download dminder

Here’s their website, with links to download for your device:

Download dminder app for iphone/ipad

dminder Summary

I recommend dminder as a tool to help you learn what the different types of sunlight feel like on your skin. This is a helpful learning tool, accountability tracker, and way to stay safe under overhead sunlight.