To start off with, before mentioning what I like about a little daily sun exposure (Around a half hour at most with most of my skin expossed) I should mention that more than that should probably be avoided for most people depending on your goals. Especially if you are looking to look young since sun exposure is likely one of the biggest factor in making someone’s skin look older then it might/should be. And also simply due to reduced chances of skin cancer from over exposure to UVC rays (which sunscreen does not reduce).
Having said that, I do have a few reasons that make me think that small daily 10-30min sun session are at least worthwhile for myself to start my day and probably many others that want to get most of the potential benefits of sun exposure without the negatives that might come from being outside too much over a lifetime.
1) Getting natural Vitamin D from your bodies own production to reach normal Blood levels
No doubt Vitamin D is very important for our body so if you do not get sun exposure or your levels in blood tests are too low you definitely want to supplement with vitamin D3. Of course only IF you do not go outside enough or your live in an area without proper year long sun exposure. Anyway, Vitamin D3 which is the most common and effective form in supplements usually is collected on the skin of sheep after they’ve been exposed to the sun. It’s definitely a good way to increase in humans their blood levels of Vitamin D for blood tests but I wonder if there are other benefits that come during the full production of the vitamin D hormone in our own body that we bypass if we get our vitamin D from supplements (which I definitely recommend if your vitamin D levels are low, unlike some other vitamins it seems clear vitamin D supplementation is preferable to being deficient especially for those living in areas with cold seasons).
Just 10-30 minutes of sun exposure if you have a lot of skin exposed to the body has been shown to produce a lot, most likely at least 10,000 IU (but can depend on many factors like skin type as well) and if you make more your body can store it for longer. So you can easily just go every 2-3 days if you worry or don’t have the time for more sun exposure.
Do not wear sunscreen for these small sessions! This will block your Vitamin D production anyway as this research paper shows, and anyway I think sun screen should only be used for days that you have no choice but to be outside in the sun for many hours (day at the beach with friends/family)
A final note that might me of concern to some that like to get their sun exposure while swimming is that it looks like washing our body after or during being exposed to the sun’s ray’s might diminish or interrupt our bodies absorption of the final vitamin D product as the “previtamin D” on our skin gets washed away as it is made.
It’s not enough evidence to prove it personally, but I like to make sure sometimes when I go read at my condo’s swimming pool to get some sun I don’t go swimming/shower for a few hours after, just in case… Your body can make a lot of vitamin D in a little time if your have a lot of exposed skin and especially if you are closer to the equator. (I am currently in Thailand so definitely no problem year long). I think making sure one of my daily 20 min reading sessions I don’t go swim once a week is probably enough so I don’t really worry about it. I’m pointing this out if some people would have the idea of doing their 20min sun exposure with a morning swimming session or something. It might be good to get your levels checked and make sure they are still at 50(OH)D nmol/L.
2) The sun emits far infrared rays that might be beneficial in small quantities.
Similar to far the infrared rays in Saunas which probably have good health benefits getting sun ray exposure probably allows us to match some of the same health benefits as a session of far infrared saunas (however for me definitely not a reason to do more than 20-30 minutes, there might be risks with too much exposure in Saunas, or maybe not I haven’t seen evidence on either side but for myself I don’t see any reason to do more especially in the sun with UVC rays)
As a side note, Infrared rays are also naturally made by our own body (and make our body emit heat, but we do not notice it day to day) and this is what nightvision googles try to detect that our naked eye cannot.
3) It’s a great way to start your day or take a break and reduce stress.
Finally, what leads me to think our body rewards us for some sun exposure is that I often get a medium natural “high” after 15-30 minutes of reading in the sun shortly after I wake up. I walk back inside and I definitely feel fired up for work in a calm/stress free way. I also like to do it shortly after I wake up to make sure my body gets sunlight and it wakes up my circadian rhythm that the sun is out but I could see early risers enjoying it in the afternoon after work or to take a break.