# How much sunlight do i need a day... **URL:** \ **Category:** Factual Questions\ **Created:** [June 21, 2005, 8:13pm UTC](https://boards.straightdope.com/t/how-much-sunlight-do-i-need-a-day/309244 "2005-06-21T20:13:15Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![destroypower](https://avatars.discourse-cdn.com/v4/letter/d/d26b3c/32.png) [@destroypower](https://boards.straightdope.com/u/destroypower)\ **Post date:** [June 21, 2005, 8:13pm UTC](https://boards.straightdope.com/t/how-much-sunlight-do-i-need-a-day/309244/1 "2005-06-21T20:13:15Z")
Im starting to change my lifestyle to a more healthy one in every aspect. I know sunlight is good for human skin, but how much should I get a day? My grandmother said to sit out in the sun for 10 minutes a day. What would you suggest? Thanks ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [June 21, 2005, 11:01pm UTC](https://boards.straightdope.com/t/how-much-sunlight-do-i-need-a-day/309244/2 "2005-06-21T23:01:12Z")
Sunlight is absolutely not good for human skin. Exposing skin to sunlight is an excellent way to develop skin cancers sooner or later in life. What your grandmother probably is thinking of is that the human body can make its daily requirement of vitamin D with a 15 minute or so shirtless exposure to the noonday sun or the equivalent. This is not necessary today, given the ease of getting more than sufficient vitamin D through foods, especially since so many foods are fortified with it. Good diet and exercise is a combination far more healthy than exposure to sunlight. Getting some fresh air may also be a good idea, but keep your shirt on when you do so. ---
**Author:** ![Cagey\_Drifter](https://avatars.discourse-cdn.com/v4/letter/c/b2d939/32.png) [@Cagey\_Drifter](https://boards.straightdope.com/u/Cagey_Drifter)\ **Post date:** [June 21, 2005, 11:15pm UTC](https://boards.straightdope.com/t/how-much-sunlight-do-i-need-a-day/309244/3 "2005-06-21T23:15:54Z")
**Exapno Mapcase** , can you give a cite stating that little to moderate amounts of direct sunlight is bad for you? ---
**Author:** ![Reeder](https://avatars.discourse-cdn.com/v4/letter/r/c6cbf5/32.png) [@Reeder](https://boards.straightdope.com/u/Reeder)\ **Post date:** [June 21, 2005, 11:20pm UTC](https://boards.straightdope.com/t/how-much-sunlight-do-i-need-a-day/309244/4 "2005-06-21T23:20:30Z")
Moderate exposure to sunlight is essential for vitamin D creation. Especially for those whose diet is lacking in it. Best times are early in the morning or late in the afternoon. About 20 mins a day. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [June 22, 2005, 1:08am UTC](https://boards.straightdope.com/t/how-much-sunlight-do-i-need-a-day/309244/5 "2005-06-22T01:08:36Z")
I’m not saying that one must shun the sun entirely. But most authorities agree that exposure is cumulative, and that the notion that sunlight is a positive benefit has some severe limitations. No one can say that a brief exposure to the sun is harmful or will unquestionably lead to cancer. But the following advice is typical and can be found at skin cancer sites everywhere. > **[Skin Cancer | Causes, Symptoms and Treatment](https://patient.info/cancer/skin-cancer-types)** > > Skin cancer is the most common cancer in the UK. Around 100,000 cases are diagnosed each year. Skin cancers are divided into melanoma and non-melanoma. > [@](#): > > How can I prevent skin cancer from developing? > > Most skin cancers are caused by excessive exposure to the sun. We should all limit our sun exposure in the summer months (or all year when in hot countries nearer the equator) by: > > Staying indoors or seeking the shade as much as possible between 11am and 3pm. > > Covering up with clothes and a wide brimmed hat when we are out in the sunshine. > > Applying sunscreen with a sun protection factor of 15 or more to all exposed areas of skin when we are out in strong sunlight. > > In particular, children should be protected from the sun. Sunburn or excessive exposure to the sun in childhood is thought to be the biggest risk factor for the developing of skin cancer as an adult. **Reeder** , while early in the morning or late at night are the best times to minimize sunburn and the harmful effects of UV, sunning then greatly increases the amount of time necessary to be in the sun to create an equivalent amount of vitamin D. The same UV that tans and burns also stimulates the vitamin D precursor production. If you need 20 minutes at noon, then you need at least an hour at other times. You can’t get out of it that easily. [An article originally from The New York Times](http://www.supplementquality.com/efficacy/vitD_sun_exposure.html) > [@](#): > > Sunning to prevent vitamin D deficiency is like smoking to combat anxiety, experts say in response to recent reports linking the health benefits of vitamin D to unprotected sun exposure. According to the American Academy of Dermatology (AAD), the Yale School of Dermatology and the Sun Safety Alliance, these claims are scientifically unsound and mislead the public about the very real dangers of ultraviolet (UV) radiation—the leading cause of skin cancer. > > … > > The AAD says it is “deeply concerned” about the current claim by Dr. Michael Holick, director of the vitamin D laboratory at Boston University School of Medicine, that exposing unprotected skin to the sun several times a week is necessary to prevent vitamin D deficiency. Holick cites two studies that found inadequate levels of vitamin D among people in two northeastern cities where the sun’s ultraviolet (UV) rays don’t penetrate during winter months. According to Holick, always wearing sunscreen is tantamount to creating this same “winter-like” environment on the skin, causing vitamin D levels to drop. > > “I am not aware of any scientific studies that support this claim,” said Dr. David J. Leffell of the Yale School of Medicine Department of Dermatology. “In my two decades of practice, I’ve never seen vitamin D deficiency caused by lack of sun exposure due to sunscreen use, yet the evidence that UV rays from the sun cause skin cancer is overwhelming.” > > Leffell says the winter drop in vitamin D levels among northeastern residents is a normal process that is well-known and easily accommodated by dietary supplementation. He cites inadequate diet as a culprit in the “very small” portion of the population that is truly vitamin D deficient. For these people, Leffell says, deficiency can be offset by taking vitamin D supplements or drinking fortified milk. ---
**Author:** ![picunurse](https://avatars.discourse-cdn.com/v4/letter/p/7bcc69/32.png) [@picunurse](https://boards.straightdope.com/u/picunurse)\ **Post date:** [June 22, 2005, 1:21am UTC](https://boards.straightdope.com/t/how-much-sunlight-do-i-need-a-day/309244/6 "2005-06-22T01:21:40Z")
Going into the sun, even sun bathing is not an automatic skin cancer. Getting sun_burned_ increases your skin cancer risk. People with fair skin, light hair and eyes are more at risk. Sunscreen reduces the risk. Long exposure is more likely to result in a sunburn. So, moderation and sunscreen are the keys. Sunlight has been shown to reduce acne and psorisis. Since there are other, better treatments for both, it isn’t recommended. We need vitamin D it metabolize Calcium. We produce vitamin D with exposure to full spectrum light. Unless you live in a cave, never leaving it, you get enough sunlight to process Calcium. Also, vitamin D has been added to milk for as long as I can remember. Newborns are sometimes jaundiced. If they are still in the hospital, they are put under a full spectrum light for given periods each day. If they are otherwise healthy, they go home and might be instructed to expose them to sunlight for short periods each day, to help them metabolize the substance called [bilirubin](http://www.chclibrary.org/micromed/00057970.html) ---
**Author:** ![InternetLegend](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/internetlegend/32/13154_2.png) [@InternetLegend](https://boards.straightdope.com/u/InternetLegend)\ **Post date:** [June 22, 2005, 4:16am UTC](https://boards.straightdope.com/t/how-much-sunlight-do-i-need-a-day/309244/7 "2005-06-22T04:16:06Z")
I’ve always believed that the less sun exposure you get, the better off you are. However, with stories like this in the news, perhaps we shouldn’t dismiss the idea of regular, moderate sun exposure: [Sunlight May Not Be All Bad for Some Cancers](http://www.cancer.org/docroot/NWS/content/NWS_1_1x_Sunlight_May_Not_Be_All_Bad_for_Some_Cancers.asp) If the American Cancer Society is saying it, it’s worth consideration. ---
**Author:** ![Fuel](https://avatars.discourse-cdn.com/v4/letter/f/df705f/32.png) [@Fuel](https://boards.straightdope.com/u/Fuel)\ **Post date:** [June 22, 2005, 5:30am UTC](https://boards.straightdope.com/t/how-much-sunlight-do-i-need-a-day/309244/8 "2005-06-22T05:30:20Z")
My gut feeling, (which is what I use to decide on some health issues such as this one) about sunlight is that it is probably beneficial to expose yourself to just enough sunlight per week to gain a (hopefully) beneficial adaptation from it. A little color in your skin seems healthy for a reason… maybe the reason is that it IS healthy, just maybe. In doing this, I am keeping a keen eye on my spots and I have my buddy dermapathologist look at them every once in a while. 10-15 min. a day of sunlight has cleared what little skin imperfections I had (tiny, skin colored bumps) and corrected a very mild case of dry skin on my shaved head. ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [June 22, 2005, 6:40am UTC](https://boards.straightdope.com/t/how-much-sunlight-do-i-need-a-day/309244/9 "2005-06-22T06:40:52Z")
NPR had a segment about sun exposure and vitamin D on last week’s [Science Friday](http://www.npr.org/templates/story/story.php?storyId=4707987) segment of Talk of the Nation that you might find interesting.