Time in sun (in Spain) to get 4,000 IU of vitamin D: half hour in July , 2 hours in October

Created September 2016

Solar ultraviolet doses and vitamin D in a northern mid-latitude.

Sci Total Environ. 2016 Sep 21;574:744-750. doi: 10.1016/j.scitotenv.2016.09.102. [Epub ahead of print]

Serrano MA1, Cañada J2, Moreno JC3, Gurrea G4.

1Solar Radiation Research Group, Universitat Politècnica de València, Camino de Vera s/n, 46022, Valencia, Spain. mserranj@fis.upv.es.

2Solar Radiation Research Group, Universitat Politècnica de València, Camino de Vera s/n, 46022, Valencia, Spain.

3Solar Radiation Research Group, Universitat Politècnica de València, Camino de Vera s/n, 46022, Valencia, Spain. jcmestev@fis.upv.es.

4Solar Radiation Research Group, Universitat Politècnica de València, Camino de Vera s/n, 46022, Valencia, Spain. gongurys@csa.upv.es.

PDF indicates 25% body exposed in summer and 10% in winter - reasonable Abstract does not mention 3 times longer time in the sun is needed if * darker skin (they had assumed skin type III) * elderly (they had assumed 22 year old) * wear lots of clothes (they had asumed 25% skin exposure in summer) See also VitaminDWiki * 1400 IU of Vitamin D from Summer noonday German sun from a 10 minute walk – Feb 2018 similar results to the study on this page * Canadians have a hard time getting 1,000 IU of vitamin D from the sun – July 2015 * Even small amounts of UVB result in increased vitamin D levels – March 2012 * UV, sunshine, and vitamin D (87 charts) - Holick March 2013 * Optimize vitamin D from the sun many ways to increase vitamin D for the same number of minutes * Large variability in response to UV (more than response to oral Vitamin D) – March 2016 * 1400 IU of Vitamin D from Summer noonday German sun from a 10 minute walk – Feb 2018 * Little Vitamin D generated by face and hands - June 2015 * skin production is NOT the same everywhere on the body * Noontime sun and D **category listing has items along with related searches** No – 10 minutes per day of sun-UVB is NOT enough {include} It also has the following study by McKenzie

Latitudes: 40 Valencia and Beijing, 52 Berlin, 55 Edmonton and Moscow, 61 Alaska 1. Another study in 2017- not as good, for Equador Calculation of the Sun exposure time for the synthesis of vitamin D in Urcuquí, Ecuador 📄 Download the PDF from VitaminDWiki

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Solar ultraviolet (UV) radiation is one of the most important factors in the development of skin cancer in human, solar erythema and skin aging. Nevertheless, numerous studies have shown the benefits of UV solar radiation in moderate doses, such as the reduction of blood pressure and mental health, treatment of various diseases, and the synthesis of vitamin D in the skin. This paper analyses data from solar ultraviolet erythemal (UVER) irradiance in W/m2 measured in a northern mid-latitude as Valencia (Spain) for the period 2003-2010. To estimate effective solar UV radiation in the production of vitamin D (UVD) we used the relationship proposed by McKenzie et al. (2009) . It was obtained for one month for each season the minimum exposure time needed around solar noon and at 9 UTC and 15 UTC (Coordinated Universal Time) to obtain the recommended daily dose of 1000IU. Also, it has been calculated time for erythema induction around solar noon for the same months. The median UVER daily dose during the summer months was 4000J/m2day, and 700J/m2day in winter. With regard to UVD, the median UVD daily dose in summer season was 7700J/m2day, and in winter it was 1000J/m2day. Around noon in January it takes more than two hours of solar exposure to obtain the recommended daily dose of vitamin D, whereas the rest of the year range between 7min on July and 31min on October. For the same months around noon, exposure times to produce erythema were obtained, these being of higher value to the previous. The results show that it is difficult to obtain the recommended vitamin D doses in winter in a northern mid-latitude, as the human body is almost entirely covered in this season.

Tags: Sun