4 ms·

i've been skiing 3-4 days/week with around 8 hrs out in the sun. Would this have the same beneficial effects on me? I am always deficient but i din't bother tak

• hyencomper 5y ago
  For Vitamin D synthesis, the sun needs to be at an angle of 50 degrees or higher. Depending on the latitude where you live, the sun may not get that high all winter so you may need to supplement.
  • tim333 5y ago
    Surely sunlight is still sunlight even if it's from a low angle?
    • lodi 5y ago
      No, the composition of sunlight literally changes throughout the day. When the sun is low in the sky in the morning or evening, light is traveling through more atmosphere than it is at noon. As light travels through the atmosphere, a certain fraction is scattered in a wavelength-dependent way. UV-B light--the Vitamin-D-causing kind--has a hard time passing through the atmosphere because of interactions with ozone molecules, so at grazing angles almost none gets through. However UV-A light is less affected by ozone and can still give you a sunburn. Interestingly, ordinary glass blocks both.
    • beagle3 5y ago
      From memory, it's not just about sunlight, but rather specific band of uv-light; and the atmosphere filters it when the sun is at specific angles. It's not as simple as "just sunlight".
• williamtwild 5y ago
  Unless you ski naked its not doing much .