I'm 64 and my Vitamin D Deficiency most likely started many years ago! For 22 years I was on Submarines in the U S Navy then played electrician for 22 more in office buildings and so on. About 4 years ago I was stung on on my arm buy a wasp within a few days I looked like Popeye, got mega shot swelling went down, was told to cover up when I went outside so now I have a bug issue to go along with no sun issue. but like many others I kept thinking all my alements must be age related so I just kept going on. A little over 2 years ago I stoped smoking and all hell broke lose within a few weeks I started having major health problems, High Blood Pressure, anxiety, eye, ear, neck, breathing and many other problems. Had this test that blood work head CT take this pill and that pill anxiety meds, End of 2014 seen Doctor #4 (already fired 3 doctors) my calves were cramping real bad, no sleep, weak and so on. more blood tests. Vitamin D was at 8ng/ml, " WHAT THE" Whats Vitamin D do? I started reading and reading and reading some more, boy was I blind for many years when it came to the one thing in this world of ous that can make you feel good and keep you healthy Vitamin D!!!! Doctor started me on 50,000iu D2 in Jan 2015 I said NO to the D2 and started on 7000iu of D3 added 400mg Mag glycinate. Spent most of January and February with bone pain, get out of bed few hours later back to bed, early March I was up to 16ng/ml, April 1st 2015 look up in the sky, its a bird its a plane no its the "SUN". Dam the Torpedo's full SUN ahead! Found a smart phone APP called DMINDER it logs all your Vitamin D and tells you best times for SUN. So every day if it's Sunny and warm I am in swim trunks in noon day SUN for 20 to 30 min plus I am still on the 7K D3 and mag an will be for ever. Today March the 24th I'm feeling at least 50% better.