Reply To: I am 55 years old and 165 lbs.The last 18 years until January 2017 i had flu only one time,but since January i had flu 5 times.Μy vitamin D level is 34.is there a chance that the reason i had flu so many times is my vitamin d level?
Wow to the 75 miles per week! Congrats!
Muscles use a lot of Vitamin D. I do not think anyone has “proved” yet that you would need even more than the 5000iu a day if they did what you do. Having said this, I don’t think anyone is rushing to answer this question.
So you might have to “experiment”. If I were you, I would start with the 5000iu a day. See how you feel and if you are still getting sick after 8 weeks. If things are going well then if you want to try 10,000iu a day and see if anything improves even further. (Maybe faster run times or something else.) The 10,000iu is perfectly safe!
By all means, come back and tell me what happens.