This might be the range most of us should expect to be in at an intake of 10,000 IU/d. This is the equivalent to the body’s own natural production through sun exposure.
There are other factors that may affect levels. For example, being overweight tends to reduce them. Excess cortisol production, from stress, may also reduce them.~ Ned Kock from, http://healthcorrelator.blogspot.com/2010/12/what-is-reasonable-vitamin-d-level.html
…and some days this turns into a bit of a medical blog.
This is mostly a blog post for me, so the next time I search for Vitamin D I can find this article. When Vitamin D supplementation comes up, and I mention that I take 10,000 IU daily… people ask why? …and I cannot remember why. This article from 2010 is why; 10,000 IU is about how much vitamin D my body would make if I lived somewhere sunny and I was a life guard.
(Part 13 of 14 in series, John Briffa's "A Good Look at Good Health")
In this study, muscle function was assessed in a group of 12 individuals with known vitamin D deficiency. The assessment centred around timing the replenishment in the muscle of a substance known as phosphocreatine. Phosphocreatine is a key molecule in the production of energy (in the form of what is known as ATP) by tiny ‘powerhouses’ in the cells of our body known as mitochondria (pronounced my-toe-con-dree-ah). Shorter phosphocreatine replenishment times after activity are a sign of better mitochondrial function.
Vitamin D supplementation was found to lead to a significant reduction in phosphocreatine replenishment times, signalling an improvement in mitochondrial functioning. Fatigue ratings improved in all the study participants too.~ John Briffa from, http://www.drbriffa.com/2013/03/18/vitamin-d-improves-energy-production-in-muscles-of-vitamin-d-deficient-people/
The more I read, the more I believe that Vitamin D is a keystone for my health and progress. I believe that getting more sun exposure (walking, running, and Parkour outside), combined with taking vitamin D supplements has enabled a lot of other successes: Better sleep, better immune system functioning, better mood (ever hear of “Seasonal Affliction Disorder”?) and now, some evidence that it really does affect the performance of your mitochondria — your cells little power-houses.
(Part 55 of 73 in series, My Journey)
I think it may be the sun exposure.
When I started Parkour, I wasn’t even aware that I was generally UNhappy. But I sure did notice that everyone I met WAS happy. At first I just marked this down to “everyone is young”, and I set about simply enjoying training and playing with a mob of fun people.
Then, slowly, I realized I was becoming happy.
Now sure, some of this has to be due to my changing — some life-style changes, some dietary, some weight, some exercise, etc. But the more I’ve been reading, the more I’m inclined to blame some of it on the sun.
You see, it’s been shown that Vitamin D supplementation works wonders, and I’d bet that getting my Vitamin D the natural way is even better.