(Part 13 of 14 in 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.
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.