Endurance athletes need vitamin D says Total Body fitness

Total Body Fitness Explains the Importance of Vitamin D for Endurance Athletes
We are only just beginning to understand the complexity and importance of vitamin D in relation to health. Of importance to athletes is the function of vitamin D as it relates to overall health, bone density, innate immunity, muscle wasting, and exercise-related inflammation and immunity. To train and race optimally, an athlete should not have any nutrient deficiencies.
Bone Health:
Deena Kastor, Olympic Marathoner, broke her foot in Beijing during the 2008 Olympic Marathon. It was discovered that her calcium levels were normal, but her 25(OH)D levels were reported to be around 15 ng/ml. And Kastor lives in sunny California. Because of an early scare with skin cancer, she is known to apply sunscreen for all of her outdoor runs, thus limiting her ability to manufacture vitamin D from sun exposure. Even with the extensive research to show vitamin D and calcium’s role in preventing osteoporosis, elite, college, and high school athletes continue to be deficient in one or both nutrient(s). Stress fractures are quite prevalent in runners and yet so preventable.
Increased VO2 max:
German research studies dating back to the 1950s show that athletes exposed to vitamin D-producing ultraviolet light had improved athletic performance. Other studies showed that athletic performance peaked at the end of the summer. Peak performance was also associated with 25(OH)D levels around 50 ng/ml. In addition, maximal oxygen uptake was found to drop when less ultraviolet rays reached the earth, for example, in the late fall. This is particularly a problem for marathoners training through the summer for fall marathons.
Reduced Inflammation:
After intense exercise, endurance athletes experience inflammation due to elevated levels of pro-inflammatory cytokines. Vitamin D reduces the production of these cytokines while increasing the production of anti-inflammatory cytokines, thereby speeding the recovery process between hard workouts.
Improved Immunity:
In a February 2009 study published in the Archives of Internal Medicine, vitamin D3 levels were tested in 19, 000 Americans. Those with low levels of vitamin D had the highest incidence of colds and influenza. This is important information for endurance athletes who strive to balance heavy training loads and staying healthy.
What can be done?
1. Get regular, safe, twice-daily (5-30 minutes) exposure to sun between the hours of 10 am and 3 pm. Note that sunscreen and glass (being indoors) reduce or block UV energy.
2. Supplement with 1000 IU to 2000 IU of vitamin D3 to maintain normal levels.
For those living or competing in northern latitudes (north of Atlanta, GA) little to no vitamin D production will occur, so consumption of fortified foods and supplements is a necessity