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New Research Shows Vitamin D Can Dramatically Increase Athletic Performance

May 23, 2009 | 43,885 views

vitamin D, sun, sunlight, performance, exercise, workoutAccording to a new review of research, evidence suggests that adequate treatment of vitamin D deficient athletes could dramatically improve their performance. Activated vitamin D is a steroid hormone which regulates more than 1,000 human genes. Recent research indicates that intracellular vitamin D levels in numerous human tissues, including nerve and muscle tissue, are increased when inputs of its substrate, the prehormone vitamin D, are increased.

Researchers reviewed the world's literature for evidence that vitamin D affects physical and athletic performance. Numerous studies, particularly in the German literature in the 1950s, show vitamin d-producing ultraviolet light improves athletic performance. Furthermore, a consistent literature indicates physical and athletic performance is seasonal; it peaks when vitamin D levels peak, declines as they decline, and reaches its nadir when the levels are at their lowest.

Vitamin D also increases the size and number of fast twitch muscle fibers. Most cross-sectional and randomized controlled studies show that vitamin D levels are directly associated with musculoskeletal performance.


Dr. Mercola's Comments:

The study above, co-authored by noted vitamin D expert Dr. John Cannell of the Vitamin D Council, offers compelling arguments for the benefits of vitamin D on athletic performance.

Back in the 1960s and 1970s the Germans and Russians won many Olympic medals, and they were convinced vitamin D was their natural wonder drug. One study dating back to 1938 showed that 100-meter dash times were improved from 13.63 to 12.62 seconds, using vitamin D-producing ultraviolet lamps.

Another 1945 study found that UV radiation for up to 2 minutes, three times a week, improved cardiovascular fitness scores by 19 percent, compared to 2 percent for students who did nothing.

These and other facts were intriguing enough to peak Dr. Cannell’s interest.

How Can Vitamin D Improve Your Athletic Performance?

In order to understand how vitamin D may impact your athletic performance, it’s important to remember that the active form of vitamin D is not really a vitamin, but rather a steroid in the same way that testosterone is a steroid. It’s also a hormone in the same way as growth hormone is a hormone.

Says Dr. Cannell,

“Steroid hormones are substances made from cholesterol that circulate in your body and work at distant sites by setting in motion genetic protein transcription. That is, both vitamin D and testosterone set in motion your genome, the stuff of life. While testosterone is a sex steroid hormone, vitamin D is a pleomorphic steroid hormone.”

However, whereas both steroids and vitamin D can improve athletic performance, steroids are obviously quite dangerous to your health. Vitamin D on the other hand is not only safe, but also vital for literally hundreds, if not thousands of other health conditions.

So, could vitamin D be the next all-natural performance enhancing drug?


Dr. Cannell’s research shows that vitamin D increases the size and number of Type II (fast twitch) muscle fibers. And most cross-sectional studies show that vitamin D levels are directly associated with musculoskeletal performance in older individuals.

It is thought that peak athletic performance will likely occur with vitamin D levels of about 50ng/mL. These levels may also protect you from an astonishingly diverse array of other acute and chronic diseases, such as:



Heart disease



Rheumatoid arthritis

Diabetes 1 and 2

Multiple Sclerosis

Crohn’s disease

Cold & Flu

Inflammatory Bowel Disease



Signs of aging


Eczema & Psoriasis


Hearing loss

Muscle pain


Periodontal disease


Macular degeneration

Reduced C-section risk

Pre eclampsia




Cystic fibrosis



Alzheimer’s disease


According to Dr. Cannell, if you are vitamin D deficient, the medical literature indicates that the appropriate amount of vitamin D will make you faster, stronger, improve your balance and timing, etcetera. But to what degree you may see an improvement will depend on how deficient you are to begin with.

Are You Deficient in Vitamin D?

Your chance of being deficient in this essential nutrient is very high. One recent study found that even in sun-drenched area
such as
southern Arizona, people are commonly deficient in vitamin D, particularly those with darker skin who produce less vitamin D in response to sunlight.

In fact, more than a quarter of Arizona adults tested had dangerously low blood levels of the vitamin.

Based on healthy, clinically significant ranges, anything below 50 ng/ml is considered a deficiency state.

So it’s important to realize that even if you live in a perpetually sunny environment but work the entire week indoors and don’t make a conscious effort to go outside during the weekends you can, and probably will, become vitamin D deficient.
It is simply not enough to walk from your car to work and home and expect to get enough sunshine to alter your vitamin D levels.

In order to reap any and all the benefits that vitamin D has to offer you need to make sure your levels are within the therapeutic range of 50-65 ng/ml.

How do you get there?

According to Dr. Heaney -- whom I interviewed for my Inner Circle expert segment on the topic of sun exposure and melanoma, earlier this year -- your body requires 4,000 IU’s daily just to maintain its current vitamin D level. So in order to actually raise your levels, you’d have to increase either your exposure to sunshine, or supplement with oral vitamin D3.

Remember, if you chose to take an oral supplement it’s essential that you get your levels tested regularly by a proficient lab to make sure you’re within the therapeutic range and not reaching toxic levels. In the U.S. I recommend using LabCorp.

For even more information on therapeutic vitamin D levels, and vital updates on testing, please review my article: Test Values and Treatment for Vitamin D Deficiency.

Beware: Tanning Behind Glass Can Worsen Your Vitamin D Deficiency!

Last but not least, it’s also important to realize that sitting by a window, or getting sun exposure while driving your car can be more detrimental than helpful.

This is because your windows screen out the vast majority of UVB’s, which produce vitamin D in your skin, while allowing harmful UVA’s in.

UVA radiation actually destroys vitamin D
, which, normally, helps keep your vitamin D levels in balance; it’s one of the protective mechanisms your body has to avoid overdosing on vitamin D when you’re outside.

However, when you’re exposed to sunlight through windows -- in your office, your home or your car -- you get the UVA but virtually none of the beneficial UVB. This can lead to significant health problems, because in addition to destroying vitamin D3, UVA’s also increase oxidative stress.

It’s the UVA rays, not the vitamin D-producing UVB’s, thatare one of the primary culprits behind skin cancer, andare responsible for much of the photo aging of your skin.

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