Tip: Boost Performance in 14 Days with this Vitamin

Take this for just two weeks and see your endurance escalate and cortisol levels plummet.


Are you one of those gamer geeks who stays indoors a lot? Or are you someone who lives far from the equator where there isn't as much sun? Maybe you always use sunscreen, or you have dark skin, or you don't consume very much fish or milk?

If any of these things are true, you may be deficient in Vitamin D3, which is one of the most common deficiencies in the world. It's bad enough for your health if you're low in this crucial vitamin, but a deficiency can really mess up you athletic performance, too.

The Study


The study involved 15 people, 6 of whom were given placebo and 9 of whom were given 2000 units of Vitamin D3 a day for 14 days. Participants were asked to do 20 minutes of hard cycling on an ergometer, before and after taking Vitamin D3.

The following things were noted:

  1. The Vitamin D3 group cycled a greater distance than the placebo group.
  2. The Vitamin D3 group felt less tired after cycling.
  3. The Vitamin D3 group had lower resting and active systolic and diastolic blood pressure (a good thing).
  4. The Vitamin D3 group had less cortisol in their urine, along with a more favorable cortisol/cortisone urine ratio.

Why Did It Work So Well?

The scientists theorized that the Vitamin D3 lowered blood pressure because it inhibits the renin-angiotensin-aldosterone (RAAS) system. In short, stimulating the RAAS leads to high blood pressure and inhibiting it (like Vitamin D3 does) reduces blood pressure.

As far as the positive effects on cortisol and cortisol/cortisone ratios, Vitamin D3 appears to reduce the activity of an enzyme named 11-beta-HSD1, which is the enzyme that turns cortisone to cortisol.

How Much D3 Should I Take?

The cool thing about this study is that it used a sane dosage of Vitamin D3. Two thousand units is probably a perfect amount for most people to take, especially if their lifestyle (lack of sunlight in general) or dietary habits aren't conducive to healthful levels of Vitamin D3.

There are plenty of symptoms that possibly reflect a Vitamin D3 deficiency, like frequent illness, undue fatigue, depression, impaired wound healing, muscle pain, and undue sweating from the head area, but the only way to make sure you have adequate amounts is to have a blood test. (The optimal range is between 50 and 70 nanograms per milliliter.)

Regardless of whether you have overt symptoms or not, Vitamin D3 is one of those things you should be taking anyhow. It's a cheap but solid insurance policy against poor health and a poor response to training.


  1. Emad A. S. Al-Dujaili, Nimrah Munir, Raquel Revuelta Iniesta, "Effect of vitamin D supplementation on cardiovascular disease risk factors and exercise performance in healthy participants: a randomized placebo-controlled preliminary study," Ther Adv Endocrinol Metab. Vol 7, Issue 4, 2016.

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