Taking vitamin D may boost exercise performance, study says

Vitamin D has come to the forefront in the past few years, as its importance in everything from bone health to aiding the immune system was recognized. Now, scientists presenting to the Society for Endocrinology conference in Edinburgh may have something new to add to that list: Vitamin D might boost exercise performance, as well as lower one’s risk of heart disease.

Previously, studies have suggested that vitamin D blocks the actions of an enzyme known as 11-βHSD1—which is a key member of the pathway to make cortisol, the hormone associated with stress. High cortisol levels can raise blood pressure by narrowing blood vessels in the body and by signaling to the kidneys to retain water.

This means that vitamin D could potentially lower the amount of cortisol circulating in the bloodstream, which in turn could improve exercise performance as well as lower cardiovascular risk factors.

To test this theory, researchers from Queen Margaret University in Edinburgh launched a pilot study in which they gave 13 healthy adults (of similar ages and weights) 50 micrograms of vitamin D per day for two weeks, and gave 13 similar adults a placebo for the same amount of time.

At the end of this study, the adults given vitamin D had both lower blood pressure and lower cortisol levels in their urine than those in the control group. Further, a fitness test revealed that that vitamin D group cycled 30% further than the control group—and showed fewer signs of physical exertion.

Of course, the study didn’t have a huge number of participants, but like all pilot studies, it shows promise for future research.

“Our pilot study suggests that taking vitamin D supplements can improve fitness levels and lower cardiovascular risk factors such as blood pressure,” said Dr. Raquel Revuelta Iniesta, co-author of the study, in a statement. “Our next step is to perform a larger clinical trial for a longer period of time in both healthy individuals and large groups of athletes such as cyclists or long-distance runners.”

Maybe I should take some vitamin D?

Vitamin D is actually an extremely important vitamin—especially because it functions as a hormone, too. For example, if you get too little of it:

“Vitamin D deficiency is a silent syndrome linked to insulin resistance, diabetes, rheumatoid arthritis, and a higher risk for certain cancers,” explained lead author of the study Dr. Emad Al-Dujaili.

Moreover, it appears that vitamin D lowers risk of depression. This may actually tie into this study somewhat, as extended exposure to cortisol appears to be a cause of depression, and since vitamin D inhibits a key players in the creation of cortisol, perhaps this is the root of the protective effect.

Luckily, if you want to make sure you get enough D, there is a simple solution: Go out in the sun. The NHS recommends 10-15 minutes of summertime sun exposure daily for light-skinned individuals; for those with darker skin, more time may be needed. Winter’s indirect sunlight, however, may mean you need to supplement the vitamin, or eat certain kinds of meat, eggs, or oily fish.

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