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Cross Training For Runners

The Importance of Vitamin D For Runners

8 Mins read

Everyone knows that Vitamin D as a critical nutrient for bone development and health.

But did you know that it may also play a huge role in your overall recovery and athletic performance as a runner?

That’s what we’re going to cover today.

In this article, I’ll explain why vitamin D is important for runners and how to get enough each day.

Sounds great?

Let’s get started.

What is Vitamin D

Vitamin D is a key nutrient getting a lot of attention from those interested in optimal performance and health.

The nutrient belongs to a group of fat-soluble steroid-like compounds, which means that it dissolves in fats and oils and can be kept in the body for a long time.

Vitamin D can be classified into two major forms:

  • Vitamin D2 (ergocalciferol), also known as pre-vitamin D, is found in some plants, yeasts, and plants.
  • Vitamin D3 (cholecalciferol), also known as the sunshine vitamin, is the most active in the body and is synthesized in the skin following sunlight exposure.

(Of the two, D2 (cholecalciferol) is abundant in animal foods, like egg yolk and fatty fish.)

The Importance of Vitamin D

The sun is the main source of Vitamin D for most people since the nutrient isn’t commonly available in foods. That’s why this may cause problems in people who don’t get enough sun exposure.

And here’s the kicker.

Research has reported that a drastic number of athletes are Vitamin D deficient, and these low levels have dire effects on muscle endurance, strength, and power.

This is blamed on a lack of sun exposure, which is the primary nutrient source. Anything that inhibits your sun exposure can compromise vitamin D levels.

That’s why athletes who spend most of their time training indoors are especially prone and athletes who train at high altitudes.

What’s more?

Some runners may under-fuel, which can put them at a higher risk for vitamin D deficiency

Why this should be alarming?

Research has also shown that athletes with low Vitamin D levels are more prone to stress fractures and other musculoskeletal injuries. They also tend to experience higher rates of inflammation following high-intensity exercise.

In contrast, research has also reported that healthy levels of Vitamin D can positively impact muscular endurance and strength.

One example is a research review from the journal Physical Activity and Nutrition that reported that having healthy vitamin D levels positively impacts athletic performance in endurance sports—running is no exception—among other benefits.

Not only that, more and more research has found that having an increased level of the vitamin was associated with a lower rate of injuries and overall better performance in athletic performance.

Let’s dive into some of the benefits.

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The Benefits of Vitamin D For Runners

Here are some of the main benefits of having optimal Vitamin D levels.

Bone Strength

Logging the miles is stressful.

Every step you take impacts your bones. Multiply that by the many miles logged over months, and years, of training; stress fractures in your feet, shins, or femurs, are hard to avoid.

Here’s the good news. Plenty of research has linked Vitamin D deficiencies to bone-stress injuries.

The nutrient is needed for the development of strong, healthy bones. Research shows that low nutrient levels can greatly increase the risk of stress fractures.

Want proof? Here’s one.

Research published in the American College of Foot and Ankle Surgeons followed 53 subjects with stress fractures and reported that 83 percent had vitamin D levels below 40 ng/mL, and around 53 percent had levels under 30 ng/Mr.

In other words, over 80 percent of the patients had sub-par vitamin D. This is more than a coincidence.

Additional Resource – Here’s your guide to pre and post run nutrition

Immune Function

Want to veer off the cold and stay healthy all season? High vitamin D might be the answer.

Research has found a strong link between poor vitamin D levels and autoimmunity conditions. However the link between the vitamin and respiratory infection is still debatable.

Again, don’t take my word for it.

Research that looked at 225 endurance athletes over the winter reported that a drastically higher proportion of D-deficient participants experienced an upper respiratory tract infection (URTIs) such as sore throat, colds, coughs, etc. They also came down with worst symptoms than those in the healthy level group.

That’s not the whole story.

Another research reported that supplementing 5000IUs a day with vitamin D3 for a month during the cold season improved immune function and lowered the rate and severity of URTIs in taekwondo athletes.

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Research assessed 35 ultra runners, with one group receiving a big boost of 150,000 IUS 24 hours before the race and the other group getting a placebo.

Next, the researchers analyzed inflammation markers in both groups.

The result?

Both groups had higher levels of Vitamin D in their blood. This shouldn’t be a surprise since Vitamin D is released to reduce inflammation and aid in immune function.

But the group of runners who got the placebo experienced much higher markers of inflammation after the race.

Again, this shouldn’t come as a surprise

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Improved Power and Performance

Research has reported that optimal vitamin D levels can improve performance and that an increased intake can boost some strength and power measures in athletes.

Research has shown that optimal vitamin D levels can positively impact endurance performance and muscle strength.

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The Risks of Low Vitamin D

Since optimal levels of vitamin D play so many important roles in the body, a lack can definitely affect endurance and strength and boost injury risk.

Again, don’t take my word for it.

Research has reported that athletes in The National Football League (NFL) with low levels of nutrients were at a higher risk of bone fractures.

Another research found that over three-quarters of patients with ligaments and cartilage injuries and half of the patients with muscle and tendon injuries have poor vitamin D levels. This is another proof of the increased injury risk caused by lack of nutrition in this area.

That’s the whole story.

Poor vitamin D levels can also boost your risk of muscle weakness, muscle myopathy, and chronic fatigue. This is especially the case for long-distance runners.

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Symptoms of Vitamin D Deficiency

Though not everyone experiences symptoms, red flags of poor vitamin D can include:

  • General aches and pains
  • Chronic fatigue
  • Muscle weakness
  • Being prone to frequent infections

A blood test is the best way to check for vitamin D deficiency.

To err on the side of caution, consult your doctor if you suspect that you might be D deficient or have any health issues.

benefits of vitamin d for runners

Female running in mountains under sunlight.

High-Risk People

If you fall into any of the following three categories, there’s a strong chance of having low vitamin D:

  • If you spend a lot of time indoors
  • If you have dark skin
  • If you live farther away from the equator

How Much Vitamin D Runners Need?

The recommended daily allowance for vitamin D differs from country to country, and it’s often within the 400IU to 800IU per day.

For example, according to the Institute of Medicine, the recommended daily allowance is about 600IU per for those younger than 70 years old and 800IU per day for those over 70 years old.

However, some research suggests that 400-600IU per day might not be enough for optimal bone health in athletes. Instead, the research has pointed out that athletes may need to take in roughly 2000 to 5000IU a day from various vitamin D sources to meet their daily needs.

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How To Get Enough Vitamin D

Take the following steps to ensure optimal levels of Vitamin D.

Get More Sun

Diagnosed with vitamin D deficiency? Then your first step is to get more sunshine. The rule of the sun is ensuring healthy vitamin D cannot be overstated.

Research shows that with just a quarter of your body’s skin exposed to sunlight, you can synthesize enough of the nutrient for one day with around six minutes of sunlight exposure in the midday sun.

That’s why, as a runner, if you tend to run early in the morning or at night, consider switching to lunchtime runs. I’d also recommend scheduling your training between 10 am and 4 p.m.

Keep in mind that the more your skin is exposed, the higher the chance of making enough vitamin D, so reveal your legs and arms but avoid getting sunburn or frostbite.

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Diet Sources

As previously stated, your diet isn’t the most reliable way to get vitamin D, but eating there right foods does help.

Only a limited range of foods contain vitamins. These include:

  • Eggs
  • Meat
  • Oily fish such as trout, salmon, and sardines
  • Fortified milk

Remember that vegetables, grains, fruits, nuts, and cereals pack very little vitamin d—sorry, vegans.

When To Supplement

If you are at high risk for a deficiency, I’d strongly urge you to take a daily vitamin D supplement.

The truth is that supplementing with vitamin D can boost physical performance strength and reduce injury risk, especially in those who lack the vitamin or are at low levels.

Some health agencies suggest that everyone should be supplemented with vitamin D, especially during the winter, thanks to minimal sunshine exposure from cloudy weather conditions and spending too much time indoors.

According to NOW, the standard recommended level for Vitamin D maintenance is around 2000 IU/day—that’s around two dollars per month, so it’s pretty cheap.

Ideally, opt for a supplement that contains vitamin D3, which is the more readily available form.

The nutrient often comes in oil-based capsules, but if you take it in powder form, make sure to consume fatty foods to boost absorption.

The only time you should think twice before supplementing is if you have any health conditions predisposing you to hypercalcemia (high calcium levels in the blood), sarcoidosis, granulomatous disease, lymphoma, Lyme disease, kidney diseases, or if you’re under certain medications. Your doctor will know better.

Does Supplementing Work?

Research out of the Journal of International Society of Sports Nutrition assessed the impact of vitamin D supp on the skeletal muscles of endurance runners.

This research assessed how the subjects’ bodies reacted to supplementing over a 3-week period. In the end, the researchers reported that three weeks of supplementing with vitamin D positively impacted serum 25OH levels in endurance-trained runners.

What’s more?

Supplementing may also reduce post-exercises biomarkers such as creatine kinase, myoglobin, troponin, and lactic dehydrogenase levels.

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What Type Of Vitamin D Supplement To take?

So which one is more powerful and efficient?

Again we turn to research.

Research has found that D3 is the more powerful and efficient form and is better absorbed and utilized than D2

The supplement takes many forms, such as pills, liquid drops, power, etc.

Vitamin D3, or cholecalciferol, consists of the neutral form of the nutrient that your body synthesis from sunlight. It’s often made from the fat of lamb’s wool.

Be careful with supplements, as vitamin D toxicity can cause digestive issues, nausea, decreased appetite, and frequent urination.

Vitamin D toxicity

Too much of a good thing is always problematic. That’s why you should be wary if you frequently supplement with high doses—especially if you’re not under medical supervision.

The main symptoms include:

  • Muscle weakness and fatigue
  • Decreased appetite
  • Frequent vomiting
  • Dehydration
  • Calcification of soft tissue (in rare cases)

Vitamin D For Runners  – The Conclusion

There you have it. If you’re runner and serious about achieving optimal health, getting enough Vitamin D everyday should be a priority on your list. The rest is just details.

Feel free to leave your comments and questions below.

Have a great day

David D.

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