How Getting Outside for Some Vitamin D Can Improve Your Fitness

running outdoors
Soldiers from Headquarters Support Company, Eighth U.S. Army, conduct sprints using sandbags as distance markers as part of their outdoor physical training during the Ulchi Freedom Guardian 2013 exercise. (Photo by Spc. Anthony Zane/362nd Mobile Public Affairs Detachment)

If you simply get outside for a few minutes each day, the sun will create a mysterious vitamin in your body that will bring enormous health benefits. If you live somewhere without much sun, you can also eat foods rich in vitamin D.

Vitamin D is considered a "steroid hormone" that regulates your level of calcium, phosphorus and bone growth. The vitamin D also improves hormone synthesis, stronger bones, immunity strengthening, energy levels and even mood.

Here is a list of ways to improve your vitamin D numbers. As with anything, too much of a good thing is not good, In fact, it can be quite unhealthy if you get too much vitamin D.

1. Get Some Sun

Sitting in the sun with your skin exposed for 15-20 minutes is sufficient. Wearing a bathing suit and no sunscreen will do the trick. Studies show the body can create up to 10,000IU (international units) of vitamin D by sitting in the noon sun for just 30 minutes. That is more than 10x the recommended dosage. Those with sensitive skin may want to only do 5-10 minutes of direct sunlight to avoid dangerous skin conditions while still getting enough sun to make vitamin D.

2. Eat Foods with Vitamin D

When on a normal healthy diet, most people will get 10%-15% of their vitamin D from the foods they eat. Many foods and drinks are fortified with vitamin D, and these foods are highly recommended, especially if you are not able to get direct sunlight.

Adding plenty of fish (salmon, tuna, sardines), oranges, spinach, mushrooms and eggs will help to boost your vitamin D to sufficient levels.

3. Take Vitamin D Supplements

Many common health problems are caused by a lack of vitamin D. The solution can be as simple as adding a specific vitamin D pill, gummy or multivitamin to your day.

There are many independent reviews online to help you find a good brand of vitamin. Be careful because some lists are filled with affiliate links that push you only to buy supplements. These lists are typically arranged by the highest-paid affiliate percentages versus the vitamin's effectiveness.

One supplement and vitamin company to consider is Thorne, which also has at-home vitamin D tests to measure your levels. The U.S. Olympic team allows athletes to use Thorne's supplements, because they contain zero banned substances.

4. Limit Your Overall Intake

You need to track how much vitamin D you are getting in a day. Your overall goal is to get 1,000-2,000IU, which is equivalent to 25-50 micrograms per day. The repercussions for not getting enough vitamin D or getting too much are serious. Too much vitamin D can cause increased calcium in blood vessels and even kidney stones.

According to the National Institutes of Health, "Excess amounts of vitamin D are toxic. Because vitamin D increases calcium absorption in the gastrointestinal tract, vitamin D toxicity results in nausea, vomiting, muscle weakness, neuropsychiatric disturbances, pain, loss of appetite, dehydration, polyuria, excessive thirst, and kidney stones."

Also from the NIH, "Obtaining sufficient vitamin D from natural (non fortified) food sources alone is difficult. For many people, consuming vitamin D-fortified foods and exposing themselves to sunlight are essential for maintaining a healthy vitamin D status. However, some groups might need dietary supplements to meet their vitamin D requirements. The following groups are among those most likely to have inadequate vitamin D status."

These groups are breastfed infants, older adults, those with limited sun exposure, people with darker skin and those with digestive issues and gastric bypasses.

If you have low energy levels, pain in your muscles and joints, sleep problems or even anxiety and mood swings, get your blood levels screened for vitamin D and other hormones to see if you have deficiencies that you can correct with better nutrition, more direct sunlight and smart supplementation. Follow the advice of a nutritionist to create a healthful and balanced diet alongside proper supplement recommendations.

Read more about Vitamin D from these references:

Stew Smith is a former Navy SEAL and fitness author certified as a Strength and Conditioning Specialist (CSCS) with the National Strength and Conditioning Association. Visit his Fitness eBook store if you're looking to start a workout program to create a healthy lifestyle. Send your fitness questions to

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