There’s a reason Vitamin D is often referred to as the “Sunshine Vitamin.” Our bodies create Vitamin D when our skin is exposed to the sun. It’s important for a triathlete, who spends a great deal of time training and competing outdoors, to understand that not all sunlight is created equal when it comes to helping the body produce Vitamin D.

One of the most important factors to consider when trying to determine if your body is effectively making Vitamin D from sunlight is time of day. The middle of the day is the best time to make Vitamin D. An easy-to-follow guideline is that if your shadow is longer than you are tall you really aren’t making much Vitamin D.

This is not to say that we shouldn’t protect ourselves from the sun’s more harmful rays. Sunscreen is essential for outdoor athletes, especially during non-peak Vitamin D hours. However, it’s important to remember that, while sunscreen is beneficial for protecting our skin, it unfortunately also blocks the body’s ability to make Vitamin D as efficiently as possible.

Not only is Vitamin D associated with increasing beneficial performance measures, it is also associated with decreasing the risk of injury, making maintaining adequate levels of Vitamin D vital for athletes of all levels. Research has also found potential benefits for athletes in terms of oxygen utilization, force production and decreasing inflammation.

So how does someone determine if they’re experiencing Vitamin D deficiency? Some people may have no symptoms at all, while others may experience tiredness and general aches and pains. Severe Vitamin D deficiency may cause pain in your bones and weakness, which may mean you have difficulty getting around, let alone training and competing. If you think you may have Vitamin D deficiency, you should see your physician, or have a blood test to check your Vitamin D levels.

Staying on top of your Vitamin D is important and, while you can get some from food sources such as fish, dairy and fortified cereal, typically we don’t get enough from food to meet our daily needs. If you are unable to get adequate midday sun it may be necessary to rely on Vitamin D supplementation to achieve daily recommended intakes and maintain healthy serum levels.

Vitamin D plays so many vital roles in our health, performance and recovery. With some simple planning and using proper precautions, an outdoor athlete can raise their game by letting the sun work for them.