Vitamin D and Sports Performance: What Athletes Should Know

How does vitamin D support athletes?

• Bone health Vitamin D helps the body absorb calcium and maintain the mineral balance needed for healthy bones. This is especially relevant in sports with high impact, high training loads or risk of bone stress injury. ^{[1, 2, 5, 7]}
• Muscle function Vitamin D receptors are present in skeletal muscle, and low vitamin D status has been associated with poorer muscle function. ^{[1, 2, 3, 7]}
• Recovery Vitamin D is biologically involved in muscle repair and inflammatory signalling, but clinical studies have not established a consistent recovery benefit from supplementation after exercise. ^{[1, 9]}
• Immune health and training consistency Vitamin D contributes to normal immune function. Maintaining adequate status is part of overall athlete health, although supplementation should not be viewed as a stand-alone way to prevent illness or guarantee uninterrupted training. ^{[1, 4, 5, 7]}

Can vitamin D improve sports performance?

Possibly in some athletes with low vitamin D status, but the evidence is mixed. Studies have reported associations between low vitamin D and poorer strength, power or musculoskeletal health. ^{[1, 3, 7, 12]}

Which athletes are more likely to have low vitamin D?

Athletes can have low vitamin D even in sunny countries. Risk depends on more than whether a sport is played indoors or outdoors. A 2023 systematic review found that indoor athletes tended to have somewhat lower vitamin D levels after accounting for factors such as season and ethnicity. ^{[1, 8]}

Athletes who may deserve closer assessment include those who: ^{[1, 7]}

• train mostly indoors, at night, or at times with little UVB exposure;
• have darker skin pigmentation;
• wear clothing that covers most of the skin or deliberately avoid sun exposure;
• have conditions that reduce absorption of fat-soluble vitamins, such as some gastrointestinal disorders;
• have a history of vitamin D deficiency, bone stress injury or recurrent musculoskeletal problems.

Do indoor athletes automatically need vitamin D supplements?

Not necessarily. Indoor training can be one risk factor, but other factors such as the season, sun exposure, skin pigmentation, diet, health conditions and previous blood results all matter. A pharmacist, doctor or sports dietitian can help assess the overall picture. ^{[1, 7, 8]}

What are the best food sources of vitamin D for athletes?

Only a limited number of foods naturally contain substantial vitamin D, so athletes with low sun exposure may need to make deliberate food choices. ^{[1, 5, 6]}

Sun exposure can also contribute to vitamin D production, but there is no single “right” number of minutes for everyone. UV intensity, time of day, skin pigmentation, clothing and other factors change vitamin D synthesis, and deliberate overexposure is not recommended because of sunburn and skin-cancer risk. ^{[1, 2, 7]}

Should athletes get a vitamin D level test?

The main blood marker used to assess vitamin D status is serum 25-hydroxyvitamin D [25(OH)D]. Studies have shown that vitamin D insufficiency can be common among athletes, even in those who train outdoors or live in sunny environments. Therefore, athletes should not assume that regular sun exposure alone guarantees adequate vitamin D status. Checking vitamin D levels can help athletes understand their individual status and identify insufficiency or deficiency that might otherwise go unnoticed. ^{[1, 5, 7, 10, 13, 14, 15]}

Should athletes take vitamin D supplements?

Supplementation can be appropriate when an athlete has low vitamin D or another clear indication, but the dose and duration should be individualised. More is not necessarily better: excessive vitamin D intake can cause harmful calcium elevations and other complications. Athletes should avoid self-prescribing high-dose regimens and discuss supplementation with a pharmacist, doctor or sports dietitian. ^{[1, 5, 7, 10]}

The bottom line for athletes

Vitamin D is important for healthy bones, muscles and normal body function, but it should not be marketed as a shortcut to better performance. Athletes are most likely to benefit from a sensible food-first diet, appropriate sun-safety habits and professional assessment when low vitamin D is suspected. If supplementation is needed, the goal is to correct an identified need safely rather than to take the highest possible dose. ^{[1, 5, 7, 10, 12]}

Frequently asked questions about vitamin D and sports performance

Related Health Info

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• Vitamin D Deficiency: Causes, Symptoms and Solutions →