Vitamin D for Athletes: Why Optimizing Levels Matters for Performance, Recovery, and Health
Caitlin Wells, PharmD, Sports Pharmacist
Vitamin D Is Basic — But Basic Still Matters
Most athletes are quick to ask about protein, creatine, electrolytes, caffeine, or whatever supplement is trending online. But sometimes the thing holding an athlete back is not the newest supplement. Sometimes it is a basic health marker that has never been checked.
Vitamin D is one of those markers.
It is not flashy. It is not something athletes are usually talking about in the weight room. However, low vitamin D can affect bone health, muscle function, recovery, immune health, and overall performance.
At OC Sports Performance, we do not guess with training. We measure sprint times. We track jumps. We record strength numbers. We look at whether the athlete is actually improving.
Health should be treated the same way. If an athlete is tired all the time, getting sick often, dealing with nagging pain, or not recovering well, vitamin D is one of the simple things worth looking at.
What Is Vitamin D?
Vitamin D is a fat-soluble vitamin that acts more like a hormone in the body.
Its biggest job is helping the body absorb calcium and phosphorus. Those minerals matter because athletes need strong bones, healthy muscle contraction, good nerve function, and the ability to handle the stress of training.
That is especially important for growing athletes. Their bodies are still developing, yet many of them are practicing, lifting, sprinting, playing games, traveling for tournaments, and trying to keep up with school at the same time.
That is a lot of stress on the system.
Vitamin D will not replace good training, enough food, quality sleep, or proper recovery. But if levels are low, it can absolutely be one of the things holding an athlete back.
How Do Athletes Get Vitamin D?
Athletes get vitamin D in three main ways: sunlight, food, and supplementation.
Sunlight is the most natural source. When UVB rays hit the skin, the body can make vitamin D. That sounds simple, but real life makes it harder.
In Bend and Central Oregon, athletes are in school most of the day. They train indoors. They wear sunscreen. They play indoor sports. They also spend a good part of the year in seasons where sun exposure is limited.
So while sunlight helps, it is not always enough.
Food can also help, but there are not a ton of foods that naturally contain high amounts of vitamin D. The best sources include salmon, trout, sardines, tuna, egg yolks, fortified milk, fortified orange juice, fortified cereals, and UV-exposed mushrooms.
For many athletes, supplementation becomes the most consistent way to improve levels, especially in the fall, winter, and spring.
But that does not mean athletes should blindly take huge doses. More is not always better. The better approach is simple: test, supplement if needed, and retest.
What Vitamin D Lab Should Athletes Get?
The lab to ask for is:
25-hydroxyvitamin D
It may also show up as:
25(OH)D
Vitamin D, 25-Hydroxy
25-Hydroxyvitamin D, serum
This is the lab that tells you vitamin D status. Parents and athletes should not just ask for “vitamin D” and assume the right test was ordered. The specific test you want is 25-hydroxyvitamin D.
This gives the best picture of stored vitamin D in the body and helps show whether an athlete is low, sufficient, or potentially too high.
Normal Vitamin D Levels vs. Optimal Levels
Most labs classify vitamin D levels like this:
Deficient: less than 20 ng/mL
Insufficient: 20–29 ng/mL
Generally sufficient: 30 ng/mL and above
Common athlete target range: roughly 40–60 ng/mL
Potential concern for excess: often above 100 ng/mL, especially if calcium is elevated
This is where athletes and parents need to understand the difference between “normal” and “optimal.”
A level of 31 ng/mL may be marked as normal on a lab report. But for an athlete training hard, competing often, and trying to stay healthy, many providers like to see that number closer to the 40–60 ng/mL range.
That does not mean every athlete needs to chase the exact same number. It means the number should be interpreted with context.
What sport do they play? Have they had stress fractures? Are they eating enough? Are they outside often? Are they tired? Are they getting sick? Are they recovering?
The lab matters. But the athlete in front of you matters too.
Why Vitamin D Matters for Athletic Performance
Vitamin D is not a magic pill. It is not going to take an athlete from average to elite by itself.
But low vitamin D can be one of the reasons an athlete is not adapting the way they should.
First, vitamin D supports bone health. That matters for athletes who sprint, jump, cut, lift, and compete year-round. If an athlete has shin pain, foot pain, back pain, bone stress injuries, or a history of stress fractures, vitamin D is worth checking.
Second, vitamin D plays a role in muscle function. Athletes need to produce force. They need to be explosive. They need their muscles to contract and recover. If vitamin D is low, the athlete may feel flat, weak, or like they are not bouncing back between training sessions.
Third, vitamin D supports immune health. This is a big one. Athletes who are constantly sick cannot train consistently. And without consistency, progress slows down.
Finally, vitamin D may help support recovery and overall health. Again, it does not replace sleep, food, hydration, or smart programming. But it is part of the foundation.
And the foundation matters.
How Often Should Athletes Test Vitamin D?
For most athletes, testing one to two times per year is a good starting point.
A simple plan would be to test once in late fall or winter, when levels are more likely to be low. Then, if supplementation is started or the dose is changed, retest in 8–12 weeks to see if the plan is actually working.
Some athletes may need more frequent testing. This is especially true if they have a history of stress fractures, low food intake, restrictive eating, repeated illness, chronic fatigue, or very limited sun exposure.
The point is not to test forever just to collect numbers. The point is to use the information to make better decisions.
How to Get More Vitamin D Through Food
Food alone may not fix low vitamin D, but it can help.
Better food sources include:
Salmon
Trout
Sardines
Tuna
Egg yolks
Fortified milk
Fortified orange juice
Fortified cereals
UV-exposed mushrooms
However, this needs to be part of a bigger nutrition plan. Vitamin D matters, but so do calories, protein, carbohydrates, calcium, magnesium, hydration, and sleep.
A lot of athletes want to perform better, but they are under-eating, under-sleeping, and trying to supplement their way out of a bad foundation.
That rarely works.
How to Supplement Vitamin D
For many athletes, a common maintenance dose is 1,000–2,000 IU of vitamin D3 daily, especially during the months when sun exposure is lower.
Some athletes may need more if their 25-hydroxyvitamin D level is low. But higher doses should be guided by a healthcare provider and followed with repeat labs.
Vitamin D3 is usually preferred because it tends to raise vitamin D levels well. Since vitamin D is fat-soluble, it is best taken with a meal that contains fat. That could be eggs, yogurt, avocado, olive oil, nuts, or a normal balanced meal.
Consider taking supplementing vitamin D with vitamin K.
Vitamin D helps the body absorb calcium. Vitamin K helps support proper calcium use in the body. Put simply, vitamin D helps get calcium in, and vitamin K helps direct calcium where we want it — like bones.
For athletes, that matters. Sprinting, jumping, cutting, lifting, and competing all stress the body. Strong bones are part of staying healthy and staying available.
A common combination is vitamin D3 with vitamin K2, often listed as MK-7 on the supplement label. Many products contain 1,000–2,000 IU of vitamin D3 with 90–120 mcg of vitamin K2.
Again, the goal is not to take every supplement on the shelf. The goal is to test, identify what the athlete actually needs, and then use the right dose consistently.
The Bottom Line for Athletes and Parents
Vitamin D is basic. But basic is usually where the biggest problems show up.
If an athlete wants to get stronger, faster, healthier, and more resilient, they need to cover the foundation first. That means training intelligently, eating enough food, getting enough protein, sleeping, hydrating, recovering, and making sure important health markers are not limiting progress.
At OC Sports Performance, we measure because it gives us the truth. Sprint times tell the truth. Jump numbers tell the truth. Strength numbers tell the truth.
Lab work can do the same thing.
If your athlete is serious about improving performance, staying healthy, and building a better foundation, book a free intro session here.
OC Sports Performance has helped thousands of athletes get stronger, run faster, and jump higher. Experience the difference!