Why You Need to Pay Attention to Vitamin D This Fall and Winter
By Caitlin Wells, PharmD – Sports Pharmacist
As the days get shorter and colder here in Bend, Oregon, your body’s natural Vitamin D levels start to drop. Less sunlight means less of this essential nutrient—and that can impact your strength, recovery, and immune system.
At OC, we know that training is only part of the equation. Nutrition, recovery, and key micronutrients like Vitamin D are what keep you performing well and feeling your best all year long.
What Vitamin D Does
This powerful nutrient acts more like a hormone than a vitamin. It influences nearly every system in your body—especially the ones that matter most to active adults and athletes.
- Muscle Strength and Performance: Helps muscles contract efficiently and supports recovery after training.
- Bone Health: Improves calcium absorption to keep bones dense and resilient.
- Immune Function: Strengthens your body’s defenses and helps reduce inflammation.
- Energy and Mood: Low levels are linked to fatigue and mood changes, especially during darker months.
When you’re training to feel, look, and perform better, maintaining healthy levels can make the difference between progress and burnout.
Why You’re Probably Not Getting Enough
Our main source of Vitamin D is sunlight—specifically UVB rays that trigger production in the skin. But in northern climates like Central Oregon, the sun’s angle from late fall through early spring is too low to make an adequate amount.
Even if you’re outside daily, bundled up for the cold or working long hours indoors, your body likely isn’t producing much during these months. That’s why deficiency is so common this time of year.
Supplementation Tips
When sunlight isn’t enough, supplementation can help you maintain optimal levels.
- Take with a meal: It’s a fat-soluble nutrient, so take it with healthy fats like avocado or olive oil for best absorption.
- Pair with Vitamin K2: K2 directs calcium into your bones instead of your arteries—important for both bone and heart health.
- Choose Vitamin D3 (cholecalciferol): D3 is more effective than D2 at maintaining healthy levels in the blood.
For most adults, daily supplementation during the colder months is a simple and effective way to support recovery and long-term health.
Why Some People Need More
Everyone metabolizes Vitamin D differently. Factors such as genetics, body composition, and gut health can affect how efficiently your body uses it.
If you train consistently but still struggle with fatigue, low motivation, or poor recovery, it might be time to check your levels.
The Right Lab Test
Ask your healthcare provider to order the 25-hydroxy Vitamin D test (25[OH]D)—this measures your stored amount and gives the most accurate picture of your status.
Avoid relying on the 1,25-dihydroxy test, which measures the active form and doesn’t reflect your true stores.
Bringing It All Together
This nutrient supports muscle strength, bone health, recovery, and immunity—all essential for training consistency and longevity.
Simple habits—like taking Vitamin D3 + K2 with a meal, getting your levels tested yearly, and staying consistent through the darker months—can help you stay strong and resilient year-round.
At OC Strength & Conditioning, we’re here to help you build a foundation of lifelong health—through every season. To see how we can help you stay strong, happy, and healthy, book your free intro session here.