My Muscles Ached and My Mood Suffered. Low Vitamin D Was the Culprit.
Fatigue, aching muscles, and slow recovery aren’t always signs of training too hard. What you need to know about vitamin D deficiency and its effects on runners.
Who doesn’t want more of the sunshine vitamin? The importance of vitamin D has been extensively written about over the years – it helps keep nearly every major muscle, bone, and nerve healthy. Low vitamin D is more common than you think, and without it, your recovery is compromised – your muscles ache and your mood suffers.
Just because you spend plenty of time soaking up the sun’s rays doesn’t mean you’re getting enough…
But spoiler alert: Just because you spend plenty of time soaking up the sun’s rays doesn’t mean you’re getting enough vitamin D to meet your needs. I learned that the hard way a few years ago, and it’s a lesson all runners can benefit from as they study up on maintaining healthy training.
Abnormal Fatigue and Sore Muscles: I headed into a track season feeling abnormally fatigued and sore. It was an “I don’t even want to run two kilometres,” kind of fatigue. I thought going to bed earlier and prioritising recovery could help me bounce back. But that low energy stuck out on the track like a sore thumb. I ran slower than I had in high school, and I couldn’t figure out why.
I still remember the breaking point as if it happened yesterday. When I could barely manage half of a 20 x 300-metre workout, I knew I couldn’t continue running in such a depleted state. I told my coach I felt like I was running through water, unable to maintain an up-tempo pace without completely dying.
So my coach suggested I head to the health centre for some blood work. I had a history of low iron levels (and I recommend all runners learn more about the effects of iron on health and performance), so we both thought a blood test might provide some answers. But when the doctor followed up with my test results, my iron levels were higher than when I had been tested a year prior. The real culprit turned out to be a nutrient I never really thought much about before: vitamin D.
Endurance Runners Use Up Their Stores of Nutrients More Quickly: The doctor explained I had enough of a deficiency to see a noticeable impact on my energy levels and running performance. And, as confirmed by the physician, my symptoms aligned perfectly with vitamin D deficiency. I identified fatigue, muscle aches, and even noticeable mood swings as possible signs that I lacked adequate vitamin D.
Looking back on it now, many factors added up to make for the perfect storm. Not only does research show that endurance runners more commonly experience vitamin D deficiency because they use up their stores of the nutrient more quickly than non-runners, but additional studies explain that female runners experience deficiencies in vitamin D, iron, and calcium more frequently than their male counterparts.
Just because I ran outside every day and walked around my college campus didn’t mean I got enough of the sunshine vitamin naturally to support my body. “Because of the ongoing stress from running and training, there’s a lot of turnover of bone absorption and reconstruction, as well as muscle breakdown and reconstruction, so there’s a higher metabolic turnover and need to maintain adequate vitamin D levels,” Alex McDonald, M.D., a family medicine physician specialising in sports medicine, told Runner’s World.
How Do You Replenish Vitamin D? Thankfully, you can address vitamin D deficiency with some simple steps. The doctor suggested I take 2,000 IU of a vitamin D supplement once a day to adequately supply my body and eventually get rid of my fatigue, muscle aches, and mood swings. Make sure you consult your healthcare provider before taking any supplements.
She also told me to prioritise rich sources of vitamin D in my diet – fortified breakfast cereals and dairy, among other products; however, there are surprisingly very few foods that provide much of the nutrient. Experts we spoke to for our all-things vitamin D guide also recommended those methods for boosting vitamin D levels, noting that while it’s best to get nutrients through whole foods, vitamin D may be the exception because it’s not found in a wide variety of foods.
I didn’t immediately see night-and-day improvements. But after a few weeks of supplementation and less aggressive training to let my body recover, I finally felt more energised during all parts of my day. Once I entered my summer training phase, I ran faster, lifted more, and felt healthier than I had previously.
It’s important to stay in-the-know of the impacts nutrients like vitamin D can have on your body as a runner. If you notice your body feels more sluggish than normal for a prolonged period of time, or if you see drastic changes in your energy and running performance, don’t wait until you feel like you’re running in slow motion like I did. We have plenty of expert content on our website to keep you updated on all things nutrition and health; we have content dedicated to health and injuries, and it’s full of expert insights on how to become a stronger, healthier runner.
