There's no doubt that vitamin D is essential. The nutrient is known to help build stronger bones, support the immune system, and more. Yet D deficiency is very common, affecting about 50 percent of the population worldwide. Some signs and symptoms of vitamin D deficiency include bone pain, muscle aches, and mood changes like depression. But low levels of vitamin D may also cause you to feel downright exhausted.
Estelle Darlyse Jean, MD, a board-certified cardiologist at MedStar Montgomery Medical Centre, explained that this is because vitamin D is involved in the cellular function of skeletal muscle. Research shows that low vitamin D levels can lead to muscle weakness and fatigue. "This fatigue can be the result of problems in the 'power stations' within each cell of the body called the mitochondria," Dr. Jean told POPSUGAR. Vitamin D supplementation may help resolve this issue, she explained, as prior studies have shown that increasing vitamin D levels in deficient patients can improve muscle efficiency, therefore lessening symptoms of fatigue.
Additionally, some research has linked vitamin D deficiency with lower sleep quality, sleep disturbances, and reduced sleep duration, explained Kristin Gillespie, MS, RD, CNSC, an advisor for Exercise With Style. It's likely then that healthy levels would help people sleep more soundly for longer periods of time, allowing them to feel more rested.
How Can I Increase My Vitamin D Intake?
Your body naturally produces vitamin D when it's exposed to sunlight. Gillespie recommends getting 10 to 30 minutes of midday sunlight several times a week for that reason — but you can also get vitamin D from foods including fatty fish like salmon and tuna, fish liver oils, cheese, and eggs.
Finally, if you're concerned you're not getting enough vitamin D from the sun and your diet, talk to your doctor about getting a simple blood test to find out if you're deficient. Depending on your levels, they may recommend that you start taking a vitamin D3 supplement.